Just went for the first drive since the allofit swap, including 6 speed and 3.63 gears (i had a shop do the ring and pinion swap). Got back from a short autotune drive and went to back into my garage, after about 8 feet the rear of the car started to hop with a metal clinking sound that I can't think of a great way to describe the sound. I'm pretty sure i was backing in straight. Any ideas? Roast away.

 

diff seizing from the shop not setting the tension correctly? that's all i got.

 

all i heard was i put 3.63 gears in and a whole lotta other **** and something broke.

best of luck on figuring this fun one out, its a sad day when parts break

 

Thanks guys, I'll take it to the shop that put the diff together and ask him if he can figure it out. At least the car drives forward fine. I hope it's not me just not puttig everything in correctly. A forum friend suggested maybe it's the clutch that's grabbing and skipping, but i do want to figure it out

 

What about axles? Are they new? Did you reuse them? Also, the diff gears mesh differently when they are loaded in the opposite direction. I think it could also be an issue with incorrect backlash settings. I could see it doing that if it were too loose.

Which diff mounts did you use? I think that if this were the case you would notice in forward gears too, but yet again, the entire assembly is being loaded in the opposite direction. Recheck torque/bolts on diff mounts and PPF.

Also, are you using a OE torsen, or a different LSD?

 

Axles were purchased used from Treasure Coast Miata, so not the original axles but OE. New PU diff mounts. I'll check torque. Torsen is from a 97 donor car i got from junkyard, so I'm assuming it's OE. I didn't push it but I backed into my garage again two days ago and it didn't seem to hop as much, but it's hard to tell with noise too because the car is pretty loud.

 

Did the welds break?

 

JB weld never breaks, right?

 

I believe I was able to replicate the sound today while driving. I had to pull over on a narrow street to let a car come by the other way and stalled, for a second car rolled forward for a foot or two still in 1st gear and heard a similar sound towards the middle of the car. I drove for an hour today with no issues at all, nothing has blown up or flown out other than the ratchet extension i left somewhere in the engine bay that flew out when I went around a turn, but that's another story. Really puzzled by this.

 

I had a similar issue when backing up. It turned out to be a broken motor mount. (rubber was separated from the metal on one side)

Perhaps they left a motor mount loose?

 

I actually figured it out and should have posted. I have brand new everything including a reeeally grabby 6 puck clutch, so it was grabbing and skipping and chirping.