Hey, I am looking for a solid answer on this.


Do the 3.90 and 4.10 differential have the exact same housing(pumpkin). I know they look the same but are they exactly the same?

Also, the the gear off the driveshaft(pinion gear) is that the same on ALL fc difs?


I ask because I am planning on putting a s4 lsd into a 3.90 pumpkin out of a 88 vert.


Thanks in advance for the help.

 

Anyone?

 

All NA Pumpkins are the same size(7"), where the Turbo pumpkin will always be 8" if OEM.

Now for your other question I have no answer since im not good with gearing type stuff sorry.

 

gears are normally changed as a ring and pinion, so the pinion gear is obviously different

 

Ok, thanks for the help

 

+1

the pinions have to match the ring gear, you can easily change the gear on the diff though.

and yes all NA and Turbo pumpkins are different, but other than that they're the same.