4T65E Trans Shift Hard, P1811 DTC

[enslow]

ok, I will not be able to remove the side pan without separating the left side of the cradle from the engine. At least, on this car, there is not enough clearance between the side pan and cradle to slide it out. I could probably change the solenoids out now, but I'd feel much better with the new side pan gasket I already have, plus the ability to clean things up before re-installing.

Now I have to locate a 3 arm engine support.

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[enslow]

For those of you considering doing the shift and PC solenoids on a Lesabre, get a 3 point engine support bar and two lengths of 5/16 grade 70 chain. This will allow you to raise or lower the engine independently of the subframe. For some years, makes, or models you may be able to do this job by lowering the engine and sub frame together, but not on mine.

I got the two shift solenoids, pwm solenoid, and the PCS all done. I've got the side pan back on and am working at getting the engine and sub frame back into place.

On a side note, for those of you who are crazy enough to drop the sub frame, paint a little POR 15 on the frame where the sub frame mounts. This may slow corrosion.

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[snecky]

Hi , I have a 2000 buick century 2000 with about 54000 miles .A couple of days ago we were in the mountains driving 4up fairly quickly with no problems . After returning home and having dinner we decided to go out to eat . We drove on the interstate and after a few miles the car starting shifting really hard . We pulled off the interstate and stopped for about an hour. Once we started again the car shifted normally . I had the trans fluid changed ( fluid only no filter ) a couple of weeks ago . Since then no problems .Researching I came across this thread . Should I go the shift kit route ,or is this appear to be a once of event . Thaks . Rod

[enslow]

l tried the shift kit and it didn't help. For others, it did. I suppose it's worth trying, but be prepared to replace the solenoids.

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[vsuper]

you all can replace all that stuff fluid, solenoid valve, shift kit, or whatever.
But the problem is in the tranny .

The2nd gear clutch is bad in most of these. if your dipstick has some black on it. It is from the 2nd gear clutch pack wearing out

NHTSA has a service bulletin out # 10020766
1st -2nd shift shudder replace complete 2nd clutch assembly

and info on valve body recon bulletin #10025065 for harsh shifting or slipping

[enslow]

FWIW, I haven't had a single shudder since I replaced the solenoids.

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[la1]

I have to say I was experiencing harsh shifts after running awhile and maybe 2 - 3 times a month a thump like the trans was shifting when starting out. My downstream ox sensor failed ( CEL on with code) I installed a new one, a lot of the harsh shifting and random thump went away. I cleaned the other ox sensor with sensor safe TB cleaner. Now the trans works perfect. Maybe the downstream ox just needed cleaning. Glad I kept it, will try sometime. No codes or pending codes, only when the downstream ox failed I got a code.

[enslow]

This illustrates the necessity for proper diagnosis. A harsh shift is not necessarily caused by a bad clutch, but it could be. I'm glad la1's was easy to fix. I figure I went as deep into a tranny as I'd want to, so I'm kind of lucky too.

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[la1]

well maybe I might have been too quick to judgment for the harsh shifting. It is still cold here and my version of harsh shift usually happened during a long drive in hot weather. I could get it to go away by merely turning off the ignition and back on again. The harsh shifts did happen rarely around town. The ones around town disappeared so far. The main plus was the false shift after going a few feet was gone. I clean my MAF and all the sensors...never did the OX though till now. My sister has a Nissan( 3 cars since the one above) that 60% of the time the car would start off in second gear . I cleaned her MAF with sensor safe TB CLEANER. problem alleviated. Her MAF was one of the clear film types. I always thought the harsh shift on 4T65E's was due to the PCS leaking fluid past. The PCM would see a drop in line pressure and command higher pressure to save the clutch pack. The higher pressure causes the harsh shift.

[MN_Max]

What is the brand name of the shirt kit (if you don't mind BNailer) and can I drain the Tq. converter on my 4T65E transaxle?

[la1]

UPDATE, While trying to find the source of an oil leak ( either LIM or oil pump drive/distributer blank) I removed my TB ( throttle body) the 2 bolts were real loose and the gasket was like a sheet of plastic and showed signs of leaking. Really improved performance and have not had any harsh shifts , just good clean trans action. here is the link to the vid I made
https://www.youtube.com/watch?v=OLS_Y_MDnJE

https://www.youtube.com/watch?v=OLS_Y_MDnJE

[bjbrown]

Wow, what an informative thread. Thank you so much. I sure wish I had read this before I put $1800 into a rebuilt trans for my 1999 Silhoutte, which had a bad slipping problem since bought it from my Uncle. He was unable to get the Olds shop to deal with it, since it came and went. Rbuilt unit .... same problem. So the shop that sold me the rebuild put another rebuild in .... same problem. They then told me to go away and not come back, that the problem was sensor related somehow, told me to try an electrical shop. (Jesse Lewis was the shop, they are good, just not as smart as the experts on this thread!)

Anyway, now my 2001 Silhoutte is acting up, albeit more violently. Not slipping like the 1999 is wont to do, but rather shuddering at 40-45 mph, on the upshift, feels like it might come apart! My brother thought it a broken motor mount (no), my dad a half shaft (dont think so) the guy who sold me tires thought it wheel bearings (changed out perfectly fine bearings) and another tire mechanic said "bent rim." Nope.

SO ... I will soon try the Sea Foam and Dex IV. I am a half way (or is it half assed) DIY er ..... should I attempt the shift kit changeout? Can I buy one from the local autoparts stores? Should I just try the Dex 4 and Sea Foam first, and then, if that is not enough, go for the shift kit attempt? I do have a wrench twisting brother who bails me out if (when) I get in over my head.

Advice?

Thanks! Bryan

[Tech II]

Doesn't anyone ever go for a test drive, with a Tech II in snapshot mode anymore?

[bjbrown]

Originally Posted by Tech II

Doesn't anyone ever go for a test drive, with a Tech II in snapshot mode anymore?

Eh? I do not follow?

[enslow]

Originally Posted by Tech II

Doesn't anyone ever go for a test drive, with a Tech II in snapshot mode anymore?

That would make diagnosis too easy and quick. They wouldn't make as much money on customers coming back a dozen times to solve a problem. I'm not sure what it's like elsewhere, but I have yet to find a shop that can find regular normal problems quickly through systematic diagnosis. I'm a DIY, not a pro, so I'm not exactly systematic either. But I'd expect some one with years of training, experience, and tools I can only dream of owning, they can diagnose better and faster than I.

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