Tranny slipping or TQ?

[98SE]

Ok so here it goes. I have an 88 SE-V6 4x4 with the 4 speed auto. For the past 2 months, the transmission seems to have trouble locking up in 4th. It shifts between 1st and 2nd very smoothly, third can be slow but I hear that is common on these transmissions. Shifting into 4th is also very smooth. But when I am on the freeway going 70 mph, it doesn't seem to lock up, it spins about 3100 rpm, if I give it gas so I can speed up it revs anywhere between 3000 and 4000 rpm but doesn't gain any speed. If I give it even more gas, it then will immediately downshift to 3rd and accelerate just fine. Keep in mind there is no hesitation when it downshifts. I'm having touble trying to figure out what the problem is since it only does this half the time. The other half of the time it does lock up and it will spin about 2650 rpms at 70 mph. It only has this problem when in 4th gear and it applies to any speed. Typically I've noticed that it doesn't lock up when the temp is below 50 outside or if there is even the slightest amount of wind. It it is above 50 degrees, it usually locks up. Do the torque converters in these lock up? I'm not sure if my torque converter is failing or my 4th gear is slipping. Also, I still have reverse and it works just fine. I know some of you are gonna ask if I have bypassed the cooler yet, and the answer is no I haven't done that yet. I did flush the fluid recently to see if that would help this problem (and it didn't) but I did not drop the pan and change the filter. I'll probably wait till next month or so before I add the cooler and change the filter since I hardly drive this thing. When I changed the fluid, the stock cooler was still flowing plenty but I know it is still crap and I need to bypass it since I do get heat coming from the center console. So down to the point, should I try changing the filter? Or is my tranny just going out? If so I need to sell this thing before it does.

[Slick]

sounds like the TQ is goin south.

[adamzan]

You say if its below 50 degrees it won't lock up, how long are you driving it for? I know in my 95 here in canada the tq won't lockup unless the truck is FULLY warmed up, like temp gauge where it usually is and heat flowing full.

[98SE]

You say if its below 50 degrees it won't lock up, how long are you driving it for? I know in my 95 here in canada the tq won't lockup unless the truck is FULLY warmed up, like temp gauge where it usually is and heat flowing full.

 

 

I've driven it as far as 87 miles when it was 36 degrees and the tranny never locked up.

[jpawela]

I've driven it as far as 87 miles when it was 36 degrees and the tranny never locked up.

 

Wow. That's far. That can't be good on gas. My 95 w/ 98K has the same symptoms too. Only it locks up at about 7 miles down the road, regardless of temp or weather conditions. Mine feels like it's literally slipping—it will lock, then unlock a few times before settling down. Like it can't make up its mind. Another member told me that a complete tranny flush solved this, but it could open a door for some new problems. I'm considering it anyway since my shifts are quite hard.

[Kittamaru]

jpawela, try activating your cruise control and bumping on cruise at 35 (the minimum speed you can) then accelerate and hold her steady manually- I've played with it and it seems to make it lock in faster/sooner, no idea why, possibly a fuel saving thing.

[jpawela]

jpawela, try activating your cruise control and bumping on cruise at 35 (the minimum speed you can) then accelerate and hold her steady manually- I've played with it and it seems to make it lock in faster/sooner, no idea why, possibly a fuel saving thing.

 

 

Only if my cruise would work...

[adamzan]

Only if my cruise would work...

Same here

[02silverpathy]

Please try Lucas Tranny Slip Fix...My 01 Alty was a hard shifter and would wait for higher than necessary RPM's to bump us into the next gear....this was at 70K. I have since added lucas for about 5K, done a home drain and refill adding Lucas again, and just last Summer another drain and refill with Lucas again. I have spread this flushing out over the last 20K in 1.5 yrs and could not be happier. The tranny is responsive, shifts correctly and is even timely and accurate when you are getting on her!

 

I put this same fluid in my 02 Path, I have noticed very little difference at 50K, but it does fall into lock up with more ease. My tranny has an issue with clmbing semi steep grades and letting go of 3rd, as if it needs a re-flash concerning throttle and acceleration***disclaimer for that is I have 32's on it compared to the stock 29's and m-a-y-b-e the tcm thinks it still needs more rpm's to go to the next gear...my re-gear is on the way!

[98SE]

I changed the fluid a little while ago and added lucas trans fix but it didn't help the problem at all. It did however make the shifting a little smoother.