I’m looking to buy a 1977 941B that has done just over 6000hrs and is in overall excellent condition, but after having moved the machine backwards and forwards I noted that all three gears in reverse are fine, in forward you cleanly get first and second but the machine stays in second when third is selected. 
The machine has been underused recently so I’m hoping it’s an adjustment issue or a sticking valve or something? Overall the machine is in excellent condition but wants a full service as ex farm. There is a top roller that’s reluctant to turn and the radiator is a bit cruddy but it’s probably one of the better ones out there. 
Steering, undercarriage and transmission (apart from the third gear) seem really good.
Any ideas?

Hi, PeteRE22.
Does the transmission control feel to have a lot of wear in it and does it 'click' into the 3rd position on the forward side? If the answer to the first part of the question is, "yes", and/or the answer to the second part is, "No", that could be your problem - just not pulling the lever on the transmission far enough through its stroke to click into 3rd on the forward side.

If neither of the above apply, look for any obstruction to the linkage than might be holding it out.

Those transmissions use the same speed clutch packs for both forward and reverse and simply engage the forward or reverse clutch depending on which side you select.

The 941s are a solid machine.

Hope this helps.

Just my 0.02.

I agree with Deas. If the transmission shifts into 3rd reverse is okay then not going into 3rd forward is simply a linkage problem. Just adjust or repair/replace whatever is wrong with the shift linkage and you should be fine.
The powershift transmissions are incredibly simple. They consist of 5 clutch packs; forward, reverse and 1st, 2nd and 3rd speed clutch packs. These packs are hydraulic(oil pressure) controlled. There is nothing mysterious or complicated about powershift transmissions. I have personally rebuilt 4 powershift transmissions; one in a D6C, two in D6Ds and one in a D6H LGP. All that is necessary is a service manual and the parts needed.
Craig

Thanks fellas, I appreciate the advice.
I’m going to go ahead with the purchase because she’s too good to pass up!
All the best 👍

Hi, seiscat.
I am NOT a mechanic but it is my understanding that there is one further NECESSITY for rebuilding power shift transmissions - close to operating theater standard cleanliness. Please correct me if I am wrong.

Just my 0.02.

Hi Deas,
The necessity for cleanliness when rebuilding a powershift transmission is the same as an engine rebuild. Neither one does well with a hand full of sand! lol!
Craig

Hi, seiscat.
Wunnsa ponna time, there useta was an Australian tractor and farm machinery manufacturer named Chamberlain Industries. Their first tractors, back in the very late 1940s-early 1950s were gasoline start-run on kerosene, horizontally opposed 2-bangers around the 40 - 45 HP level. They had an EXTREMELY strong transmission and back end, so strong that you could convert them to an 80 HP diesel with no problems.

The point - it was rumored that you had the throw a handfull of gravel into the transmission and back end to help them 'bed in'.





which went to this:



and then this: (made by a South Australian farmer, NOT by Chamberlain but based on Chamberlain tractors)



Just my 0.02.

A lot of people adjusted the linkage so that you could not put it in 3rd check linage

Hi, tmoline.
Yep. a lottta people did adjust the linkage - or put a block there - so that you could not get 3rd. But I suspect that if you can get 3rd in reverse, it also oughta be 'gettable' in forward 'coz the only thing that would be different would be the direction selector position - unless some smar tass invented a set-up where by he/she/it could use the direction selector to lock it out of 3rd forward.

Just my 0.02.

My 941B has a bolt installed to block it from going into 3 rd gear---was that way when i bought it in 1989