Coupe Rear Gears

I'm celebrating 45 yrs of coupe ownership by switching the ring & pinion set from the mid-range ratio to the plains ration (4.11). I've done about everything on these cars, but never rear end surgery.

As it happens, getting the rear axle out of the car is quite easy. After lifting and securing the car, drain the gear oil, remove the wheels, put a jack under the differential case. Then detach the axle from the rear springs, disconnect emergency brake cables and the hydraulic brake line, and take apart the spring shackles to lower the springs. The assembly can be pulled back - no need to disassemble the universal joint – and rolled out on the brake drums. Put the wheels back on to make moving it around easier.

Here's the unit after removal from the car:

From Rear axle

I rolled it out to the driveway and scraped off the accumulated grease and dirt with a scraper and wire brush. I then washed it down with kerosene. I plan to put a good coat of frame paint on it before putting it back in.

One thing I learned in the process: Not only were the axle ends painted to indicate what gear set was inside, so was the differential case. In this case, the paint was green to indicate the mid-range gear set.

Axle paint:

From Rear axle

Case paint:

From Rear axle

I put a dab of blue paint when done to indicate the high range gears.

I'm not brave enough to attempt to switch out the gears. Old car friend and master mechanic Peter Brown will do that work, but I do hope to watch and document. Peter picked up the assembly today and will get to it sometime next week. We'll also replace all bearings and seals as long as we're in there.

When done, I hope to gain top end speed, improve gas mileage, and lessen engine wear. We'll see. Andy Lee did the same to his coupe and says it made a big difference. If so, I have another set of gears to do the same with the cabriolet.