I'm swapping in a 4th gen differential, and it has posi in it, I know to use 2 bottles of posi additive, does it have to be GM brand or will others work just as fine? is kendall a good brand of posi additive?

Also 15 tooth drive and 40 tooth driven are the correct gears for the 3.42 ratio right? I just want to be sure. I'm switching it from 2.73 to 3.42, what would the original 2.73 gears have had for speedo gears? And please don't just reply and tell me to see the sticky about 10 bolts, i have read it many times and this info is not in there.

 

okay, so i was calling some places to find out about getting these, most couldn't find anything. I found the 2 gears and the guy said that all he found was one housing for the driven gear.

I still wasn't satisfyed so i looked in my gm parts books and it says the 3.42 gears should have a gray 15 tooth drive gear, and a yellow 41 tooth driven gear, and it didn't mention the housings being different, so will my 37 tooth driven gear housing/sleeve work with the 41 tooth gear??

So now i'm going to get the gray 15 tooth drive gear, and yellow 41 tooth driven gear, with 3.42 gears, and 235 60R15 tires, does this sound right???

 

Depends on the differential. If it is an Auburn then you will need 2 bottles of additive. I'd use the Ford additive. Do not use Kendall or other after market additives. Use GM or Ford additive only. If it is a Torsen then you don't need the additive.

 

I'll know this weekend what posi it is. I have to finish painting it then i will pull the cover to change the fluid and check the gear ratio for sure. I'll get some pictures of it too.

 

so does anybody know for sure if the 41 driven gear will work in the housing that i have right now for the 37 tooth driven gear??????

 

for what i understand there is a different housing for 40+.

 

well looks like I'll be going to the junkyard this friday to look for the housing and the gear if can't find it at some transmission shops this week.