Transmission noise into the cabin after DSSR install

[finnmole]

It was a long day to replace the shifter bushings to repair a sloppy shifter in my E30.
I was worried about the vibration dampener but it turned out that in an 88 it just comes off easy...basically just loosened the centre support and dropped the drive shaft a little and it just came off (without the 60 deg turn mentioned in the Bentley)
To get the output shaft seal out, I had to use a pick and just scrape it off as it was like fused in there....appears not to leak anymore.

I installed a Garagistic DSSR and delrin bushings in the shifter arm, front and inside the rear carrier. Changed the selector rod joint to the late model non-offset version.
The shifting is so solid now; issue is that now I hear the transmission gears turning as I drive...it's like someone opened up the floor boards above the transmission...sounds like a race car at higher speeds.
I want to hear the notes from the engine, not the tranny gears turning.

Is this something anyone else experienced?
I'm wondering now if I should of used rubber bushings...

[D.Martijn]

I also have some transmission noise by using condor speedshop delrin bushing on my iX Touring
On my uncles iX, I used (I think) IE poly bushing at the transmission side when installing his short shifter and the noise is definitely less noticeable.

[finnmole]

I think I will change the carrier bushing to rubber as that's the easiest to access, to see if it makes a difference.
Have to wait for parts though...I bought some sound deadening tape for now, will wrap the DSSR with it.

[finnmole]

So I wrapped the DSSR with the sound deadening tape; appears to have made a difference, at least seems tolerable now.
The shifting is so precise :) I would recommend going with a DSSR...perhaps use rubber bushings if it's not a track car.

[lukeADE335i]

Have often wondered whether the delrin shifter bushes would make the gearbox noise unbearable - good to hear your experiences.

I ran poly gearbox mounts for a while and found the same problem, so went back to rubber mounts with enforcer cups and it was all good.

[AndrewBird]

The noise is likely being transferred into the body through the rear shift carrier mount. Keep that rubber and you should be fine. Even with a brass bushing in the transmission side, there is no added noise.

[finnmole]

Thanks, I will change that rear carrier bushing...I thought I could do that with the drive shaft in place...no can do.
It will have to wait till the big job (and hopefully last big job) of replacing the sub frame bushings and rear trailing arm bushings...and yes I bought rubber for those :)

[bmwman91]

Yeah, sounds like a result of a solid rear carrier mount. I have the DSSR (and second the recommendation) with poly bushings for the selector rod, BUT I went with the Turner rear carrier mount that has a polyurethane bushing. I can't say that I noticed an increase in sound. Granted, I have the whole floorpan covered in Damplifier sound deadening and I installed it during a 7 month period when the engine was out of it so I didn't exactly listen to it the same weekend, but again I don't think there was an increase in noise.

[finnmole]

So I finally finished the job of replacing the subframe bushings, trailing arm bushings...changed out the transmission mounts (though they looked fine) and the rear carrier bushing to the BMW stock rubber one.
Some brake line work as well...the car sounds normal again!
The ride is so stable with the new bushings, feels so great and the shifting feels perfect with the rubber carrier bushing.

I have to admit though to my embarrassment that I had mistakenly put in 10W-30 synthetic oil just before the DSSR install...oil started leaking pretty bad.
I since drained the oil and put in conventional 20W-50 (a little thick in the winter I know) but now no more leaks and I'm now wondering if the increased noise was from the thinner oil.
It was definitely transmission noise though...oh well it's success in the end.

[NYCDelphin]

@ finnmole: thanks so much for sharing this. I have an 88 325e seta and I am currently looking into the Garagistic DSSR.

Can you post your parts list (after you fixed the sound issue )
I just wanna make 1 purchase and then start the job.

again, Thanks ! and its weird how I came here looking for info on DSSR and 325e and your post is exactly what I needed. :)

[finnmole]

HI, sorry I missed your post...I'm guessing you're already done this job.
I purchased the DSSR and selector rod joint from Garagistic.

https://www.garagistic.com/products/e30-325i-dssr-187mm

https://www.garagistic.com/products/shift-selector-joint-25117503525-bmw-dssr

You need the newer style selector rod joint with a DSSR (my old one was the off-set one) you also need to leave out the vibration damper (if your car came with one) as the DSSR would rub on the damper.
I also ordered the parts 2,3 and 6 from the diagram found in this site, I also ordered part 7 in case the old one was ripped...it was fine.

https://www.rtsauto.com/how-to-fix-a-sloppy-and-worn-e30-shifter-and-make-it-tighter-then-original-video-included/

Ordered those parts from ECS Tuning...best to look up the actual part numbers from the Online BMW parts Catalogue for your vehicle to find the correct parts
Also make sure thee 187mm is the correct one for your car...mine is an 88 325 iS

The biggest PITA was getting the parts 2,3 replaced, I dropped the tranny a bit make access easier.