need measurements for Motive 3.73 gears!!
 

does anyone know the measurements i need? i just bought the 3.73 Motive gears for my 98 bird but they didnt come with instructions or measurements. can someone help me?

Not sure what you mean by measurements. If you mean what spacing to set them up with, you will have to check that yourself. Every rear is slightly different because no two rear end housings are exactly alike.

If you have never installed gears before I would advise you to either take them to a professional, or have someone with plenty of experience there to assist you.

If you don't get them setup just right, then you just ruined a brand new set of gears.

- Justin

::edit:: After viewing that other post you made (which was unnecessary thanks to this one), I have to ask - are these gears used?

If so, you need to get the measurements from the previous owner.

ditto, have a pro do it. if its not done right you will hear whine and the rear won't last long.

It is at a shop (JS Performance). That's why I'm thinking it's a set of used gears, and Josh needs the measurements of the shims and whatnot that they were installed with before.

- Justin

na they gears are new i got them from thunderracing.com. it looks like they forgot to put the instructions in the box. josh said he needs the backlash settings?

Hmm....I was always under the impression that there were no set measurements for installing new gears. :shrug: I guess this is why I have someone else install gears....

- Justin

Thats what I thought too, in fact one of my rears had to be pulled twice because the settings caused a whine. Each set up is different.

I can't remember exactly, I think you have to set the depth with a dial indicator, adjustments are made via the crush sleeve, Then you use the marking compound to check how the gears mesh and shim the diff. right/left to get the right contact patch. Or something somewhat like that??

I know the Motive are set to factory specs. Some company want the specs tighter/looser, but Motion was set to GM specs. I don't have a manual handy to check.

When Jon (BAD97SS) did mine he said they were dead on factory specs and I only have the slightest whine when coasting. Of course, that did nothing to prevent me from killing the posi unit!

well i called the place i bought the gears from and they told me that motive used 8-10k backlash. I hope they are right or they will be sending me a new set of gears. :lol:

The reason i got the gears was because there was a loud whining noise coming from my rear. When i let off the gas it went away and when i gave it gas it mostly went away. But it makes a loud whining when i just barely gave it gas and i mostly hear it in the higher gears 3rd, 4th, 5th, 6th. When my local mechanic took a look at it he said i didnt have oil in my rear and he found some metal shavings. Josh from JS Performance told me my gears dont look bad and my posi is alright. After i put the new gears in and it sounds the same would you guys have any idea what it could be??

.008 to .010 is a little loose for high powered cars but that might be what they call for -- the reason is - the ring gear the way its made -- i dont do street diffs so all i can tell you is we check it in 8 places around the gear like a pizza -- this way we can average the distance equally as gear goes around ina circle - we try to get lets just say .006 but if the gear is made funny the short side will end up at .001 and the wide side could be .009 -- don't know if you get what i mean -- some gear company's are a lot better than others and its only after the bearings and threads have been used you find out -- a real shop knows to heat the ring gear and chill the carrier so the two end up as flat as possible against each other, this will insure the flatest gear mesh good luck all i hear is the street gears are a hand full to keep quiet -- jz