[TypeC]

I just finished installing a new Wavetrac LSD (complete pumpkin swap) on my 6MT and have the following:

• Strong vibration from 20-35mph regardless of gear
• No clunking
• Update - The center bearing was spun around 180 deg during the install, causing the vibration. I spun it back to the right orientation and the vibration is gone

The car only has 30k on it and was dead silent and smooth before the swap. I bought the service manual and it suggests that a vibration at 25-30mph could be the front centering sleeve (inside flex-disc), U-joint, or flex-disc.

I don't know how it could be the u-joint, as it isn't binding and wasn't likely damaged (hung with wire).

We uninstalled the drive shaft tonight, inspected, lubed flex-disc/sleeve and re-installed and still have the same vibration. I might replace the sleeve

I'm out of ideas here. Any insight is appreciated.

Thanks,

-C

[TypeC]

Flex disc and centering sleeve are #1 and #2 above respectively.

[TypeC]

Flex disc (giubo) looks normal. I bends some when I tighten it. Thoughts on this piece?

I'm thinking of ordering the flex disc and centering sleeve tomorrow.

[tscdennab]

How did they handle the 50mm driveshaft nut that connects it to the rear diff ? Did they use a thin wrench to remove it, or did they force it somehow ?

[TypeC]

Originally Posted by tscdennab

How did they handle the 50mm driveshaft nut that connects it to the rear diff ? Did they use a thin wrench to remove it, or did they force it somehow ?

I used the AR tool. I did all the work myself.

[TypeC]

I replaced the centering sleeve and still have the same vibration from ~20-30mph.

I'm really out of ideas here and need some advice.

Thanks,

[TypeC]

Page from service manual.

[Joshboody]

I remember reading where someone installed prop shaft wrong side up (u joint). But his vibrations continued past a certain speed. I think.

[JBax]

my only advice would be to replace everything on that list one by one (starting with the least expensive part) until the problem is solved...might be the only way to get it resolved unless you want to take it to somebody and let them inspect it ?

[TypeC]

I pre-loaded the carrier bearing on the driveshaft 2-3mm then tried full-forward today with no luck.
I'm going to swap the stock diff back in tomorrow to rule-out the aftermarket gear.

[Mike@N54Tuning.com]

Did wavetrac do the assembly? Have you emailed them?

Mike

[TypeC]

Originally Posted by Mike@N54Tuning.com

Did wavetrac do the assembly? Have you emailed them?

Mike

This is a complete assembly from HPA. They haven't heard of this issue before.

I'm really amazed that with all the people who've done LSD swaps, that no one has had this issue. That makes me think it isn't something with the driveshaft, as this would be common.

[domrep]

If i recall, dzenno had a simliar issue and he found out it was damaged half shafts. After his LSD install, the vibartions were more pronounced especially in 6mt cars. For 6AT swaps they have the torque converter which muffles tons of noise. It seems you did your LSD install right, you might want to look at your shafts.

[TypeC]

Originally Posted by domrep

If i recall, dzenno had a simliar issue and he found out it was damaged half shafts. After his LSD install, the vibartions were more pronounced especially in 6mt cars. For 6AT swaps they have the torque converter which muffles tons of noise. It seems you did your LSD install right, you might want to look at your shafts.

I read that thread, however his vibration wasn't isolated to a speed and he had clunking. My car was dead silent before this, so it isn't likely the shafts.

[TypeC]

Update - I swapped the stock pumpkin back in and have the same vibration at 20mph.

At this point, it's either A driveshaft component (shaft, support bearing, U-joint), or guibo.

I don't know a good next step. The guibo (shown above), looks good. The service manual says to only turn the nuts not the bolts, which I didn't do correctly, but there is plenty of slack so I don't see how that would cause an imbalance.

Thoughts?

[TypeC]

Below are pics of the center bearing and u-joint from tonight.

[O-cha]

Dude.... you put the center bearing in upside down....

[O-cha]

New favorite image, which applies here plenty. This is on lamforder boxes (they are a division of ZF, they make the guibos)




Also take a few pictures of the guibo, I bet you put that in wrong too....

[TypeC]

Originally Posted by O-cha

Dude.... you put the center bearing in upside down....

"Dude", I never removed the center bearing. It is installed as it was from BMW. I removed the driveshaft as one complete piece and haven't touched it beyond that.

Originally Posted by O-cha

Also take a few pictures of the guibo, I bet you put that in wrong too....

The guibo is shown in several pictures above. It is actually symmetrical, and is installed per FSM with arrows pointing to flanges (there are metal bumps in it that seat into corresponding holes in the transmission output flange).
How about seeking to understand and to help before jumping to criticize.

[Bakeme521]

In my old e36 I got a bad vibration and it was because I had a bent u-joint in my driveshaft. Not saying thats what it is but it sounds like its something unbalanced along the driveshaft.

[Dr.phuOnger?]

dood.. i have the same issue... mine vibrates around 15-20mph also and then it disappears....

let me know what you find!

because i rarely drive the car it doesn't bother me that much but i would definitely like to fix it as well...

I have a quaife and I swapped it from another 335 e92. the person who installed the DIF over torqued the 50mm nut so when we used the AR tool it bent the tool.... so we just swapped the dif with the driveshaft completely from one car to another.

[marconi118]

Originally Posted by TypeC

"Dude", I never removed the center bearing. It is installed as it was from BMW. I removed the driveshaft as one complete piece and haven't touched it beyond that.



The guibo is shown in several pictures above. It is actually symmetrical, and is installed per FSM with arrows pointing to flanges (there are metal bumps in it that seat into corresponding holes in the transmission output flange).
How about seeking to understand and to help before jumping to criticize.

He Is correct you put the center bearing 180° wrong.

Rotate it 180° and bolt it again to the car. Now the center of the shaft is 30mm lower than the gearbox, the whole shaft makes a sort of V
This flexes the guibo.... and vibrations at low speed high torque acceleration

Had the same problem... was difficult to find out because it was only 10mm in my car (M3 center bearing + shaft on 335i to mount M3 LSD) but solved it by using the 1M bearing.

Notice that the 2 fixing tabs are NOT CENTERED in the bearing support, so it matters the sense you bolt it to the car