Change Gears And Then Clunk!

[Wilfred]

Hello

My friend noticed that when i changed gears from Park through the gears to R N and D, there was a noticeable clunk. Its a 15yo LS400.

Anyone else had this happen to them? Anyone hazzard of guessing what that could be and should it be attended to. The actual gear box is fine i think its still running very smoothly and you can't notice the gear shifts in Drive at all.

Thanks in advance

[RFeldes]

Hi Wilfred,

Would be indicative of Universal Joint, and I'm not sure of the Lexus drive train or transmission mounts or motor mounts, none serious. I'm sure someone here will have a better grip on it as I have not experienced it. Regards

[silvermate]

i had the same problem a couple years ago, thought it was my tranny so i took it in.

it was actually a 15 dollar differential bushing...........the bushing was worn complely down so when the rear end torqued (like when you put it in gear or reverse) it would hit metal to metal, causing the clunk or popping sound

needless to say when i found that it was a 15 dollar bushing and 30 dollars labor i was very relieved.

hope thats the case for you as well.

[Wilfred]

But then how much is it for labour silvermate? I'll let my mechanic know that the diff bushing may need attention. What happens if i left it?

[ArmyofOne]

But then how much is it for labour silvermate? I'll let my mechanic know that the diff bushing may need attention. What happens if i left it?

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if you leave it, tehre si a good chance your driveshaft may fall out, if i am reading this thread cirrectly.

have you checked transmission mounts?

[Lexus_Luxembourg]

But then how much is it for labour silvermate? I'll let my mechanic know that the diff bushing may need attention. What happens if i left it?

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This is a call for disaster if it's really an U-joint. Those do let go under changing loads which means either when applying heavy load and changing gears or when backing up a hill. Just figure out what a 5 feet long iron tube, weighing about 30 pounds and flying around under your car at 3000 rotations per minute will do. I have seen cars that jumped up when the joint let loose, being propelled in the air for dozens of yards.

Even if it's "only" a trans or motor mount it will cost you more the later you have it changed. Remember that once gone the other mounts, which are already old, will have to carry twice the load they were designed for. At the end something will give.

[silvermate]

well, the bushing thing is just a suggestion.......i mean it happened to me, same symptons same solution...it could be something else, like others have mentioned...... its just really hard to diagnose over the internet, all we can really do is offer exerienced oppinions from the info given. <_<

lets hope that it is the bushing

like i said in my above post my Mech. charged me 30 bucks to do it........but he's my guy so he didn't charge me much, but it shouldn't be too expensive to change the bushing out.

good luck man.