Hi all!  New to the site,thought I’d try to pick up some good info here seems like the right place to be! Recently purchased a D4d serial #78A7492 Tranny Group 5k8017 runs well but was wondering about the model year . It will go in reverse only F/R lever  stuck Should I pull the inspection covers for the steering clutches or am I barking up the wrong tree! Any help would be greatly appreciated!

could be just stiff mechanisims. try some penertrating oil on the linkages.

Not sure about a D4D setup but I assume there is an interlock with the cluch lever to lock the transmission in gear when the clutch is engaged. I would start by making sure that is working correctly.You really need a servicmans reference book for that model or at least a copy of that section.

Hi, TomsD4d.
If the F/R lever is STUCK in reverse, I would look first at the interlock mechanism that wimmera farmer mentioned but I would also check to see that nothing become wedged in there somewhere to jam the lever - although I think that control goes straight into the transmission case with no linkage.

How-wevver, if it comes out of reverse to neutral but will not go into forward, that may well be something inside the transmission, although not entirely ruling out the interlocks there either.

Just my 0.02.

Just my 0.02.

The 78A prefix approximately starting shipping out in 1963. So #78A-7492 is most likely 1963-1964. Best I can do

If a 4D trans is anything like the 6C, the interlock mechanism consists of a cover holding a shaft and a series of springs and plungers. No huge task to remove and clean up, but depending on the configuration of your tractor, may be a pain to access, like the one on my 6C. A broken spring or plunger could hang things up