Wedge Tr7/8 rear end ID RKC0100

[tr7andtvr]

These are the only numbers I can find on my TR7/8 rear end... What ratio do I have?

 

[TR3driver]

I don't know, but I'm guessing that it is like the earlier TRs. No matter what the case says, there are other gear sets that will fit and no guarantee that some previous owner hasn't change them. I sure didn't bother marking the case when I changed one of the Stags from 3.7 to 3.45.

So, jack it up and find out. Or, if you have access to a GPS and a working tachometer, work it out from that.

 

[tr7andtvr]

Easy enough, I was looking for the quick answer... Lol!

 

[justin_mercier]

stamped into the bottom of the differential (not cast in) should be an identifier CL = 3.45 CK = 3.08 CT = 3.27 CH = 3.9

That said, if someone changed the pinion and crown wheel, all bets are off and you'll have to figure it out on your own.

 

[tr8todd]

That's the part number for the housing. To find the ratio, you have to wire brush the underside of it until you see the numbers Justin listed stamped into the metal. You can also tell by the color of the nut holding the flange on. White, yellow, blue on the 5 speed rear ends, but off the top of my head, I can't tell you which color is which ratio. Basically if it came from an 8 its 3.08, if it came from a TR7 coupe, its a 3.90 and if it came from a vert, its a 3.45. Spin the input until one of the brake drums spins one complete revolution and count how many times the input spins. Thats you ratio.