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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Rear Drivelines, Drive Axles and Gearing => Topic started by: talon57 on July 06, 2015, 12:57:30 am

Title: 1978 Chevy C20 Rear diff swap
Post by: talon57 on July 06, 2015, 12:57:30 am

I recently bought a 1978 chevy c20 for my first truck. It has a 350 with a Turbo 400 trans, heavy duty rear leaf springs and brakes, with a 14 bolt rear end and it has a open diff. I was wondering if i could swap a open diff for a posi/limited slip diff, and if i could how much would it cost, and i would most likely be doing the work myself.

Title: Re: 1978 Chevy C20 Rear diff swap
Post by: roundhouse on July 06, 2015, 04:43:03 am

You could swap the entire axle
If you could find another one with a limited slip that was in good condition

Setting up the gears is very complex and has to be done by someone with years of experience


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Title: Re: 1978 Chevy C20 Rear diff swap
Post by: Engineer on July 06, 2015, 07:31:18 am

Quote from: roundhouse on July 06, 2015, 04:43:03 am

You could swap the entire axle
If you could find another one with a limited slip that was in good condition

Setting up the gears is very complex and has to be done by someone with years of experience


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True in most cases but the 14-bolt FF is different.

If all you are doing is replacing the differential anyone can do it with only simple hand tools. There are spanner nuts that adjust the gear backlash. After replacing the differential leave the bearing caps hand tight. Adjust the spanner nuts to give specification backlash (I go .005"~.007" if no book is available) then torque bearing caps, recheck backlash, replace spanner locks and cover, fill with oil(important) and you're done.