8 3/4 rear end

74roadbird · Post by **74roadbird** » Sun Nov 17, 2013 1:53 pm

I put an 8 3/4 rear in the 74 Runner, and when we drained it, the fluid didn't look too good. A friend who is a mechanic and owns a shop said he didn't think that the gears were turning as smooth as they should be. In spring we'll rebuild it and put in a posi right away. Is Year One or Summit a decent place to get the new parts, or am I better off with a speed shop like Mancini Racing? I've used Mancini, but they seem a bit pricey for big stuff. I live in southern Wis., if it makes a difference.

kenny · Post by **kenny** » Sun Nov 17, 2013 9:56 pm

i like randys ring and pinion web site by the same name

71_bronze_gtx · Post by **71_bronze_gtx** » Mon Nov 18, 2013 1:43 pm

The important part in setting up the ring and pinion is getting the correct amount of mesh. Too much results in a high wear rate and possible overheating. Too little is almost as bad and also results in a high wear rate, but the wear is in different spots on the teeth. It pays to find someone who knows the correct method of shimming.

I would say call Mancini and ask who makes the most durable gears. Then shop around, including ebay. Also, someone on this site may have an opinion on who makes the best. It may not really matter if you're not going to flog it with a big torque engine.

72bluNblu · Post by **72bluNblu** » Tue Nov 19, 2013 2:49 am

Cass, aka "Doctor Diff" is the guy to talk to. Great guy to deal with and VERY knowledgeable. Pretty much has everything you need to go through an 8 3/4.

http://www.doctordiff.com/

rr6pak · Post by **rr6pak** » Wed Nov 20, 2013 12:38 pm

72bluNblu wrote:Cass, aka "Doctor Diff" is the guy to talk to. Great guy to deal with and VERY knowledgeable. Pretty much has everything you need to go through an 8 3/4.

http://www.doctordiff.com/

I second this choice. Well know to the Mopar community.

471Magnum · Post by **471Magnum** » Wed Nov 20, 2013 8:04 pm

I use Cass for all my differential stuff. Great guy with competitive prices and customer service second to none.

road chicken · Post by **road chicken** » Thu Nov 21, 2013 2:58 pm

The guy seems to be on it.

If you have any problems setting it up I had a Trans-Master in Watertown set up my 4.10s in my 8 3/4, $500 with the gears and labor. He also machines a spacer to get rid of the crush sleeve. The pattern was perfect and runs smooth even at 140 mph- and that puppy is spinning

One thing I saw, and bought from Cass was the brake caliper mounts for the 11.75" Cordoba brakes. I had been looking in boneyards for 2 years for these. The $90 for the new units is money well spent.

Road Runner Nest

8 3/4 rear end

8 3/4 rear end

Re: 8 3/4 rear end

Re: 8 3/4 rear end

Re: 8 3/4 rear end

Re: 8 3/4 rear end

Re: 8 3/4 rear end

Re: 8 3/4 rear end