Rear gear change

[john1977]

Can anyone tell me how difficult it is to change the gear ratio in a 77 C3 & where you can find like 3:50s?

 

[JohnZ]

This job is best left to pros with the right pinion depth setup tools and experience; the pinion and carrier bearings and seals should also be changed as long as it's torn down. Depending on what ratio you have now, you may have to buy a new Posi unit as well, although all the originally-available '77 ratios (3.08 up to 3.70) used a Series 3 carrier; if someone previously has installed a higher or lower ratio than those, you'll need a new carrier. Gearsets are available from many suppliers; expect to pay $300-$400 for gears,bearings and seals, plus shop labor to tear it down, rebuild and re-install it, and I'd recommend rebuilding the Posi unit as well while it's apart (you only want to do this job once).

 

[Crickett]

Yup, definately a job for the pro's!! :TALK

 

[Scooter76]

As said above the setup tolerences are critical. It's not hard to do the swap but getting the setup correct can be time consuming & you do need some specataly tools. I would say that if you planning to do it only once- pay someone to do it. If you plan on doing more gear swaps in the future & have the desire to learn how to do it, then I would attempt it. This is the route that I went. I have done several rearends & I get better at it each time. Have a good one!

 

[GerryLP]

You can save a bit of money by removing the third member (sometimes called the pumpkin) yourself. By the time you extract it, clean its exterior, and take it to the shop it will be in such manageable package that it will cut the cost somewhat. That's what I did, and the guy I took it to charged me $100 labor (I had bought the overhaul kit from Ekclers and the pinion and ring from a Dana parts supplier in Nevada).

The hardest tool to find needed for the gear swap is the spreader tool, and I couldn't find anyone that could loan it, sell it, nor rent it to me.