2005 Buick LeSabre Transmission Problems :(

traxion02

Hi,

I have been having some trouble with my transmission hard shifting as I accelerate. It's been kind of weird....

2005 Buick LeSabre
185,000

The car sometimes will shift hard when accelerating.

It happened once a few months ago- I had been on the road for hours and it just decided to start doing it. Then when I stopped for gas, it went away as soon as I got back on the road. It didn't do it again for months.

Lately it had been doing it more, but it would be the same thing. It wouldn't start until I had been driving for a bit, then when I shut it off, it would go away immediately.

I had the transmission flushed and cleaned, and now it seems to be doing it more often.

Sometimes I can go an hour and get to where I need to go without a problem, other times it happens 30 minutes down the road. It has never done it immediately after starting my car, it usually takes at least 20 minutes to act up.

Any ideas as to what would cause this? Any help is greatly appreciated.

countmein

My 2005 buick lesabre has the same problem. I changed the solenoids, and it helped for a little while. Now its back. Mine has 176,000. It has been doing this for 4 years now.

imidazol97

traxion02 said:

It happened once a few months ago- I had been on the road for hours and it just decided to start doing it. Then when I stopped for gas, it went away as soon as I got back on the road.

This is due to a weak pressure control solenoid. After the fluid warms up and becomes thinner, it's not able to provide enough pressure at lower rpm for a good shift. If the computer senses a shift is too long two times, it sets a code and goes into a quick shift fail safe mode avoiding slippage.

When you shut the car down for a short time, the computer resets on restart. IF you keep your shifts at higher rpms by accelerating harder, it often avoids the slippage during the shift when the fluid is hot such as in slow city traffic and higher ambient temperatures.

I also have used manual shifting to control the rpms and shift at higher rpms like 2000-2200. There are shift kits from a couple suppliers that change the springs in the valving and give a quicker shift. The 1-2 and 2-3 shifts are controlled by a unit accessible from under the car when changing the filter. The 3-4 shift, usually less of a problem, requires removing the side plate. That's hard to do and more expensive. Depends on how much of a do-it-yourselfer you are or if you have a shop that will install the kit springs and travel limiters on the underside of the trans inside the valves that hold fluid to help during the shifts. I'll post more about those if I can find them again.

Most trans shops see 185 K as overhaul time. They have that yacht payment and summer home to keep up.

TurboJeffy86

I have the same issue with hard shifting occasionally. I heard a T 65 solenoid replacement will fix..? I'm only at 81K orig. On this 2000 LeSabre. And what is the proper name for this solenoid please?
Thx

imidazol97

https://tripleedgeperformance.com/Harsh-Shift-P1811.html

Since the code set is P1811, searching for that along with T65 or lesabre will bring up lots of "help." Some knowledgeable, some not so knowledgeable.

The real solution is to replace the transducer valve which has worn the walls of its location. I may not have the right name--a quick search couldn't find it. If I recall the piece for fixing may come from someone like tripleedge performance and is slightly oversize. So requires reaming the cylinder to get a tight fit again. Sort of like the morning sickness problem in power steering racks long ago.

https://buickforums.com/forums/threads/transmission-code-p1811.30617/

This discussion may help you.

Changing the springs on the tripledge kit parts is a band aide that can be put on taking the drain pan off. And helps most people. Fixing the problem essentially requires rebuilding trans and if you go to that trouble of getting at the pressure control solenoid (I think that's the name of the part that wears), you should invest in doing all the replacements in a rebuild and bring it up to date. Often a lot of expensive for a car that's not worth as much being put into it.

Band aides can last a long time... especially if you understand that letting up slightly on the gas during the lower shifts keeps the wrong pressure from giving too long a shift time which causes the computer to go into high pressure mode to force the shifts quickly to reduce slip.
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Good luck.