Tranny Problem???
 

On the wifes 97 4X4. Doing 45 MPH +- The trans seems to slip back and forth between 3rd and over drive. It done this for the 3 monthgs ive had it. Now yesterday EMTREMLY cold here when we first take off Reverse slips. Until fully warmed up. Time for rebuild??? Duhhhh 160K

Make sure fluid level is correct. If it is a little low it will lock and unlock the torque converter right around that speed. It's a starting point at least. Make sure lfuid level is checked with engine running and at operating temperature.

Ill Double check when it warms up. This spring! LOL

Im must not know how to read my DIPSTICK Jimmy!!! LOL If I checked it once ive checked it 20 times. 2 Friggin quarts LOW. Jimmy!!!!!!

Now you can ask yourself where that fluid went. You'll probably find it in the transfer case, and some of it in the HVAC lines.

HVAC lines???? Sorry please explain. I thought the transfer case was a sealed unit. Thank you for reply :)

Ahhh need to clean out HVAC lines and transfer case and install new seals.

Yup, thats where mine goes. Gonna need to drop the transfer case this summer and replace the input shaft seal. Then im going to eliminate the vacum system from the front axle and install a cable. My tranny fluid would disappear and i could not figure out where it went till i started reading these threads about the No 4x4 posts and found out that the fluid winds up in the transfer case and all the vacuum lines.

If the seal between your transmission & transfer case goes bad, it will let transmission fluid go into your transfer case and will overfill your transfer case. If the vacuum switch on top of your transfer case goes bad it will allow the transmission fluid to be sucked into your vacuum lines which operate the 4WD actuator & HVAC controls on your dash. If this happens you should replace all of the vacuum lines. This does not seem to that rare of an issue. I just replaced all of the vacuum lines in the engine compartment, vacuum switch & seal because of this problem. Hopefully I won't have to replace the vacuum line inside the dash.

Had to make you do a little searching first. I think the ATF might be part of the reason the transfer case vacuum switch fails as well. I've had to replace my transfer case seal. I wish I had known about it back when I had the transmission out the first time.