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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Rear Drivelines, Drive Axles and Gearing => Topic started by: swilliams on February 01, 2015, 01:11:54 am

Title: 1986 C10 GU2 rear end
Post by: swilliams on February 01, 2015, 01:11:54 am

I have the stock GU2 rear end in my 1986 C10. I need to find out if it has 28 or 30 spline axles. What i have found says it depends on the year but does not go any farther. Thanks

Title: Re: 1986 C10 GU2 rear end
Post by: Stewart G Griffin on February 01, 2015, 10:13:40 am

i think up to 87, the axles were 28. (77-87)  After 88 they went to 30.  But if you get a 30 spline carrier the 30 spline axles from later 10 bolts and 12 bolt trucks can fit.

This is according to Randy's differential book.

They are a top notch shop.  i would suggest calling them for help. :
 http://www.ringpinion.com/

Title: Re: 1986 C10 GU2 rear end
Post by: swilliams on February 01, 2015, 01:40:44 pm

Thanks for the help

Title: Re: 1986 C10 GU2 rear end
Post by: Captkaos on February 04, 2015, 05:17:07 pm

The newer axles from a 88-up C/K 10 bolt are longer than 87 down R/V and C/K 10 bolts.

Title: Re: 1986 C10 GU2 rear end
Post by: swilliams on February 04, 2015, 07:24:34 pm

This is what i am looking at going with Detroit Locker 912A556 Detroit Truetrac Differential. It is for 28 spline axles. I want to be sure i  don't have 30 spline.

Title: Re: 1986 C10 GU2 rear end
Post by: Stewart G Griffin on February 05, 2015, 08:03:56 pm

Quote from: Captkaos on February 04, 2015, 05:17:07 pm

The newer axles from a 88-up C/K 10 bolt are longer than 87 down R/V and C/K 10 bolts.

i'm sorry i meant the 12 bolt 30 spline axles which originally came in a 73-81 truck.

Title: Re: 1986 C10 GU2 rear end
Post by: swilliams on February 06, 2015, 02:34:21 am

Thanks for the help.

Title: Re: 1986 C10 GU2 rear end
Post by: 78BIG-TEN on February 06, 2015, 09:19:04 am

I used a True Trac and it crapped out in just over a year,worm gears inside gave up,but I think they might have upgraded these units.It was on a 89 k1500 with 33x10.50 tires.It made a horrific noise in tight turns

Title: Re: 1986 C10 GU2 rear end
Post by: swilliams on February 06, 2015, 01:12:34 pm

What would be a better choice?

Title: Re: 1986 C10 GU2 rear end
Post by: Captkaos on February 07, 2015, 09:37:40 am

Some 12bolt 30 splines may require some massagine to get them to work, but yest they will go in.
As for a limited slip, it is going to come down to an individuals preference. 
I used Eaton Clutch type LSD,  I know of people using the newer Truetrack without issues

What is the intended purpose?

Title: Re: 1986 C10 GU2 rear end
Post by: 78BIG-TEN on February 07, 2015, 11:18:47 am

I like the Eaton clutch type as well,that is what I replaced the True Trac with and some 7 years later still going,

Title: Re: 1986 C10 GU2 rear end
Post by: Stewart G Griffin on February 07, 2015, 08:39:58 pm

Quote from: swilliams on February 06, 2015, 02:34:21 am

Thanks for the help.

No problem.

And i wonder if the 88-91 blazers and suburbans had the 30 spline axles?

Title: Re: 1986 C10 GU2 rear end
Post by: swilliams on February 09, 2015, 09:45:18 pm

My purpose is that since i have done some upgrades I spin the one tire. I am thinking that posi will help cut down on the tire spin.

Title: Re: 1986 C10 GU2 rear end
Post by: Captkaos on February 19, 2015, 11:37:19 pm

Quote from: Stewart G Griffin on February 07, 2015, 08:39:58 pm

And i wonder if the 88-91 blazers and suburbans had the 30 spline axles?

Yes they did...

It could make it spin both, but it should help...

Title: Re: 1986 C10 GU2 rear end
Post by: Rich84 on February 23, 2015, 01:34:00 pm

I used a 30spline carrier and axles out of an 88 and up truck in my 10 bolt..If I remember correctly the axles were about 3/8 of an inch longer. I had to go with a Buick Roadmaster drum to accommodate the longer axle.

Title: Re: 1986 C10 GU2 rear end
Post by: 78BIG-TEN on March 04, 2015, 01:06:00 pm

You might be able to find a good govv-lock out of a mid 80's suburban.Lots of them had it.I'm pretty sure they are the same

Title: Re: 1986 C10 GU2 rear end
Post by: swilliams on March 05, 2015, 10:26:04 am

I have herd that the gov-lock even though it was stock is not that good. But i am also not building a drag car. I only have but 2 local junkyards and our trucks have always been popular here and parts are scarce. But i do like all the options i am hearing about. Thanks.

Title: Re: 1986 C10 GU2 rear end
Post by: Captkaos on March 17, 2015, 10:27:09 pm

As long as you don't constantly beat on it you should be fine.  Right now my R10 with the turbos has a Gov-Loc in it...  It will be changed soon, but...