Zf whining sound?!?

[Blacks52325is]

Just getting the car all finished up and getting the first miles on it. Unfortunately, I’m noticing some interesting whine noises coming from the transmission area. When in neutral and sitting still I don’t have any noise, in gear sitting still I don’t have any noise, but once I start going and let off throttle and coast while still in gear is when I get my whining noises Does anyone on here have experience with this? I am currently running a zf 5 speed with a dkm organic twin disk. Turbo s52. I bought the trans used form a guy, clutch is brand new only a couple laps around the block. New throw out and pilot bearing (pilot bearing provided by dkm didn’t seem very tight inside crank shaft I barley tapped it and it went in) 1994 325is s52 6262, ZF 5 dkm twin disk.
Edit: here’s a link to the video for sound.

https://youtube.com/shorts/CokabeDJpQQ?si=Ey-iBP6y0rSL4b21

I AM GOING TO LEARN HOW TO POST VIDEO SO YOU CAN HEAR…. Let me research and tech myself how. Thank you all!

[hakentt]

I bought the trans used form a guy,l!

that is the problem with buying used transmissions, you have to take seller's word that is good. It was probably ran low on oil and gears got worn a bit

[Sio2crew]

Totally normal for 1st and 2nd to whine on de acceleration in gear, when you have a single mass fly wheel. My turbo s52 / zf320/ twindisc clutchmasters 850 sounded the same way . (SOUNDS Like strait cut gears.) I run a 6 speed 420g now.

The only problem I had was the horrendous design seems legit tried to use to adapt a zf5 speed to their single piece driveshaft. ( not what you asked , just what happened to me. ) I thought I broke the input shaft bearing at first. Zf 5 speed input shaft has a lot of radial play. A few mm more vs. a 420g 6 speed input shaft, when you grab them by hand. Apears to be normal tho. All 3 of my zf320's have that play. They all worked fine before I pulled them out of personal cars. One has less than 30,000 miles, same play, same noise with a single mass flywheel. No 1st and 2nd gear noise when run with a factory dual mass / stock clutch.


The bolts seems legit supplies are much smaller than the three holes in the rear triangle on a 96mm guibo flange trans. They were TIGHT. Who knows the torque value, no instructions, no name hardware with no markings. (Seems legit ghosted me when I talked to them on the phone multiple times, and E mailed for help/ info. I Never asked for a refund, ) Destroyed itself in a few hundred miles. Caused lots of vibrations as you could imagine.

As long as your zf was not abused by another turbo build before you got it, it's probably fine. You could swap the fluid for good measure, inspect the old stuff for debris if your really worried, or if its different symptoms than I described. The fluid only fills the bottom few inches of the case. As far as I'm aware, Most gears are above that level and splash lubricated only. Syncros in the zf are pretty strong. From what I have seen , when they die from high power they tend to loose 3rd. (Wants to pop out of third is a symptom) I know the syncros in the 420g are supposed to be more delicate.

Only other thing I can think of, at first I used condor white engine/trans mounts. When I swapped out to the 6 speed, I kept the condor engine mounts, and went to rubber trans mounts. (Ireland h.d. ones) that change seemed to help NVH. Makes sense as your trans mounts are basically bolted to the underside of your seat rails. Rtd Shifter feels just as good driving fast. I found no down sides to the softer trans mounts vs. Condor. ( tried bolth ways with a factory driveshaft. )

[pbonsalb]

Yes, trans mounts must be no more than about 80 in shore rating. I tried a few “upgrades” that were miserable in street driving for the ZF320. Bad driveshaft ujoint usually causes clunking. Bad center support bearing could cause vibration—worth researching the symptoms.

High powered turbo S52 will eventually kill a ZF320. I killed two. But if you stay under maybe 450 lbs rwtq that will help. 320 NM is the torque rating, which is about 240 ft lbs. ZF is conservative, but any turbo S52 is way way over the limit. Over the limit of a 420G or GS-53 as well but BMW did put the GS6-53 behind the S63 in the F10 M5 that made more than 530 NM stock so the rating is definitely very conservative.