Shuttle shift transmission problems

[darsstars]

Its been a while since I logged on here, mostly because I felt somewhat alone with my German JD 3400. I am sure there are a few still out there, should be mort cause they do so so many things good !
Now , here is my problem if anyone is listening who has an idea i welcome the mystery.... My 3400 has a shuttle shift trans. ( ZF ).that has started to slip in gear , sometimes a lot, . We checked trans pressure 200PSI rear, 100PSI front. So, rather than spending 10 grand, which I don't have right now, I decided to try changing fluid and adding Lucas Booster and Stop Leak. First I changed filter ( which looked very clean inside can ) then dumped what I thought would be 5 gal. of Trans. hydraulic oil.
What came out was 2 gal. total ! , yet the dip stick shows overfull ! ....so I proceeded to pour in new, strange thing only 3 gal. and I was showing over full again ! I took it for a spin around the driveway a bit , no slip , then tested again 3 gal. still showing on dip stick.I also had quite a bit of foam on dip stick. Waited an hour , checked it again, still same. Anyone know whats going on ? The book says 5.1 gal . I can only get 3 gal and start showing overfull?...strange.

 

[Tx Jim]

No model 3400 tractor shows up on JD's website. Foaming oil usually indicates a leak on suction side which introduces air into oil.

 

[darsstars]

It sure does , not current as they stopped making them 5 years ago., but go to JD Parts and type in 3400 , comes right up. I know , the fresh oil was only in the trans for 15 min. when I shut it off to check dip.....and I see no leaks ether side, I must be missing something? Air lock ?

 

[Tx Jim]

I guessed I overlooked it the 1st time I punched it in. Danged old timers disease I guess. Advertised oil capacity of trans & hyd systems are advertised as total dry amounts which is hard to attain a totally dry system once oil has been added and circulated in the system.

 

[jd110]

Wish I could help, but looking at parts diagram, it doesn't appear to be related to any model sold here in US. I didn't see any mention of shuttle shift in parts catalog either. Does the shuttle shift work without using clutch? Is there a suction screen in transmission that could be clogged? That could produce foamy oil also. Since pressure is lower in forward, that would point to a leak in the forward clutch.