Engine/Transmission (1998.5 - 2002) General auto trans question

[plongson]

I have general automatic transmission question.



What would cause a transmission to not shift 2nd to 3rd when cold but as soon as it warms up, usually 5+ minutes or several miles... it will shift perfect.



It basically just stays in 2nd until it warms up, no matter what I do to coax it.



This is on an old 1984 Jeep with a 904 torqueflite.



Is there a easy fix or am I not going to like the answer...

 

[Joe Mc]

Not real familiar with the 904 TF. But, have you serviced it? I. E. fluid/filter change and adjust the bands? I think this is a vacuum shifted trans? If so, there may be a vacuum leak somewhere that seals itself up once things warm up. Finding that leak could be a fun thing. Once again if shifts are controled by vacuum it could be the modulator on the trans, last time I did work with a vacuum shifted modulated trans the modulator was adjustable by removing the vac hose and inserting the right size allen wrench - I did a 1/4 turn on the screw one way and test drove to see if that made a difference then determined which way to go based on what I was looking for. Best to go in 1/4 turn increments if it's adjustable. Check a shop manual and see what it says . . . Hope this helps a little bit, sorry not real familiar with the old 84 TF trans.

 

[plongson]

I just bought this little Jeep and it looks like the transmission has been out sometime in its life. The oil looks real good ie. not burnt, nice and red etc. It actually looks like new. Oh, I was wrong it is a 909 TF, I guess that just means it has a lock-up converter. I going to check out the modulator as you suggested. Is that key to the 2-3 shift??



Thanks!! Paul...