tranny shudder fix?

97 lesabre, tranny shudders only sometimes going into 3rd and overdrive, not all the time, seems to be throttle position sensitive, no codes except map sensor, moderate to heavy throttle = shifts fine, seems to do it when slight throttle input but still not all the time. changed the fluid and filter already, no change. could it be a TPS problem thats not showing up as a code? thanks joe

The tps can cause this and not set a code, a full scan would help pinpoint the problem, also the trans could have internal issues.

few weeks ago the tps showed up on the scanner. the tranny wasnt downshifting into a "passing gear" but shifting in all gears just fine. we cleared it and it hasnt came back again. so i am suspect of it causing my shudder problem.

also the idle control valve numbers were up like it was compensating for something and raised idle to over come it. although idle was still around 700-800 rpm. i did find split vacuum lines and havent rechecked the idle valve to see where it is.

thanks joe

If the TPS is quirky( couldn't think of a better word ) this can cause all kinds of driveability issues..

The 1997 uses a 4T60-E, but it also has a newer style torque converter and at the time the new lock up strategy... With the new lock up the PCM can lock the converter at lower road speeds and allow for a given amount of slip under varying load conditions... If there are any issues with the TPS it can cause a lot of issues with the operation of the trans as the PCM may think there is xx% of load when there is actually more laod than the PCM is really seeing..

If you are throwing TPS codes I would tell you to replace the TPS and see where that leads you..:smile:

no codes except map sensor, moderate to heavy throttle = shifts fine

Code for MAP sensor. What is it? IMO best to resolve the MAP sensor issue first.

the code was low input for map sensor, i havent checked voltage at the sensor yet, just been driving it. did pull map sensor off and looks like someone has been in it before, looks like someone pryed the sensor apart and can see all "guts" in there and looks damaged.

i havent replaced the sensor yet thinking that it would only cause me to get a little less fuel mileage. but is that all it can effect or more?

with the tps, i think i can feel a very slight pulsing when driving slower speeds but it is so slight than my wife doesnt even feel it, and also looks like the tach is glitching slightly as well, but hard to see it while driving,lol.

oh, and other things i need to do as well is replace spark plugs, i just did UIM about month ago and havent replaced plugs yet.

thanks, joe

I had my map sensor fall to pieces too so I replaced it when I did the pcv valve.

Code for MAP sensor. What is it? IMO best to resolve the MAP sensor issue first.

That is definitely my bad as I did miss that...

I do agree that the Map sensor issue needs to be resolved first..

Judging by the last post I'd replace the Plugs and possibly wires along with the Map sensor..

97 lesabre, tranny shudders only sometimes going into 3rd and overdrive, not all the time, seems to be throttle position sensitive, no codes except map sensor, moderate to heavy throttle = shifts fine, seems to do it when slight throttle input but still not all the time. changed the fluid and filter already, no change. could it be a TPS problem thats not showing up as a code? thanks joe


If you find this happening more when turning from a complete stop or going up inclines from a complete stop you may be looking at a faulty PCS....Pressure Control Solenoid. This is what tells your transmission how much power needs to be distributed to the transmission. I had mine replaced
in my 98 custom last summer and it is a timely fix. It ran me $615 at $75 per hour.

Just make sure you have a trustworthy mechanic look at it and make sure he knows what the problem is before he digs in and starts doing unnecessary fixes.

Good luck and let us know the outcome :smokin:

If you find this happening more when turning from a complete stop or going up inclines from a complete stop you may be looking at a faulty PCS....Pressure Control Solenoid. This is what tells your transmission how much power needs to be distributed to the transmission. I had mine replaced
in my 98 custom last summer and it is a timely fix. It ran me $615 at $75 per hour.

Just make sure you have a trustworthy mechanic look at it and make sure he knows what the problem is before he digs in and starts doing unnecessary fixes.

Good luck and let us know the outcome :smokin:

The 1997 Had the older Transmission 4T60-E and did not use the PCS... 98 went to the 4T65-E

thanks guys, i have done anything to the car yet due to money situation. just driving for now. i seem to be able to control it with throttle input. i have gotten used to staying into trottle right about the shift point and it doesnt do it or if i im in city stop light to stop light i let off the throttle right before the shift and it doesnt do it. soon as i get some extra cash im gonna replace map and plug and wires and maybe a tps. will let you guys know, joe.

btw my clutch on the compressor started making noise recently. YEAH! :banghead:
if i turn on ac or defrost it stops that scraping clutch noise.

The 1997 Had the older Transmission 4T60-E and did not use the PCS... 98 went to the 4T65-E


Thanks for the info :cool:

97 lesabre, tranny shudders only sometimes going into 3rd and overdrive, not all the time, seems to be throttle position sensitive, no codes except map sensor, moderate to heavy throttle = shifts fine, seems to do it when slight throttle input but still not all the time.

My 2000 had exactly the same problem. There is a thread here somewhere. Anyway, new plugs and wires cured the problem.