I Just swapped out my 3.21s for 4.11 with a complete kit from Nitro Gears from their distributer Just Differentials.

2500 miles later the ring has sheared off of the rear carrier leaving me with a broken ring, damaged carrier, bearings etc.

I called Just Differentials and they are claiming installer error. They are saying the bolts must not have been torqued or used with loctite.

My mechanic said that the bolts failed because they are too short and the shank does not match up to the carrier holes and that he torqued them and used loctite.

The carrier has 1/2 bolt holes and the nitro gear ring is for 7/16. Upon further discussion with Just Diff. they claim its "OK to use 7/16th bolts in the 1/2 inch holes."

I asked them why that most of their other ring gears have threads for both on the same gear and so does the competition. Just Diff. replied that it depends on the size of the gear and their larger gears need it but the 4.11s do not.

I am now $900 in the hole PLUS labor (not including the $2400 the gear swap cost me the first time.

Anyone else have this problem and can provide me a little assistance?

Thanks for any help.

 

I don't have any honest reply but I cringe for you. I'm sorry this happened to you.

 

If your mechanic knew the bolts were too short,, WHY THE HELL DID HE USE THEM!!!!!!!! Sounds like he just admitted the instal failure was his!!!

 

He used them because they were supplied by nitro. He thinks they may have been too short but they torqued up. It's just a possible hypothesis of why they failed.

 

I'm with you. Sounds like the guy knew stuff was wrong and installed anyways. I would be looking to him for answers. Also $2400 is pretty high too. Got to go with what's around I guess. It's bout the sane for me in my area. That's why I'll be driving 3 hours to dallas or Houston to get it done for round $1000 parts and labor

 

You shouldn't be out any money as one of them is responsible. I lean more towards an install error

 

That's purely installer error.

Have him refund you and take it to someone that actually knows what they're doing.

 

I imagine the 7/16" bolt allowed the ring gear to move around since the shoulder was smaller than the hole in the gear. This would allow a lot of shear forces against the bolt. It sucks to have issues like this!

 

What does NITRO say? It's their gear set. Just Differentials is the middle man.

Also, hopefully you were working with a reputable installer?

 

The short bolts where the cause of your failure. The bolts being too short does not spread the load far enough over the bolt to make them effective. As far as who is responsible for the failure, you are. After your mechanic told you the bolts where to short you should of stopped him until it was resolved. Second buy gears from a quality manufacturer who stands behind there product.


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