M80 pinion has extra length after thread?

[PappaYeet]

I've just bought a 3.7:1 Motive Gear set to put in my VT Series 2 with M80 diff. However the new pinion has an extra length after the shaft which I imagine would hit the tailshaft flange. I've checked the old gear ratio and the numbers stamped on each gear and it's definitely an M80. Bearing surfaces all have the same diameter, but the pinion nut thread is larger on the new gear.

Is this some sort of weird crossover year thing? I've emailed Motive to see what they think. Could probably just cut it off but I imagine the steel is fairly hard...

 

[harrop.senator]

Looks to me like someone's cut your original off to fit a 4 bolt flange.

Or is a strange cross over but the extra piece is normal.

 

[Immortality]

That extra piece is the difference between early M80 (VT) that still used the 4 bolt flange style driveshaft coupling and the later M80 (VX onward) that uses the rubber donut type coupling. The extra bit sits inside the donut/driveshaft to support it so the coupling is only taking load in the rotational direction and not supporting the actual driveshaft weight.

I'm not actually sure if Motive supply both types or if it's easier to cut off the extra piece and yes the steel is a lot harder and takes a bit of effort to get through.

 

[EYY]

Just cut it off with a grinder - standard procedure. Will take less than a minute.

 

[PappaYeet]

That extra piece is the difference between early M80 (VT) that still used the 4 bolt flange style driveshaft coupling and the later M80 (VX onward) that uses the rubber donut type coupling. The extra bit sits inside the donut/driveshaft to support it so the coupling is only taking load in the rotational direction and not supporting the actual driveshaft weight.

I'm not actually sure if Motive supply both types or if it's easier to cut off the extra piece and yes the steel is a lot harder and takes a bit of effort to get through.

Thanks, makes sense. Guess I better get some cutting discs.

 

[Immortality]

I'll add these here for future reference.

 

[PappaYeet]

Did this a couple weeks ago but forgot to post. An angle grinder and running water, took less than a minute.