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dthompson
08-25-2015, 05:50 PM
I purchased a main shaft nut from Cobra Transmission recently. It did not fit. I have been arguing with the guy about it (trying to get a $9.00 refund). They are asking for a picture of the nut that does fit. I ended up reusing the original nut and its inside the sealed up transmission. If anyone has one of the factory nuts laying around and would not mind taking a picture using calipers to measure the width inside the threads, I would greatly appreciate it. Here is the picture of the wrong main shaft nut (the threads are too big).

64002

Mike Puckett
08-28-2015, 04:37 PM
It's slightly too big, right? It's for the truck version that has a larger diameter output shaft. We actually need the M5R1 transmission nut. I had that problem with Southern Gear several years ago and they pointed it out to me.

dthompson
08-28-2015, 06:27 PM
It's slightly too big, right? It's for the truck version that has a larger diameter output shaft. We actually need the M5R1 transmission nut. I had that problem with Southern Gear several years ago and they pointed it out to me.

Yes it was too big...

What's up with that? How is a guy supposed to know these things? :) why does a m5r2 rke in a tbird require an M5R1 mains haft nut?

Mike Puckett
08-29-2015, 12:05 AM
I suspect the kit is for the truck and not the SC. That accounts for the brass blockers in the kit. There are also some gaskets in the kit that the SC doesn't use and the truck does. I had to get my first one swapped out, had the same problem.

dthompson
01-11-2017, 08:34 PM
The M5R1 main shaft nut does fit. Cobra Transmission part number CT-306795 Main Shaft Nut $6.99

Hope this helps someone else!!!

Thanks
Derek