Transmission Noise??

[Speed04]

This is probably pretty obvoius for most of y'all, but I just wanted to see if there was anything I could do myself.

Recently, I've started to hear a knocking noise from under the car. It sounds like it's coming from the transmission, and looking around under the car, nothing is loose. I haven't had any problems with the car, just this knocking noise which usually happens when I brake or go over bumps. Every now and then, I can hear it when I let off the gas after running it up to 4500+ rpms. I was wondering if there's anything I should check or just suck it up and take it to a shop and see if I have to drop a grand+ on transmission work. Thanks

[TheRealWave]

Maybe transmition mount. does the shifter jump up any when it happens?

[Speed04]

No, it doesn't ever jump. I want to think it's something like just mounts or something along those lines, cause I don't notice any problems with performance, just the vibrating/knocking noise. Could you give me a quick walk-though on how to check the mounts? I'm very inexperienced when it comes to transmissions and some internal engine stuff. Thanks for the help.

[RallyRed 98]

auto or manual trans?

i know for the M5 you can crawl under there and visually inspect the mount for cracks, shearing, etc. you should have a black crossmember just towards the front of the trans; the mount is the rubber deal between the trans and the crossmember. i just replaced my stock mount with a polyurethane one and to my surprise, there was only one bolt hold the stock mount in! :mad: should have been two, some jackass forgot to put the old one back in or it backed itself out. i really hope it isn't the latter.

your problem really sounds like the mount though. 2 hours work if you take a 1 hour break :D

[Jerriko]

Since you also hear the noise when you back off of the gas, I would check your universal joints, especially the first one that connects the york to the driveshaft. When they go bad, you will hear a knocking noise when you accelerate or decelerate or shift from forward to reverse or vice versa. Sometimes a vibration can be felt/heard while at cruise.

[Distephano]

<blockquote>quote:</font><hr>Originally posted by RallyRed 98:
your problem really sounds like the mount though. 2 hours work if you take a 1 hour break :D <hr></blockquote>

:D Try like 30 mintues... Changing the tranny mount is a Quick job [img]smile.gif[/img]

[DrFix2Fly]

If it's an auto, you may have a cracked flexplate or even a broken torque converter hub. It the ticking is closer to the engine, you probably have one of those problems. It happened to me.

[Speed04]

After being home for a few days with a garage and tools, I went ahead and replaced the tranny mount. I figured if that wasn't it, it wouldn't hurt anything replacing it. Well, that's definatley not what is causing the noise, cause it's still doing it. I really think it's the drive-shaft (or the u-joints). Is there any specific way to check this? And if it is, would it be smarter to just get the u-joint fixed or just replace the drive shaft with a one-piece. Chances are, I'd have to get this done somewhere, cause I don't have enough experience on cars. Thanks for the help.