antmang

I have a 1993 pickup, automatic 4x4 with the 3.0 engine and A340H transmission. Just purchased the truck and the first time I lock the hubs and put in 4H or, 4 anything, the transmission seems to dump (or spray) the entire fluid capacity of the transmission. The leak (dare I call it) looks to be coming out of the top of what I believe is called the Extension housing? at the rear of the transfer case... perhaps it is a blow by valve? Are there any links to diagrams that will tell me what all the parts are to the transmission/transfer case? Any troubleshooting guides? There are no visible leaks when the 4x4 is disengaged and driveing in 2wd but comes out like a gallon every 30 seconds when engaged.
Secondly may or may not be related.. the front 4x4 axles have just been replaced and when driving in 4x4 and in 4h every revolution of the wheel I get a thump... doesn't happen when driving 2wd and manual hubs are engaged... or disengaged. Thought perhaps one of the axles was damaged during install but would think I would hear noise when in 2wd and the hubs are engaged as the axles are turning with the wheels? Any help or comments appreciated!

scope103

The A340H "comes with" the transfer case. The transfer case is itself a small automatic transmission (using planetary gears, etc.). I understand that the hydraulic pressure for the transfer gearing is from the pump in the main transmission. This could explain why you are pumping out hydraulic fluid only in 4H and 4L.

Let us know what you find.

http://personal.utulsa.edu/~nathan-b...autotrans.html