[canadiannova]

well first off, i am baffled!! i have only done a few diffs in the past but have never run into any problems...till now. i have an 8.5 10 bolt that i am installing a motive spool, aam 3.73 gears, moser c clip elims, and moser axles. my contact pattern is about half way up the tooth but way out on the outside of the tooth. i would have thought that moving the pinion in and the carrier to the drivers side should fix this but no!! i have a ton of shim behind the pinion bearing and nothing on the drivers side of the carrier...i just cant get the pattern to move toward the center of the ring gear ...any thoughts? i must be missing something simple, cause this just isnt working!!

 

[chevyIIheavy]

try this mate www.jegs.com/installationinstructions/500/555/555-60029.pdf

 

[canadiannova]

I have looked at a ton of those pattern charts and they all tell me to add pinion shims, but i cant because i already have zero backlash and no more shims to remove from the left side of the carrier!!

 

[The Big Al]

Can you take some pics?



With no shims on one side of the carrier?:no:

Al

What do you call half way up?

 

[canadiannova]

hey al, i forgot to take pics, i will on monday...i just dont get it...i even double checked part numbers just to be sure i had all the right parts, like i said, im baffled!!

 

[71SS454]

I'd triple check the part numbers. If you have no shim at ll on the passengerside of the carrier, and alot of pinion shims in there, the assumption is that you have a 3.73 gear designed for a 4 series carrier bolted to a 3 series carrier (or spool). The ring gear spacer that can be used to make this work is about the same thickness as the factory passenger side shim, so that's what I think the problem is.

We did that to bugger together a rear end on a friends car once to get it home. We had a set of 3.42 gears, and only the stock carrier for 2.41's. (this was a road side repair, so nothing was properly checked or set, just thrown together). We installed everything, but put both shims on the driverside to move the ring gear close enough to the pinion. It actually worked pretty good except getting the c-clip in the driverside was a PITA, and the passenger side axle hung out a bit. After about 30 miles, boy did she start howling.

 

[canadiannova]

it is the drivers side of the carrier that has no shim....i cant get the ring gear far enough AWAY from the pinion...

 

[71SS454]

Ok, so then you have it the other way around, a gear designed for a 3 series carrier on a 4 series carrier putting the ring gear too close to the pinion.

 

[The Big Al]

Ok, so then you have it the other way around, a gear designed for a 3 series carrier on a 4 series carrier putting the ring gear too close to the pinion.

i thought the same.

but there is only one for a 8.5

Al

 

[canadiannova]

yeah, there is only one spool available...i still didnt get pics, i am going to take another stab at it tomorrow...would be a lot easier if i had a pinion depth guage rather than the trial and error method i am using now (mostly error) this is kinda embarassing as i am a licensed tech...i cant believe this is screwin me over this bad!!! i will have an update tomorrow...thanks guys.

 

[71SS454]

see, that's what I'm thinking. Since a spool is a race only part, it'll be designed for steep gears and I'm willingb ot bet it has the dimentions of a 4 series carrier. If your 3.73 ring and pinion is the standard 3.73 set, it's designed for a 3 series carrier, thus making your ring gear too thick for your set up. The do make a set of 3.73's designed for a 4 series carrier and I bet that's what you need for your rear. The set with the thinner ring gear.

 

[DERYL ATANASU]

rear end

it sounds like you have too much shim behind the pinion. a good starting point is to use the shims you took out.

 

[The Big Al]

You should not have any shims in the pinion to start.

And the stock carrier shims in place to take a reading or pattern check.

It should not take a lot of shims on the pinion.

This almost sounds like wrong parts.

I don't understand your scenario with your terminology.

"my contact pattern is about half way up the tooth but way out on the outside of the tooth"
(witch way is up & out?)

Also are you looking at the drive side of the tooth, not the coast side?

 

[canadiannova]

ok...pattern is on the heel of the tooth and will not move regardless of what shims i use. i am sending the gears back and getting a different set...there is no way these are correct...the part numbers are right but there is obviously something wrong. i will give an update early next week as i will not have the gears until saturday.

 

[canadiannova]

Ok, i got a different set of gears and guess what? within one hour it was set up perfectly!!! obviously a faulty set of gears. got the whole think set up, housing is painter, ta girdle installed...ready to go, now if the car ever gets out of the body shop i can install it!! thanks for the input guys, i really appreciate the help.