Select O Speed transmissions

[Kiwi Kev]

Although I don't have a SOS tractor, I'm very interested in their engineering.
Does anybody have any good info or links to good websites on SOS transmissions.
I know they weren't very popular with drivers, why was that!
Thanks
Kiwi Kev

[brockwood]

Hi kev While iv read some good articles I don’t have them to hand so I can only offer user knowledge we operated a 3000 from 65 til 85 til the motor blew it was then broken for parts. Uncles had a 3000 and a 4000 we now have recetenly got a 69 model as part of our collection. I believe the 3000 were the worst most did not last long back in the day you could not give them away thou I think they fixed most faults in the later ones but the rep was gone .apparently they were rushed in to production and weren’t properly tested unlike Moden power shifts they aren’t computer controlled so that some shifts are quite jerky this is because some shifts are more complex 4 to 5 8 to 9 and use more oil flow with the result that it nearly stops moving and then jerks this is why they were know as jerkamatits also depends how tight the bands are another prob is they tried to do to much with the gears while there is 10 the first 4 are creep 5 to 8 field 9 /10 road where a modern box would have separate hi low or more ranges on top of power shift so for most paddock work there is only 4 or 5 gears, to protect the trans they have a fixed overload clutch where a normal clutch would be ours like most tore the centre out of the plate so out came a heavier one then after time they strip the splines as the input shaft spine to the box is short .like any autotrans they do orings and need servicing which was proby a change after manuals which you never thought about. they work in reverse senses to most things in that the some of the bands are applied by springs and are held off by oil so if there is a pressure problem you get in 2 gears at once which is why some got very hot .in park its deliberate so when stoped or stalled the pressure drops and it just stops so you want to be still when pulling the stopper as I know from experience having nearly gone over the bonnet .to tow home a dud theirs a dog clutch on the diff to let it roll hope thats of some help b

[Kiwi Kev]

Brockwood
Thanks for the info. Interesting reading. Seems these days, a good one is hard to come by.
Kiwi Kev

[brockwood]

Hi more stories some funny habits what looks like the clutch peddle is the inching peddle this actually puts the trans in neutral and can be used to cushion changes tho hard on bands funny thing is when put in gear with inching peddle will for a start roll in other direction so many have dent from front of shed. you can and are meant to just flip into a low gear will give a grunt and move off then up shift .to stop close throttle skip down thru gears and when at low speed straight in to park remembering that in this case its a soft clutch relatively )engaged not a fixed gear like a car .we drove ours like this with no brakes for 20 years with no probs after initial design faults of cause these tractors were under tyred and ballasted when they first came out they only had 12 the later ones had 14 the dealers did a great trade in widening rims but even with weights would spin same with stopping just slid probably helped the trans im sorry to say we never trusted it so were relucent to spend money on it thou in the end it was the engine. Put rings in at one time was tow starting in the morning not supposed to be possible but turn over in high gear till it starts to creep take off with tow down shift til she hums lean up bonnet and a hit of start you barstard and away you go rest of the day all right they are about one on ebay at the moment .all bits avalable but finding someone to work on them can be hard b

[The Swanndri Guy]

Select-O-Speed, "SOS",Kev there was a good 4000 SOS on Trade Me about a month ago, don't know if it sold.Not very common in NZ, but from the ones I've seen are mainly 4000, not many left,most dismantled or converted to 8 speed. Locally there is the remains of 4000 and posabilly a 3000 SOS not too far away.My question in relation to Select-O-Speeds is, are they a development of the previous US Ford tractors or was the design all new for the World Series tractors? TSG.

[brockwood]

Hi from Stuart gibbards book the ford tractor story the Trans was released in the work master on 3 Feb. 1959. In 1961 fordson built an experimental super major with select o speed from a 6000.but it wasn’t preceded with b

[5000blues]

Thanks brockwood,
now I know why the nose cone on my 5000 has so much polyfiller in it!!
My sos 5000 was converted to an 8 speed box long before I got it. I still have the 30:1 ratio back end, and the four holes under the steering where the shifter was mounted.
I was very tempted to buy an old sos gearbox that was on ebay a few months back, but if I did get one how do you go about testing it, replacing bands, o-rings etc. I think there were a lot more of them in the USA, mine was bought new by an American who had a farm in Co Galway in 1965. I bought it in 1987 and it is still in everyday use.
Classic tractor magazine did a few articles on them, I think they said that the specs laid down by the guy who designed the sos gearbox weren't followed (ford cost cutting? ), and he left and went to work for john deere where he perfected the power quad gearbox. I have only ever seen one sos ford 5000 in Ireland, and that one was imported from Holland.

[Brian]

Select-o-Speed were a very good box in the right hands. At the time there was nothing like it on the market and it suffered from abuse and operators mis-understanding of how to use it.

Fords did not help either as their demonstration of the box at Boreham and at the dealerships was to drive a tractor at full speed in tenth gear then go straight to reverse, the tractor would still be travelling forwards with the wheels going backwards.

Of course some operators tried this "at home" and wondered why the torque limiting clutch flew to pieces.

The other problem was failure of No.1 clutch pack due to the constant use of the inching pedal. On early transmissions in the "X" series tractors, use of the inching pedal diverted oil flow from this clutch pack leaving it with minimal lubrication. It was eventually sorted out but, by then it was too late. This should have been noted in the early use of the box in the US.

To me, it emphasises the differences and problems in building a "World Tractor". Testing and sales on farms in the US did not show up the problems that occurred in European use. This would not be the first or last item that worked well over there yet would not perform in our conditions. Early Axial Flow combines are another example.

As I have often said, we sold 27 Select-o-Speed tractors at a time to a big local farmer and the staff loved them. Problems were non-existent but they were well serviced with regular oil changes and band adjustments. It was a pleasure to watch the operators use them. One man in particular had a Cameron-Gardner loader on a 5000 that loaded the sugarbeet into lorries, you could not notice him change direction when doing this, it was so smooth.

[5000blues]

Thanks Brian,

there was an opencast lead zinc mine in galway that used about 8 sos 5000s for bringing the ore up. The big advantage there was the smoothness of changing gear over other tractors which would tear the gravel surface up. That was back in the late 60's early 70's, and I don't know where they went when the mine closed. Any idea where those 27 per year went when they were traded in?

[Brian]

Think most of them went overseas, Wrights and Does worked together when they got large numbers of second hand tractors in stock, to find export markets.

We also had the Doe 130 SOS which was some tractor! I have written about her on the Wiki in Memories.