Bad experience with ring gear spacer.
Bad experience with ring gear spacer. Well I tried to swap my 2.73 rear to 3.42 this weekend. I had a set of used 3 series 3.42s from a 6-speed car and a Motive spacer. Come to find out, once the spacer is installed, there is no machined register on the carrier left for the ring gear to fit on. The thickness of the spacer takes up all but 1/16" of that register, and with the chamfer on the bottom of the ring gear there is none left to make contact with. That means the ring gear can wallow around 20-30 thousandths or so once the bolts are in before they're tightened.
Basically, the ring gear bolts are intended to center the ring gear...which I will never be convinced that they can do. Plain and simple, the bolts have the job of keeping the ring gear from spinning on the carrier. They will NEVER be able to keep that gear centered.
Now the way I figure, if I call Motive they will tell me to set it up with v-blocks and get it perfectly centered within a thousandth or so. That's bullshit. The first hard launch on relatively sticky tires will knock that gear out of center with the carrier. Once that happens, you're basically ******* your pinion depth, only by having the ring gear move out of round instead.
Moral of the story is I put the damn thing back together with the friggin 2.73s. I'll be shelling out the money for a new set of gears with the thick ring gear. That effin' spacer will be getting returned.
I just wanted to vent and warn anybody who was interested of my problem.
Basically, the ring gear bolts are intended to center the ring gear...which I will never be convinced that they can do. Plain and simple, the bolts have the job of keeping the ring gear from spinning on the carrier. They will NEVER be able to keep that gear centered.
Now the way I figure, if I call Motive they will tell me to set it up with v-blocks and get it perfectly centered within a thousandth or so. That's bullshit. The first hard launch on relatively sticky tires will knock that gear out of center with the carrier. Once that happens, you're basically ******* your pinion depth, only by having the ring gear move out of round instead.
Moral of the story is I put the damn thing back together with the friggin 2.73s. I'll be shelling out the money for a new set of gears with the thick ring gear. That effin' spacer will be getting returned.
I just wanted to vent and warn anybody who was interested of my problem.
Originally Posted by keliente
Thanks for the information, this will be helpful to others in the future, even though it was at your expense 
That's why I posted it up. I guess this is something i should have seen since I do so much research on every mod I attempt to do, especially since I give every effort to do things myself and learn as much as possible. However, I had never seen a single thread or piece of information that told me anything about that. I did see a number of examples where people said they used a spacer and it worked great.
I wonder how their rear-ends are holding up....
I suppose this is wonderful proof that there really is no easy way out when it comes to cars. Buy the right parts the first time, regardless of money.
Damn that sucks. I have been running a ring gear spacer for about a year & had zero problems. I used a 2 series carrier & 3.42 3 series gears. Shop installed & set it up without problems. I have even ran a 12.9 @ 109 on it.
