Tranny "thump"

[SponsorMy95SC4]

My SC4 lets out a pretty noticable thump from park into drive or reverse, and vice versa, but only does it from time to time. Anyone else experience this? The car was at the dealership to fix the infamous power steering pump, and they also replaced a worn tranny mount, but said nothing about anything else. Just wondering if this is common. Thanks!!

[texsn95]

Yup, mine does it from Park to Reverse, usually after it's been sitting awhile. I'm gonna have my guy put it up on a lift and we'll take a look to see if something is binding or whatever.

[Sadistic]

How does your transmission fluid look? Is it burnt or brand new? I really don't think that would cause a clunk, but you never know. If it is, it's a cheap fix. The other suggestion was going to be the mounts.

[DobieG]

Hi.

This seems to be very common with Lexus/Toyota.

Here a couple of links to previously discussed topics:

http://us.lexusownersclub.com/forums/index...topic=16235&hl=

http://us.lexusownersclub.com/forums/index...topic=11283&hl=

Basically, letting the car warm up and allowing the RPMs to drop make a significant difference in shift feel from park to drive/reverse.

Let us know how it turns out.

[SponsorMy95SC4]

Guess I'll just change the fluid and live with it, hell I still have a few months of warranty left!

[rich21]

i bought my sc with 60k on it. now i have 135k. i never changed the tranny fluid. i know i know. i heard it enough so no need to say anything. would it be bad to change the fluid now?

[Sadistic]

i bought my sc with 60k on it. now i have 135k. i never changed the tranny fluid. i know i know. i heard it enough so no need to say anything.  would it be bad to change the fluid now?

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No, I don't think it would be bad to change the fluid.. Actually, I would suggest that you do. I would change the fluid, and the filter. I think you would benefit from that even if it doesn't fix your "thump" noise that you're having. I'm sure it would help firm up your shifts quite a bit, and probably just clean up the general "sloppy performance" that transmissions usually end up developing after the fluid becomes so used.

[rich21]

i bought my sc with 60k on it. now i have 135k. i never changed the tranny fluid. i know i know. i heard it enough so no need to say anything.  would it be bad to change the fluid now?

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No, I don't think it would be bad to change the fluid.. Actually, I would suggest that you do. I would change the fluid, and the filter. I think you would benefit from that even if it doesn't fix your "thump" noise that you're having. I'm sure it would help firm up your shifts quite a bit, and probably just clean up the general "sloppy performance" that transmissions usually end up developing after the fluid becomes so used.

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great thanks for the reply

[ricfla]

I had the same problem with my 92 SC400 and it was the drive shafts cusing the thump. It seems that Toyota saved a lot of money by not using U-joints to mate these guys to the transmission and differential. They used fiber bushings instead. Now there's a smart design for you. After a thousand dollars the noise went away. You may want to have them checked for wear and play. Mine were about to fall out. Also they replace one of the shaft mounts as well. I just love the dealer! They slay my wallet.

[lexus082]

I had the same problem with my 92 SC400 and it was the drive shafts cusing the thump. It seems that Toyota saved a lot of money by not using U-joints to mate these guys to the transmission and differential. They used fiber bushings instead. Now there's a smart design for you. After a thousand dollars the noise went away. You may want to have them checked for wear and play. Mine were about to fall out. Also they replace one of the shaft mounts as well. I just love the dealer! They slay my wallet.

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So what all did you have to replace?... the drive shaft and bushings and a shaft mount? Thanks.

[smcmrk]

I had the same problem with my 92 SC400 and it was the drive shafts cusing the thump. It seems that Toyota saved a lot of money by not using U-joints to mate these guys to the transmission and differential. They used fiber bushings instead. Now there's a smart design for you. After a thousand dollars the noise went away. You may want to have them checked for wear and play. Mine were about to fall out. Also they replace one of the shaft mounts as well. I just love the dealer! They slay my wallet.

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So what all did you have to replace?... the drive shaft and bushings and a shaft mount? Thanks.

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I have the same issue. From parl to reverse thump. I always sit and let the car warm up so the rpms drop. Then it is fine. I am going to have the tranny fluid changed this weekend along with a tuneup at the dreaded dealer.

[JIBBBY]

This thump you are hearing when shifting is most likely worn u-joints on your drive shaft, I have seen this on sc's with high miles. You will need to remove the drive shaft which is four nuts and bolts on each end, then once the drive shaft is removed you will notice a little play on the both ends which is not suppose to happen. Find a driveshaft shop in your area and have them replace the joints on each end of the driveshaft and then have them balance it. Bet you that clunk noise goes away. Should not cost more then $200. Good luck

[APACHE31405]

Just changed my tranny mount today and boy what a difference. i had the thump in mine, that loud humming noise coming from under the console and the feeling of going over railroad tracks at or between 30-40 mph. solved all of those problems. it has 140000 miles so it was do and the job was easy. really straight forward. i have the old transmission mount if you want to see it. change that part before you change the fluid and see if that helps.

[JIBBBY]

Could be the tranny or engine mounts that is true. Those should last up to 150,000 miles and should be checked or changed out.