2000 Pontiac Grand Prix Hard Shift Whine Fix

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WEAREA2J2
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I have a 2000 Pontiac Grand Prix 111,710 miles 3.1 liter engine, and 4T65E Transmission. The car emits a loud whining sound and shifts HARD after moderate to hard acceleration and after cornering. I shut the engine off for approximately 1-2 minutes and it acts fine until the next corner. It then resumes the action stated above again. It sometimes will do this during normal driving. What could be causing this? A sensor or something to do with the transmission? Any help would be appreciated.
Apr 3, 2006 at 3:10 PM
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KENB79764
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check motor and trans mounts sometimes they can let the engine shift and put a bind on the axles, cv joints. also check cv joints for binding.
Apr 5, 2006 at 2:35 AM
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WEAREA2J2
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[quote:03e1d261fe="kenb79764"]check motor and trans mounts sometimes they can let the engine shift and put a bind on the axles, cv joints. also check cv joints for binding.[/quote:03e1d261fe]

The engine does move slightly when I put the car in gear, but there is no excessive movement like when a motor mount is bad. The whining is coming from the vicinity of the torque converter, and does not start until the car has been run for a while. The transaxle is mabey a pint overfull. Would this cause any ill-effects? I had the transaxle flushed with a machine approx. 41000 miles ago. The fliud is now slightly off-colored and slightly burnt smelling. Thanks in advance for any and all help you can give me!! P.S. Where is the drain plug in case I have to drain some fluid?
Apr 5, 2006 at 10:20 AM
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KENB79764
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you may have clutches starting to go bad in the trans then. there is no drain plug for the trans, you have to remove the pan to remove the fluid. you can get a siphon pump at most auto stores to siphon a little of the fluid out although overfill should not cause your symptoms, it is just hard on the seals etc.
Apr 5, 2006 at 11:58 AM
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WEAREA2J2
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[quote:e4de0ad525="kenb79764"]you may have clutches starting to go bad in the trans then. there is no drain plug for the trans, you have to remove the pan to remove the fluid. you can get a siphon pump at most auto stores to siphon a little of the fluid out although overfill should not cause your symptoms, it is just ha
rd on the seals etc.[/quote:e4de0ad525] Would a fluid and filter change help prolong the life of the transaxle? I really like the car and dont want to have to get rid of it! I was told there are solenoids in it instead of a valve body. Could they have anything to do with it? Or a bad sensor? I can rebuid a 4 bbl carb, but i'm guessing here! Thanks again!!
Apr 5, 2006 at 2:42 PM
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KENB79764
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a trans service may prolong the life. make sure you change the filter also and not just a quick lube flush and fill. also put a quart of trans x in when this is done, this is the only trans product i have found that will actually help.
Apr 6, 2006 at 1:11 AM
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WEAREA2J2
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[quote:3287f63f01="kenb79764"]a trans service may prolong the life. make sure you change the filter also and not just a quick lube flush and fill. also put a quart of trans x in when this is done, this is the only trans product i have found that will actually help.[/quote:3287f63f01]Where would I get trans x? This is a new product to me. FYI, the transaxle in ? has not malfunctioned today since the temp. has been down for the last couple of days. It only seems to fault after continuous driving or when the ambient temp. is up. I put a product called prolong in it when it was newer and it seemed to help smoothe it out for a while. Thanks again!!
Apr 6, 2006 at 11:19 AM
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KENB79764
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you can find transx in auto parts stores. the trans acting up worse with heat is another indicator of clutches. when you change trans fluid and filter, just add one quart of trans x and use regular trans fluid for the rest of the fill.
Apr 7, 2006 at 1:18 AM
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WEAREA2J2
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[quote:62bc4f9b6e="kenb79764"]you can find transx in auto parts stores. the trans acting up worse with heat is another indicator of clutches. when you change trans fluid and filter, just add one quart of trans x and use regular trans fluid for the rest of the fill.[/quote:62bc4f9b6e] Thanks, Ken. I'll see if I can find it and service the transax. I'll keep you posted. Would you be able to find at auto zone or advance auto?
Apr 7, 2006 at 1:12 PM
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KENB79764
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either
Apr 8, 2006 at 5:43 AM
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WEAREA2J2
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[quote:94586cceb5="kenb79764"]either[/quote:94586cceb5]I serviced the transaxle and it seems to shift and run better. It has only whined about 5 times since instead of daily like it did before. Thanks for all your good advice and i will keep you posted!
Apr 17, 2006 at 4:38 PM
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WEAREA2J2
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[quote:77d2481e9a="wearea2j2"][quote:77d2481e9a="kenb79764"]either[/quote:77d2481e9a]I serviced the transaxle and it seems to shift and run better. It has only whined about 5 times since instead of daily like it did before. Thanks for all your good advice and i will keep you posted![/quote:77d2481e9a]The transaxle in ? started acting up again. I took the car to a shop here in town that specializes in gm transaxles and he said it could be a factory defect with the pressure regulator solenoid! A week from tomorrow I will know for sure. I'll let you know.
May 3, 2006 at 3:48 PM
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BMOZOE
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We had the same problem with our 2000 Buick Century. A solenoid was replaced at 70,000 kms. The car now has 160,000 kms and the transmission is doing it again. I was told that GM knew that the part was faulty, but did not change manufacturers until 2003!
May 4, 2006 at 12:58 PM
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WEAREA2J2
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[quote:3d9af13942="bmozoe"]We had the same problem with our 2000 Buick Century. A solenoid was replaced at 70,000 kms. The car now has 160,000 kms and the transmission is doing it again. I was told that GM knew that the part was faulty, but did not change manufacturers until 2003![/quote:3d9af13942] Does it really surprise you? They got their money and can claim ignorance! I will get the transaxle checked out and keep you posted. Thanks for your input!!! When you wrote KMS, are you from overseas?? I spent 3 years in Germany. Just curious. Thanks again!! Ken has been a BIG HELP!! He let me know what direction to go. By the way, can you give me a ballpark figure on price of replacement?
May 7, 2006 at 2:49 AM
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BMOZOE
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3 years ago, we paid $2,200 CAD. Good luck.
May 7, 2006 at 11:51 AM
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WEAREA2J2
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[quote:8aa2d485b8="bmozoe"]3 years ago, we paid $2,200 CAD. Good luck.[/quote:8aa2d485b8] Thanks much for your quick response!!!! I hope not to have to spend anywhere near that. I have contacted GM with this problem and hope to have more news soon. I will keep you posted.
May 7, 2006 at 2:52 PM
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WEAREA2J2
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[quote:5cab5fb0e4="bmozoe"]3 years ago, we paid $2,200 CAD. Good luck.[/quote:5cab5fb0e4]I had the pressure control solenoid replaced today and the cost was not near what I feared it would be!! I ended up paying $480.00 total! The part was only $100.00, and the labor was $380.00. I still find myself fortunate. Ken, my mech. said that there was no metal in the transaxle and it appeared to be in good shape. THANKS ofr all your great advice!!!
May 11, 2006 at 11:54 AM
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Suggested Repair

Check engine and transmission mounts and CV joints for binding. Drop the pan to change the fluid and filter rather than only flushing; slight overfill is unlikely to cause these symptoms but can stress seals. Heat-related whining and hard shifts can indicate clutch wear or a faulty pressure control/regulator solenoid. In this case, a fluid and filter service helped temporarily, and replacing the pressure control solenoid resolved the complaint; the transmission had no metal and otherwise looked sound.

Conversation Summary

A 2000 Pontiac Grand Prix with a 4T65E whined and shifted hard after acceleration, cornering, or heat, then improved briefly after a short shutdown. The expert suggested checking mounts and CV joints, then suspected clutch wear and recommended a pan-drop fluid and filter service with a quart of Trans-X. Overfill was not considered the cause, and there is no drain plug. Service reduced the whining. A GM transmission shop suspected a defective pressure regulator solenoid; the owner replaced the pressure control solenoid for $480 and reported the problem fixed, with no metal found in the transaxle. Another owner reported a similar solenoid issue on a 2000 Buick Century.

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