All you Diff experts out there!

[e30_3I8I]

So im getting my e30 lsd rebuilt and the guy tells me that my pinion gear's shaft is all scratched up and so i need new gears. Im heading to the junkyard now to see what I can find. What bmw models differentials have gears that can bolt up directly to an e30 medium case lsd unit?

[Todd Black 88]

What ratio?

[e30_3I8I]

What ratio?

I was looking for any ratio between 3.25 - 3.73. I actually ended up picking up a 3.91 from a e36 328i, since I didn't have any luck finding anything else...they are both medium case (188mm). Any idea if the internal gears can just swap out into my e30 lsd unit?

[dsphil]

The easiest route is find a used lsd with good gears and replace the clutch disc. Or get one that is already rebuilt.

[mr2peak]

^ Fully rebuilding one is the correct way to do it.

Not sure if they will fit. Just make sure you use both the pinion and ring gears from the donor even if it's the same ratio as your original diff.

[e30_3I8I]

The easiest route is find a used lsd with good gears and replace the clutch disc. Or get one that is already rebuilt.

I agree with that being the easiest, I am in the process of getting mine rebuilt, just ran into an unexpected problem with the shaft of the pinon being scratched up which was caused when the lsd gave out on the freeway on my way to work one morning. Also, Why replace the clutch disc???

^ Fully rebuilding one is the correct way to do it.

Not sure if they will fit. Just make sure you use both the pinion and ring gears from the donor even if it's the same ratio as your original diff.

Yea, the guy I took it to specializes in all differentials and he also recommended using both pinion and ring gears, thats why i figured why not just change the gears out to a different ratio. Unfortunately I couldn't even find any of the ratios I was actually looking for...DAMN you junkyard people! lol

[dsphil]

I agree with that being the easiest, I am in the process of getting mine rebuilt, just ran into an unexpected problem with the shaft of the pinon being scratched up which was caused when the lsd gave out on the freeway on my way to work one morning. Also, Why replace the clutch disc???



Yea, the guy I took it to specializes in all differentials and he also recommended using both pinion and ring gears, thats why i figured why not just change the gears out to a different ratio. Unfortunately I couldn't even find any of the ratios I was actually looking for...DAMN you junkyard people! lol

What do you mean by "the lsd gave out on the freeway"? do you mean the bearings went bad? I dont' think the scratches on the shaft will make it a bad diff if the gears, seals, torque, and backlash is still good. Post pic of the scratches.

[mr2peak]

I don't think all ratios are swappable, but you should be able to split an open diff and use those as well I believe. Gives you much more choices, nobody buys open diffs so they're cheap.