ok so i have a 86 nwc t5 (v8 one) and 5th gear keeps walking past the snap ring like its nothing. ive tried new snap rings, the locktite stuff and 5th gear just keeps doing its own thing. so i was wondering other then buying a new main shaft how to fix this problem, then i realized it looks like the snap ring groove is a bit rounded. so my question is, can i grind that snap ring groove down, even a little deeper, to stop 5th gear from walking past the snap ring? and it not mess up the trans?

 

The surface of the mainshaft is hardened and challenging to machine.

The solution used by Tremec on some T56 models and all TR6060 is some of the lock rings were replaced by half-circles with a ring around them. But, without something behind the ring, you lack something to hold that ring.

Since you're machining anyway, I would figure out what fat lock-ring would work in a slightly deeper, wider groove. Maybe 0.030" deeper and whatever it takes to sharpen up the edge of the splines facing the ring.

 

ya i have a drimmel that spins at 10,000 and some pretty pricey cut off wheels. looking at the spines they are a little rounded. not trying to do to much cutting but i need my 5th gear back permanently.

 

A dremmel and cutoff wheel won't touch that. You will rip thru wheels without removing much, if any metal. Also, with a dremmel, you will have a hard time (you can't do it) holding the tolerances that a part like that will require. Start looking for a WC T-5