///M stock LSD upgrade to 3.91

[lrz]

Hello,
I want to upgrade my stock differential to 3.91.
What parts do I need for the upgrade?
This will be enough?

https://www.ecstuning.com/b-genuine-...net&utm_term=1

[rueyme]

yes i am doing the same as well. where are you located?

[maupineda]

I think you may want to replace bearings and seals.

Racing diffs have some very attractive kits which include the clutch packs

[lrz]

Thank you very much for your answers.
Unfortunately, I'm not located in the US.

[GuidoK]

there is probably a crimp bushing between the outer inputshaftbearing and inner inputshaftbearing.
That bushing has to be replaced too, to set the correct clearance.
If not, it's (bearings on the inputshaft that is) shimmed and you need both shims and a special tool to measure the size of the shims you need.
That would look something like this:


and new seals of cours.

Mind you, this is not an easy swap. Don't attempt this if you dont have experience with differentials. To make it worse... there is no data about settings (backlash etc) and you need a very special fricton meter tool to monitor the force it takes to rotate the input shaft to set the pretention on the bearings:

[lrz]

Thanks for your great help!

[tominizer]

People a lot smarter at building cars than I am have cautioned against DIY-ing this. It will become a HUGE regret unless you have a LOT of experience or get super lucky. It's cheaper yes ..........in the beginning.

[1zpower7]

This job is for the pros....