New performance major questions

This forum is for the Fordson New Major, including the Super Major and the Power Major.
EdWaters
Not Quite Blue Yet
Posts: 7
Joined: Sun Jul 17, 2022 1:36 pm

New performance major questions

Post by EdWaters »

I have a 1964 new performance major I’m restoring and have a couple of questions please. The gearbox drives and sounds lovely apart from top gear 6th at low idle it has an awful chatter rattle grinding noise which goes away once your rev it up more. After doing some research I’m led to believe it could be the rear bearing? Is there any way of investigating further or what to look out for before I take it all apart? Or anyone else had this problem?
Secondly, I have the lower geared 8 tooth pinion would any major pinion and crown wheel fit or what do I need to change ratios? is it quite straightforward job to change over to 10 teeth. Many thanks Ed

mathias1
Site Governance Team
Site Governance Team
Posts: 787
Joined: Fri Jul 08, 2016 7:11 pm
Location: Antwerp - Belgium

Re: New performance major questions

Post by mathias1 »

Hello Ed,

Welcome to the board.

The bearing at the top is known to fail when there's not enough oil in gearbox. So first thing you can check is the oil level in the gearbox. It should be almost at te level of the filler plug. The oil level in the back is at a much lower level. If one of the 2 seals between gearbox and rear end is failing, the oil in the gearbox will flow to the rear end. I currently have this problem on one of my tractors.
If you have a small camera you can look into the filler cap and see the bearing from there. Or you can take of the side plate on the left.
Here you have a look inside one of my tractors (also a new performance) which also had a low oil level.
Image
You can clearly see the missing bits in the bearing.

As for the pinion and crown wheel, you need to replace them as a set. As far as I know any non -new performance pinion and crown wheel will fit.
I never have changed the crown wheel myself.
Just in case you have 4wd tractor (roadless or selene) there will become a mismatch between front and rear axle.. For the county conversion, I don't see a problem there.
Just behind the gear stick you will also find a number which will refer to what speed you have.
Fordson Super Major New Performance
County Super 4 built on the Fordson Super Major
Selene built on the Fordson Super Major New Performance with Silvant winch

Billy26F5
True Blue
Posts: 1912
Joined: Fri Jun 26, 2020 12:01 am
Location: On Billy

Re: New performance major questions

Post by Billy26F5 »

Mathias has already covered it in detail, but there are a couple of points to add.
You can't use a crown wheel and pinion from a Major or Power Major as although they have the same ratio, the diff is different (no diff lock), so they won't fit. Preferably you should find a set from the same period as your tractor, but any Super Major will do.
As for the gearbox noise, see if the gerbox oil level is the same as the rear axle or not, this will tell you which seal has gone, if all levels are fine then check the bearing through the filler plug. The whole gearbox will have to come out to replace that bearing.
Sandy
ImageImageImage

mathias1
Site Governance Team
Site Governance Team
Posts: 787
Joined: Fri Jul 08, 2016 7:11 pm
Location: Antwerp - Belgium

Re: New performance major questions

Post by mathias1 »

Correction, need indeed super major parts for the diff. In the parts manual they make the difference
Fordson Super Major New Performance
County Super 4 built on the Fordson Super Major
Selene built on the Fordson Super Major New Performance with Silvant winch

shepp
True Blue
Posts: 448
Joined: Thu Oct 06, 2011 8:24 pm
Location: Lancashire

Re: New performance major questions

Post by shepp »

First things first, if the gearbox oil level is down due to the gearbox output shaft seal and/or the double lipped oil seal in the PTO gearbox having failed (common issue after many years of work and deterioration) letting oil flow from the gearbox into the back axle then you will get that rattle anyway even if the back bearing is intact. So check the gearbox oil level, check the bearing if you can see it and if it looks OK top up with oil and see how the rattle is then. If the seals have failed then you will need to split the tractor between the gearbox and back end and do the gearbox output shaft seal, and then withdraw the PTO shaft, drop the PTO gearbox and replace the double lipped seal in the PTO gearbox.

Turning to rear axle ratios, this is a New Performance tractor so why would you want to bastardise it by changing the crown wheel and pinion ratios? Especially if as you say you are restoring it , losing it's original build spec. will affect it's value. Yes, just a very few late NP tractors were available specially ordered with the original blue/orange Super Major final drive ratios for special situations, but changing the final drive ratios will not make this tractor one of those special orders! Also be aware that the NP tractor actual gearbox ratios were different to the blue/orange models, every gear ratio except 5th was different so as to give slower and a better spread of speeds for PTO work, it was not just the final drive ratios that were different. Changing the final drive ratio to blue/orange spec will only give a small increase in top speed because the NP 6th gear ratio is different to the blue/orange model 6th gear ratio!

If you do decide to do it then you will need a matched pinion and crown wheel from a blue/orange Super Major. If you decide to swap a complete blue/orange diff assembly and associated pinion into the tractor make sure that you either use the original bull pinion shafts and bull gears OR you swap the matched bull pinion shafts and bull gears from the blue orange model as well. This is because there is a very very marginal difference in the diameter of the bull gears in NP tractors to those in blue/orange tractors, if bull pinion shafts and bull gears are mismatched there will be a failure.

Personally leave the final drive alone, there is little to be gained in 6th gear top speed for a lot of messing and work involved - for example do you understand and would you be capable of setting up the pinion to crown wheel backlash after changing the crown wheel and pinion?
Last edited by shepp on Wed Aug 10, 2022 9:00 am, edited 1 time in total.
1946 E27N, 1952 Major Diesel, 1959 Power Major, 1962 Dexta, 1962 Super Dexta, 1963 Super Dexta NP, 1964 Super Major NP, 1965 Super Dexta 3000, 1966 Major 4000, 1967 3000 PF, 1994 5640,plus Basildon built NH.

Billy26F5
True Blue
Posts: 1912
Joined: Fri Jun 26, 2020 12:01 am
Location: On Billy

Re: New performance major questions

Post by Billy26F5 »

If the PTO seal has leaked the oil is at the same level in the gearbox and rear axle. If it's the main seal the oil wil be just below it in the gearbox, with the rear axle level being way below, though still higher than it should be. If the rear axle level is a bit high fill the outer axle bearings with plenty of grease to keep the oil from leaking out easily.
Sandy
ImageImageImage

EdWaters
Not Quite Blue Yet
Posts: 7
Joined: Sun Jul 17, 2022 1:36 pm

Re: New performance major questions

Post by EdWaters »

Hi, thanks very much for all of your really helpful replies. It was really low with oil in the gearbox when I purchased it so will have to split it and do the seals. After topping up with oil and test driving thoroughly again the noise did not make any difference. I’ve since taken the side cover off that houses the gear linkage to inspect the rear top bearing. It’s not missing any rollers but there seems to be a lot of forward and back movement and a little bit up and down. I’m thinking once dismantled it must be a lot more noticeable that bearing is worn? Everything else inside seems in good condition all the gears look fine.
With the diff ratios, I think your right shepp I’m going to leave well alone, with all the extra work there is very little to gain and originality lost.

Emiel
True Blue
Posts: 729
Joined: Wed Apr 16, 2008 3:22 pm
Location: Netherlands

Re: New performance major questions

Post by Emiel »

Yes. Good decision to keep it original and good luck with the repair.
Best regards

Emiel

N 1937, E27N 1948, 8N 1949, E27N 1950, E1A Diesel 1953, E1ADKN PP 1956, Dexta 1959, NH Clayson M103 1964

Emiel
True Blue
Posts: 729
Joined: Wed Apr 16, 2008 3:22 pm
Location: Netherlands

Re: New performance major questions

Post by Emiel »

Yes. Good decision to keep it original and good luck with the repair.
Best regards

Emiel

N 1937, E27N 1948, 8N 1949, E27N 1950, E1A Diesel 1953, E1ADKN PP 1956, Dexta 1959, NH Clayson M103 1964

Roadless63
True Blue
Posts: 261
Joined: Tue May 06, 2008 10:49 pm
Location: Derby/Hants

Re: New performance major questions

Post by Roadless63 »

I think the 3.5 diff was more common than you think, yes a early np all seem to be the low diff but by late 63 the tables seem to have turned in favour of the 3.5.
Regards, Ed
shepp wrote:
Tue Aug 09, 2022 10:41 pm
First things first, if the gearbox oil level is down due to the gearbox output shaft seal and/or the double lipped oil seal in the PTO gearbox having failed (common issue after many years of work and deterioration) letting oil flow from the gearbox into the back axle then you will get that rattle anyway even if the back bearing is intact. So check the gearbox oil level, check the bearing if you can see it and if it looks OK top up with oil and see how the rattle is then. If the seals have failed then you will need to split the tractor between the gearbox and back end and do the gearbox output shaft seal, and then withdraw the PTO shaft, drop the PTO gearbox and replace the double lipped seal in the PTO gearbox.

Turning to rear axle ratios, this is a New Performance tractor so why would you want to bastardise it by changing the crown wheel and pinion ratios? Especially if as you say you are restoring it , losing it's original build spec. will affect it's value. Yes, just a very few late NP tractors were available specially ordered with the original blue/orange Super Major final drive ratios for special situations, but changing the final drive ratios will not make this tractor one of those special orders! Also be aware that the NP tractor actual gearbox ratios were different to the blue/orange models, every gear ratio except 5th was different so as to give slower and a better spread of speeds for PTO work, it was not just the final drive ratios that were different. Changing the final drive ratio to blue/orange spec will only give a small increase in top speed because the NP 6th gear ratio is different to the blue/orange model 6th gear ratio!

If you do decide to do it then you will need a matched pinion and crown wheel from a blue/orange Super Major. If you decide to swap a complete blue/orange diff assembly and associated pinion into the tractor make sure that you either use the original bull pinion shafts and bull gears OR you swap the matched bull pinion shafts and bull gears from the blue orange model as well. This is because there is a very very marginal difference in the diameter of the bull gears in NP tractors to those in blue/orange tractors, if bull pinion shafts and bull gears are mismatched there will be a failure.

Personally leave the final drive alone, there is little to be gained in 6th gear top speed for a lot of messing and work involved - for example do you understand and would you be capable of setting up the pinion to crown wheel backlash after changing the crown wheel and pinion?

Billy26F5
True Blue
Posts: 1912
Joined: Fri Jun 26, 2020 12:01 am
Location: On Billy

Re: New performance major questions

Post by Billy26F5 »

I hadn't thought of that, I think people were prioritising ploughing, baling and road speed. I think Ebro never offered the 3.5 when they moved on to the 4.375, just after Ford stopped Major production I think. I'll confirm if that's not the case when Super Billy is running.
The bearing should have no play, so you'll see fairly quickly if it's in trouble.
Sandy
ImageImageImage

shepp
True Blue
Posts: 448
Joined: Thu Oct 06, 2011 8:24 pm
Location: Lancashire

Re: New performance major questions

Post by shepp »

With the NP tractor Ford upped the engine revs at which 540 rpm PTO speed was achieved from 1200rpm to very nearly 1500rpm, a ratio of 5:4 increase, giving a significant 30% + increase in PTO power at standard PTO speed. Horsepower at the PTO shaft was always an issue with Major tractor variants as more power demanding implements such as forage harvesters, rotary muckspreaders and drum mowers came into use. Failures of the PTO gearbox casing became more of an issue due to high torque and shear stresses in the slow running PTO system. The only option was a raised PTO unit giving 540 rpm at the PTO with an engine speed of 1600rpm - but this came with the drawback of increased and too fast forward speeds which necessitated a reduction gearbox such as the Howard to give useable forward speeds.
With the original blue orange final drive ratio of 3.5:1 and original blue/orange gearbox ratios this increase in engine speed with the NP tractor would have made the forward speeds at 540 rpm PTO speed faster by a ratio of 5:4. The first task was to adjust for that forward speed increase and this was done with the 4.375:1 final drive ratio - 4.375:3.5 equates to a ratio of 5:4. So without any change of gearbox ratios forward speeds of the NP tractor with the 4.375:1 final drive and the blue orange tractor with the 3.5:1 final drive would have been the same at 540 rpm PTO speed.
However the spread of speeds for PTO work was always less than ideal with the blue/orange Super Major, Power Major and Major, and in this respect, and also out and out PTO power, the DB 990 was really showing Ford the way home and was very superior for PTO work. Having got a significant increase in PTO horsepower at 540 rpm with the NP PTO gearing Ford needed to sort out the spread of forward speeds and so every main gearbox ratio except 5th gear was changed to give a better spread of speeds for PTO work, and in fact they seem to have followed the DB 990 pattern quite closely.

So forward speeds were generally slower with the revised NP gearbox ratios and at reduced engine revs even slower again. This did not suit all users such as those on light draft work and so eventually the original 3.5:1 final drive ratio was made available as a special order. However you could not order the original blue/orange gearbox ratios, only the revised and slower NP gearbox and it' s ratios were available, and so there was very little to be gained by the customers who had been moaning about slow speeds with the NP tractor. If you look in the operators handbook all speeds are shown for the blue/orange tractor with the 3.5:1 ratio, the NP tractor with the 4.375:1 ratio and the NP tractor with the 3.5:1 ratio.

It would be interesting if numbers were available for NP tractors ordered with the 3.5:1 final drive, with a production run of only May 1963 to July 1964 there would have been barely enough time for users to determine what ratios they wanted - I would think that very few NP tractors were actually traded in against another NP tractor, most would have been traded against a new 6X model.
1946 E27N, 1952 Major Diesel, 1959 Power Major, 1962 Dexta, 1962 Super Dexta, 1963 Super Dexta NP, 1964 Super Major NP, 1965 Super Dexta 3000, 1966 Major 4000, 1967 3000 PF, 1994 5640,plus Basildon built NH.

Billy26F5
True Blue
Posts: 1912
Joined: Fri Jun 26, 2020 12:01 am
Location: On Billy

Re: New performance major questions

Post by Billy26F5 »

Very interesting Shepp, I think 6th was actually made faster by swapping the number of teeth (while the other gears were slowed down a different way), but with the slower crown wheel and pinion this meant a considerable reduction in speed for road work, this is where I would have expected most complaints to have come from first, perhaps followed by farmers who didn't really have much PTO stuff yet and thought ploughing had got slower (although I think you can compensate for that by working a gear higher on a 4.375 than on a 3.5, again need to check this with Super Billy). I also seem to remember reading about complaints from loosing the ideal baling speed, but I might be wrong on that. I would have expected they would have swapped the crown wheels and pinions rather than replaced a basically new tractor, I would be pretty sure most 3.5 ratio NP Super Major's spent quite a long time on the road, for there a drop in speed would be very noticeable.
Sandy
ImageImageImage

Roadless63
True Blue
Posts: 261
Joined: Tue May 06, 2008 10:49 pm
Location: Derby/Hants

Re: New performance major questions

Post by Roadless63 »

We operate a number of majors on hay and now not so much with straw. The NP with 3.5 diff is generally in 4th gear for most of the work we do, baling 3rd and 4th with correctly sized swathes. The low diff NP is not suited to this work, too low geared. I suspect the lower gearing was aimed at higher loading draft and pto work such as silage choppers but we don't do any silage. Drum mowers will run much faster, probably 5th gear if the ground was smooth enough.
The blue orange with raised pto is a bit quicker in all but top gear. Again for the work we do it hasn't been a problem.
On the road running solo the NP with 3.5 diff is a quick machine and gets between jobs easily. You do notice on the steeper climbs the blue orange holds onto top better being that bit lower geared. The low diff np is noticeably slower for road work, I think this was what customers picked up most on.
We currently have 15 np supers here, the only low diff ones are from May to October 63 I think, then they quickly transition to the 3.5 diff right up to a couple made in September 64. We have 2 np roadless super majors, both are 63 machines. The June 63 is slow diff, the September 63 is a fast one.

Billy26F5
True Blue
Posts: 1912
Joined: Fri Jun 26, 2020 12:01 am
Location: On Billy

Re: New performance major questions

Post by Billy26F5 »

That's great to be able to compare all these things, it seems I did remember the thing about baling! Great to have one of each for the two Roadless ones too. I think I'm right in thinking you got a prototype Super Major a while ago, how does that one compare with the production ones? We don't have any raised PTO, but I don't think we really need one at the moment.
Sandy
ImageImageImage

Roadless63
True Blue
Posts: 261
Joined: Tue May 06, 2008 10:49 pm
Location: Derby/Hants

Re: New performance major questions

Post by Roadless63 »

The prototype super major is the same as a blue orange super in terms of ratios (and also power/diesel major come to that). It has the diff lock, disc brakes and hydraulic top cover per a super major. Engine wise it has a minimec pump fitted so was most likely used to test out the mechanical injection pump ahead of it being used in production in mid 1962.

Billy26F5
True Blue
Posts: 1912
Joined: Fri Jun 26, 2020 12:01 am
Location: On Billy

Re: New performance major questions

Post by Billy26F5 »

I thought that the main things would be the same as production Super Major's, but I thought the prototype parts would show up the hand made patterns, being notably different to any production part in certain details, I was also wondering if it might have the minimec fitted in a different way because of having the earlier block, unless it has had a later one fitted for the minimec. I would have thought the minimec would have been tested before 1613500, when the new block appeared (mid 61). Sorry about getting this thread mixed up but I do feel that having such a special Major next to more normal ones makes this even more interesting.
Sandy
ImageImageImage

shepp
True Blue
Posts: 448
Joined: Thu Oct 06, 2011 8:24 pm
Location: Lancashire

Re: New performance major questions

Post by shepp »

Interesting point about the pump mounting given the block change mid 1961, it would be good to know if the engine has a serial number. The "Commercial Motor" magazine reported in February 1962 that the Thames Trader 4 cylinder engine was now fitted with the minimec pump which had been fitted to the 6 cylinder engine sometime in 1961 - think I have got that the right way round, I'll have to check my research! The first Super Major with the minimec was later on in April 1962.

I had always thought that the original prototype was the experimental Power Major fitted with draft control hydraulics and pictured in Stuart Gibbard' s book.

Update! No, it was the other way round, the minimec was fitted to the 4 cylinder engine used in the truck in February 1962, and was fitted to the 6 cylinder truck engine from June 1962 onwards.
Last edited by shepp on Thu Sep 01, 2022 12:17 pm, edited 1 time in total.
1946 E27N, 1952 Major Diesel, 1959 Power Major, 1962 Dexta, 1962 Super Dexta, 1963 Super Dexta NP, 1964 Super Major NP, 1965 Super Dexta 3000, 1966 Major 4000, 1967 3000 PF, 1994 5640,plus Basildon built NH.

shepp
True Blue
Posts: 448
Joined: Thu Oct 06, 2011 8:24 pm
Location: Lancashire

Re: New performance major questions

Post by shepp »

Another interesting point Roadless63 is you say that you have 2 NP Roadless tractors, the June 63 being a low speed 4.375:1 diff, the September 63 being a high speed 3.5:1 diff. There would have to be different gearing in the 4wd system to accommodate these differences, either in the sandwich box or in the front diff itself, which is the case??
1946 E27N, 1952 Major Diesel, 1959 Power Major, 1962 Dexta, 1962 Super Dexta, 1963 Super Dexta NP, 1964 Super Major NP, 1965 Super Dexta 3000, 1966 Major 4000, 1967 3000 PF, 1994 5640,plus Basildon built NH.

mathias1
Site Governance Team
Site Governance Team
Posts: 787
Joined: Fri Jul 08, 2016 7:11 pm
Location: Antwerp - Belgium

Re: New performance major questions

Post by mathias1 »

Selene sept 63 here is a slow one. It does have the numbered stamped behind the gearstick.
Fordson Super Major New Performance
County Super 4 built on the Fordson Super Major
Selene built on the Fordson Super Major New Performance with Silvant winch

Billy26F5
True Blue
Posts: 1912
Joined: Fri Jun 26, 2020 12:01 am
Location: On Billy

Re: New performance major questions

Post by Billy26F5 »

I had always had the impression the minimec appeared on 4 and 6 cyl lorry, industrial and tractor in April 62, I think many industrial engines were fitted with the earlier mechanical governors well before then, which might help to confuse the issue. I definitely know that the minimec coincides with the Mk2 Thames Trader, for it was one of the main selling points (the Super Dexta did the same for the Dexta).
I would expect they used different ratios in the transfer box, as it's much simpler than different crown wheel and pinion sets, but I don't know.
Sandy
ImageImageImage

shepp
True Blue
Posts: 448
Joined: Thu Oct 06, 2011 8:24 pm
Location: Lancashire

Re: New performance major questions

Post by shepp »

The minimec was fitted to the 4 cylinder 592E engine in the Trader Normal Control bonneted truck which was launched in February 1962, and at the same time it was fitted to the 4 cylinder engine in the lighter version of the existing Mark 1 Forward Control Trader .The Mark 2 Forward Control Trader was introduced to the trade in mid May 1962 and to the public on 1 June 1962, and it was announced then that the 6 cylinder 590E engine was now fitted with the minimec as well as the 4 cylinder 592E engine.
As far as the tractors go, it was announced in April 1962 coinciding with the production launch of the new minimec governed Super Dexta that the Dexta and Super Major tractors would now also be fitted with the minimec pump, I have a copy of Farm Mechanisation somewhere that contains the article.
The minimec pump was so named because apart from other improvements over the SP pumps it used a very compact mechanical governor, hence "mini". Industrial engines of both 4 and 6 cylinders were available with mechanical governors long before the minimec was developed, these governors were quite bulky items. The Mark1 and Mark2 industrial engines could be fitted with the GV mechanical governor pump, the Mark3 engine could be fitted with the GM mechanical governor pump. Different governed speed ranges were available for both pumps depending on the usage. Many Clayson combines for example were fitted with engines with GV and GM pumps. After the introduction of the minimec pump the fitting of the GM type pump progressively declined.
1946 E27N, 1952 Major Diesel, 1959 Power Major, 1962 Dexta, 1962 Super Dexta, 1963 Super Dexta NP, 1964 Super Major NP, 1965 Super Dexta 3000, 1966 Major 4000, 1967 3000 PF, 1994 5640,plus Basildon built NH.

Roadless63
True Blue
Posts: 261
Joined: Tue May 06, 2008 10:49 pm
Location: Derby/Hants

Re: New performance major questions

Post by Roadless63 »

The casting date on the block is August 1960 I believe. It doesn't have the casting detail for the small glass sediment bowl located close to the join with the sump but instead a neat folded bracket to position the bowl in the correct place. I've not really studied the injector pump mounting detail, I probably ought to compare it with a production tractor.
I've never worked out how to post pictures on here otherwise I'd upload some.

Billy26F5 wrote:
Tue Aug 30, 2022 9:39 pm
I thought that the main things would be the same as production Super Major's, but I thought the prototype parts would show up the hand made patterns, being notably different to any production part in certain details, I was also wondering if it might have the minimec fitted in a different way because of having the earlier block, unless it has had a later one fitted for the minimec. I would have thought the minimec would have been tested before 1613500, when the new block appeared (mid 61). Sorry about getting this thread mixed up but I do feel that having such a special Major next to more normal ones makes this even more interesting.
Sandy

Roadless63
True Blue
Posts: 261
Joined: Tue May 06, 2008 10:49 pm
Location: Derby/Hants

Re: New performance major questions

Post by Roadless63 »

According to Stuart there were 25 prototypes. The one I have 599phk was registered to the Ford motor company in May 1959. The back end casting is dated late 58 or early 59 I can't quite remember off hand. It has disc brakes fitted. The top cover is super major but devoid of any casting marks. Similarly the front cross member is devoid of casting date. Other features are "Rainham" painted on the engine block and cylinder head, a large X On the gearbox and PV12 painted on the nose cone.

shepp wrote:
Wed Aug 31, 2022 9:31 pm
Interesting point about the pump mounting given the block change mid 1961, it would be good to know if the engine has a serial number. The "Commercial Motor" magazine reported in February 1962 that the Thames Trader 4 cylinder engine was now fitted with the minimec pump which had been fitted to the 6 cylinder engine sometime in 1961 - think I have got that the right way round, I'll have to check my research! The first Super Major with the minimec was later on in April 1962.

I had always thought that the original prototype was the experimental Power Major fitted with draft control hydraulics and pictured in Stuart Gibbard' s book.

Update! No, it was the other way round, the minimec was fitted to the 4 cylinder engine used in the truck in February 1962, and was fitted to the 6 cylinder truck engine from June 1962 onwards.

Roadless63
True Blue
Posts: 261
Joined: Tue May 06, 2008 10:49 pm
Location: Derby/Hants

Re: New performance major questions

Post by Roadless63 »

The gearing is done in the transfer box. The casing is machined to suit different gear sets. The same was done for the 6/4 ploughmaster which had 38" rear wheels and again two possible diff ratios. The np roadless conversions had the mk2 transfer box with lower output shaft to make prop angle better.
shepp wrote:
Wed Aug 31, 2022 9:53 pm
Another interesting point Roadless63 is you say that you have 2 NP Roadless tractors, the June 63 being a low speed 4.375:1 diff, the September 63 being a high speed 3.5:1 diff. There would have to be different gearing in the 4wd system to accommodate these differences, either in the sandwich box or in the front diff itself, which is the case??

Post Reply