05 Shifting/transmission Problems

[PGrotts]

I have an 05 Lesabre with 149,000 miles. Starting about 2 weeks ago it stared shifting from 1st to 2nd gear late and hard and occasionally it wont shift into 2nd gear and the RPMs will rev then when I let off the gas and push again it is stuck out of gear between 1st and 2nd and pushing the gas just revs the engine. Once the RPMs come down low it will shift in to 2nd. Has no other issues shifting from 2nd gear up through the rest of the gear box or any downshifts. There is occasionally the one day a week where the transmission runs perfectly smooth and none of these problems occur but these issues come up almost every day. Any idea if it is a computer timing or solenoid issue?

 

[Alan 55]

I have an 05 Lesabre with 149,000 miles. Starting about 2 weeks ago it stared shifting from 1st to 2nd gear late and hard and occasionally it wont shift into 2nd gear and the RPMs will rev then when I let off the gas and push again it is stuck out of gear between 1st and 2nd and pushing the gas just revs the engine. Once the RPMs come down low it will shift in to 2nd. Has no other issues shifting from 2nd gear up through the rest of the gear box or any downshifts. There is occasionally the one day a week where the transmission runs perfectly smooth and none of these problems occur but these issues come up almost every day. Any idea if it is a computer timing or solenoid issue?

Welcome to the forum! What has been the history of the transmission concerning fluid and filter service? What does the fluid look like on the dipstick? Black, brown, red?
Does the fluid smell burned? Sorry to ask these questions but this does make a difference in troubleshooting the problem.

 

[PGrotts]

Thanks for the reply! Fluid level, color, and service has all been normal. I do not know however the status of the filter or what its service history is but I am planning on changing it within the next week or so because I'm sure it hasn't been done yet.

 

[RobR]

Please dont take this wrong,but the filter is the least of your concerns. There are so many documented problems with these transmissions and they made millions of them. Google 4t65e trans problems and your head will explode. If you would like to take care of all the maladies of this trans,i recommend you do this.
1. Have the trans serviced. Dont do a flush. Drop the pan and drain,install new filter. DONT replace the gasket. Its extremely sturdy. Dont pay $70 needlessly.
2 While the pan is off,have new magnets installed per TSB# 08-07-30-040C
3. Also have the Transgo 4T65E Shift kit installed. Very simple to do while the pans off.
I had the same symptoms,and worse. Its smooth as silk now.
Heads up though. That slam -bang downshift 2-1 is worn valve barrels in the trans. You either have to open up the trans,put an additive in the fluid,or do what i do. Ease into the throttle when slowing to around 5-10 mph. Its something about giving time for pressure to build in those valves to complete the downshift. I cant explain it,but it works.

 

[imidazol97]

Because the transmission occasionally works smoothly from 1-2 upshift, if you do your own work
I'd suggest either using a siphon tube 1/4 inch that can go down the dipstick tube and siphon out
as much fluid into a bucket as will come (do when fluid is warm so its viscosity is lower and it flows
faster). Replace with Dexron VI and let the new 1/2 of the total fluid volume with fresh additives work
to clean up deposits and let any particles get caught in the old filter.

Then drop the pan after 400-500 miles and replace the filter and the 6 quarts of 1/2 old and 1/2 new
fluid. Refill with Dexron VI full synthetic and now you have 3/4 of the fluid being fresh and higher percentage
of cleaners and additives.

I'm wondering if the fluid in it is not truly compatible with Dexron IIIE, which I believe was the original specification,
which is now Dexron VI. I recall I used a name brand from Walmart that was Dexron/Mercon compatible to refill
through the siphon method and it changed my shift characteristics. It was supposed to be a replacement for the
Dexron III fluids.

So I quickly started removing that mix taking out 6 quarts at a time.

IOW, I agree with all the changes in the previous post, but I would work into getting to the shift kit by seeing if
I can get the transmission ungummed, if it is being affected by something or by a bad fluid choice by previous mechanic.

As you drain and fill, drive, and then drop pan and refill, if you get an improvement, that's good.

Good luck.

 

[RobR]

Whichever way you approach this,when you have the pan off do the TSB. The magnets are around $20.