I have a 1998 Buick Lesabre with 120,000 mile (4T60-E I belive). I have every receipt for every maintenance done on the car, and it has had its trans serviced at least 3 times in its life. Plus I did a pan drop and filter change over a year ago (about 10,000 miles) and the fluid is still light pink. I tell you all of this because I believe I have a bad pressure control solenoid (PCS), as this seems to be a common issue on this trans.
My symptoms are If I get on the gas to hard from a dead stop, I get a lot of chatter (shaking the dashboard chatter). Also I get an occasional (a few times a week at most) flair on an up shift. This seems to get worse after a long drive (when the trans gets fully warm), Or as the temp goes up. I have learned to roll into the throttle, and not jack rabbit start, so I rarely feel this chatter anymore and honestly it’s not a big deal to me at this point.
However I want to know how long do you think the trans will last like this? Is it something that can get worse??
Reading online, it looks like to replace this $40 part I would need to either a) drop the entire trans, or b) tilt the motor trans combo down so that I can pull off the side pan. This is probably beyond my weekend skill set, as this is my only car, and a shop is going to cost an arm and a leg. Do you have any simple way to fix this??
Thank you in advance
PS I did add a can of seafoam when I did the pan drop last year, and I think it did make a difference. I am planning on another pan drop shortly, any issue with using seafoam again?? Do you have another suggestion?
I’m not mr. transman. But those transmissions are way complicated. And I’ve seen a lot of people describe PCS problems and none of them sounded like that.
So…I think you’re going to have to actually cough up the change to have someone put it on a scanner, check out all of the e-controls, and check what is going on with line pressures & such. You really don’t want to go through the trouble of getting to that side cover on a guess.
The computer can easily have error codes for the trans stored in there without ever “telling” you about it via the check engine light. Ask me how I know…I guess GM thought this was an amusing thing to do?
That transmission might still have had a vacuum modulator on it to deliver the info about throttle & engine load. If yours does, those do create all sorts of issues when they have a problem. I can’t tell you exactly where it is if you have one, but its on the transmission someplace & will have a vacuum line attached.
That launch shudder you are feeling is more than likely from the low sprag. I’ve changed quite a few of these in the 4T65E’s over the years. When they go, they go. That alone will cause you to have to tear it down because if it comes apart it will be all over the pan.
The flare you are feeling, does it flare in each shift ex. 1-2, 2-3, 3-4 or does it do it in one particular shift?? I am trying to decide whether they are related.
With the PCS (Pressure Control Solenoid), they are an issue in these transmissions (4T65E). When I change these, I usually kick up the pressure a little bit since they are adjustable. There is no simple way to replace these.
Here is a pic of the low sprag and PCS on your trans.
As far as additives, use the Berrymans B-12 and the Lube Gard Red.
I think the flare is mostly in the 3-4 shift… When I took the pan down, I did not see chunks of anything, and I dont even recall seeing any metalic residue, and the trans was doing the chatter back then (one of the reasons I dropped the pan in the first place). So if the sprag was bad would the trans still be shifting smooth (97% of the time) over a year later??
Thanks agian, and thank you cigroller for your input as well
I forgot to say that, if I put the shifter into 1st I will not get the chatter anymore. I have read that this is because it put max line pressure on the first gear clutch pack and bypasses the PCS. does this make sence?
It still sounds like that sprag is not holding. If it comes apart, you’ll have to drop it into L1 to launch. I would love to know line pressure/line rise and test results of the PCS. Any chance of getting anyone to check it??