[Offset Motorwerks]

Originally Posted by stephenf121

offset motorwerks, is there a special soft bushing that could go on the lsd to take away some thump? If so which ones and what kind would you recommend?

Mfactory makes some nice solid rubber bushings, but I personally prefer hard poly and live with the added noises

[MFactory]

Our Diff Bushings are Thermoplastic Vulcanisate, not rubber (is kind of inbetween Rubber and Poly)

Diff Thump is there with any LSD, as there must be free-play inside the LSD as the gears expand when warm. If there wasn't any free-play, the gears and housing would friction weld itself together. This is all detailed in our FAQ (in my signature)

How much you hear this "thump" though, depends on several variables (including the driver), and can be minimised by:

1) Changing to softer chassis bushings (it's not just the diff bushings that affect this)
2) Checking your Propshaft Centre Bearing for wear and most importantly pre-loading it properly (this is a common issue, but 90% of installers don't bother checking this, and most "specialists" don't even know what this means. ALWAYS check with the LSD manufacturer first if you are having issues)
3) Make sure the LSD is shimmed properly so that the back-lash on the ring & pinion is within oem tolerances (most installers do not have the proper c-clips/shims to do this, so always make sure to check with them first. If not, you MUST buy a shim kit from the LSD manufacturer, as BMW do not sell these)

[Joey911]

Originally Posted by MFactory

Diff Thump is there with any LSD, as there must be free-play inside the LSD as the gears expand when warm. If there wasn't any free-play, the gears and housing would friction weld itself together. This is all detailed in our FAQ (in my signature)

How much you hear this "thump" though, depends on several variables (including the driver), and can be minimised by:

1) Changing to softer chassis bushings (it's not just the diff bushings that affect this)
2) Checking your Propshaft Centre Bearing for wear and most importantly pre-loading it properly (this is a common issue, but 90% of installers don't bother checking this)
3) Make sure the LSD is shimmed properly so that the back-lash on the ring & pinion is within oem tolerances (most installers do not have the proper c-clips/shims to do this, so always make sure to check with them first. If not, you MUST buy a shim kit from the LSD manufacturer, as BMW do not sell these)

I have differential work done by Diffsonline, and install with a BMW Indy.

So who's job is it to do the preloading thing that matters?

[MFactory]

It would be the job of the installer i.e your BMW Indy

[Joey911]

Originally Posted by MFactory

It would be the job of the installer i.e your BMW Indy

They did mention they did not drop the whole driveshaft...

[MFactory]

It's a 2pc propshaft, so only the rear part needs to be removed, and this is where the problem lays, as it is the centre support bearing that causes the issue.

[Joey911]

Originally Posted by MFactory

It's a 2pc propshaft, so only the rear part needs to be removed, and this is where the problem lays, as it is the centre support bearing that causes the issue.

They swore to be they did preloading the bearing.. I have no idea where to bring my car to. Do you think technician will do a better job following the right procedures?

[Offset Motorwerks]

Originally Posted by MFactory

Our Diff Bushings are Thermoplastic Vulcanisate, not rubber (is kind of inbetween Rubber and Poly)

Sorry, my mistake!

Originally Posted by MFactory

Make sure the LSD is shimmed properly so that the back-lash on the ring & pinion is within oem tolerances (most installers do not have the proper c-clips/shims to do this, so always make sure to check with them first. If not, you MUST buy a shim kit from the LSD manufacturer, as BMW do not sell these)

This is crucial!! Also why we let Mfactory assemble all of the differentials we sell/install. It helps that they are 5 minutes away

Originally Posted by MFactory

It's a 2pc propshaft, so only the rear part needs to be removed, and this is where the problem lays, as it is the centre support bearing that causes the issue.

Agreed about the preload, but I have found that we don't have to remove the driveshaft at all when installing a differential

[Joey911]

Update to Original thread guys