1992 Rodeo trans slips into neutral

[TobyU]

I have a 1992 Rodeo 2wd with the GM 3.1 in it.
It has 89,000 miles on it. It has been slow to go into drive for a while now.(auto trans) When you shift into reverse it goes right away, but when you place the shifter into D it takes a 2-3 seconds before it actually goes into D.
I dropped the pan and changed fluid and filter and it did not seem to help. Now it is starting to go into N when taking off from a stop. It only does it when cold...About 15 degrees here now.
If you stop at a stop sign and then go to take off, it is like it is in N and then pops into gear hard..
I dod't know much about tranny internals..I was thinking possibly a low band adjustment problem or I have heard of a "front pump" causing no go problems when cold...
Any band-aid ideas..or what I looking at...BTW is this the same trans as the 4wd or not.
Thanks for any help or ideas...

[silky4u]

Thats an odd one. I know this is a stupid question but how is the fluid level. I only ask this because i must, a transmission may not be able to gain enough pressure (or gaining it too late) in order to apply the band or clutch pack. I'm not familiar with that tranny's powerflow so i dont know if 1st gear is applied by band or clutch pack so i will be vague. If it is a band i would guess that it could be a faulty servo or a semi-plugged servo. This would explain the late shifting, dirt and debris from friction materials in the tranny or sludgified tranny fluid could cause and obstruction in a hydrualic control path. After a couple of seconds fluid pressure is finally reached and the servo is applied. Or your front pump is faulty like you said and at low speeds it may not be able to create the pressure to apply anything, clearances in tranny pumps are very critical, if other gears shift fine i would guess that this is the culprit. Only because in other gears the same holding members that are used in first may be applied, specifically in final drive. Sorry for being so long.

[TobyU]

Thanks for the reply....I also noticed tonight it does it in reverse also.
If you take off very easy it is fine....if you go for a quick take off in d or reverse it is like it is in N then it kicks in hard..
Once you are moving, it is perfectly normal feeling..
I keep thinking it is a band that is loose....doesn't the same band do low and reverse in most trans?
I am not sure about this 4L30E.

[TobyU]

Oh BTW the fluid level is fine. That was the first thing I checked. It feels like a fluid slosh condition but it is slightly above full.

[silky4u]

In general , or most of the auto tranny's that i have seen, low and reverse are activated by the same band (thats why reverse and first have closesly related gear ratio's. I also know that if too much fluid is added you can get the airation of the fluid, which can cause the same effect as a low fluid level. A band is easy to adjust, so give that a shot and if that doesnt work i would suspect the pump.

[TobyU]

Thanks. I am lookng for info on adjusting the lw reverse band,.... I think it is in the larger pan.