would appreciate advice on how this pattern looks. Motive 4.10

I know it’s pic overload but figured it can’t hurt even though some of the pictures probably look identical lol.

also is .006 backlash acceptable?

thanks

 

coast side. 2000 trans am 10bolt

 

IMO, I think your pinion shim is dead-on, but your backlash is a tad too tight, putting the drive-side contact too deep on the ring gear teeth (which would be too close to the tip of the pinion teeth where it is weaker). My bet is a backlash of 0.008 would get you there.

 

Too close to root. Lash comes with a range, but the gears may of been lapped in with something different.

 

backlash doesn't change pattern from my experience. Those will run just fine, however if i was doing it I would pull some pinion shim out and see if i could center it a little better. Try 5 thou less.

 

Agree with being too deep and too tight...shoot for tooth center and .008
After a dozen times in/out...yes, I got a little happy with the yellow marking compound

 

Much better. Lash does matter, more on certain gears than others. Hopefully I've got a clue by now, couple of builds under my belt. Always consider the orig lap style on the teeth. Keep in mind, you may not always be able to duplicate them, that's where strong experience and training help determine serviceability and if there is a way out.

Best of luck

 

Thanks for the responses.

I end up sending it like that..
It was quiet as a mouse for 250 miles. Made zero noise. Then after the first track visit and 2 runs it whines pretty bad.
don’t really understand why. I know all bearings and races were seated.
oh well, it’ll stay till it blows up lol.

something I did notice however, and am curious about…
The pattern looks kinda deep in the pics, I agree.
But when I pulled the cover after a couple hundred miles and compared the wear pattern between the 4.10 and my stock gears I noticed that this pattern meshes pretty high on the ring gear teeth. No gap at the top. Pretty big gap at the bottom.
the mesh on the factory gear is much further down with a small gap on top of teeth.

 

Basically the pattern on the teeth now look identical to the tooth circled in this picture. I am referring to the entire paint mark.
no gap at top and sizable gap at bottom.
looks like contact should actually be further down.

 

Something wasn't on all the way. Definitely too close to root.

 

This is a genuine question, I’m just trying to understand…so I can know for the future

but why does the paint mark (circled in pic) not close to the bottom of the tooth if it’s too deep?

I agree the other pics make it look like the contact is deep. But if you look at the paint transfer on other teeth there is a fairly big gap between the bottom of the paint mark and the bottom of the tooth. And the current wear on the teeth are the same.

I also notice that there is a “paint ridge” on the painted teeth that looks like it’s the bottom of the tooth but it’s actually not.
It kinda seems like the paint transfer onto the non painted teeth give a better indication of contact than the actual painted teeth do.

 

The gears will want to take after the lap in pattern from the factory. Put a clear picture up of one tooth drive and coast side. Ideal hi load scenario start closer to toe on drive side, but can't always be achieved.