[dono1]

How many teeth are on the crown wheel and pinion on a 3.7 sierra diff? I have a set of 3.7's and 3.9's but I'm not sure which is which (they are all in a parts bin I got with my old car).

Thanks in advance.
Donny.

[tanshi]

http://auszookers.com/forum/viewtopic.p ... &view=next

[Reubs]

Count the teeth and divide the numbers to determine the ratio...

[dono1]

Thanks for the help, are the pinion teeth the same in both??

[tanshi]

they are the same number but different sizes i believe

[dono1]

Great! Which one will go with the 3.7 the larger pinion or the smaller pinion??

[christover1]

In my old cars a lot of r & p were marked to show what they match to.
Not checked zook stuff

[jono165]

I would think that larger pinion should go with the crown wheel that has coarser teeth which is the 3.7:1 pair.

[Fatzook]

You shouldn't mix and match your pinion and ring gears. They are a matched pair, and are worn in together. Mismatched R&P's canbecome noisey, and even fail earlier than otherwise expected.