Spid and sales order questions

[CG]

My spid says I have a G86 no spin. Longhair told me that was a detroit locker. I was looking at my original sales order and it says I have G87max trac...Whats that? The spid doesn't list the G87 and the sales order doesn't list the G86.

Id like to learn a little bit more about whats going on under my truck. I get some pretty big clunking under there at times. Is there a tag or numbers on the front and rears I can take pictures of and post em here for identification? Id like to know the ratios too. The original owner told me they were 4 something but I dont remember.

[Americanrider]

I have seen a G86 MAX TRAC option on an GMC longhorn spid before. It's just Dealer Double speak for a Detroit locker. The G87 must be a fat-finger mistake (typo)

[CG]

couple of pics...

[Burt4x4]

So this "clunk" does it generally happen right when you get rolling under power? Maybe when you start a turn from a stop?
If you get a "SlipBANG" then no more noise it sure sounds like a Detriot. Mine freaked me out the first time it happend.
I didn't know Detroit Lockers were around back then, then again never thought to try and find out..

[Yukon Jack]

My 69 K20 still has it's factory NoSpin (Detroit Locker)

The SPID says:

9514BB No Spin Rear Axle (and then maybe 4)

Behind the drivers side of the seat is a sticker that states:

This Driving Axle/s of this vehicle equipped with a NoSpin Differential for greater Traction, Safety and Economy

NoSpin postively rotate all driven wheels under power

Warning Elevate driving wheels when balancing servicing axles or brakes (See manual) Maintain uniform tire pressure

Detroit Automotive Products Corporation
11445 Stephens Drive P.O. Box 441
Warren, Michigan 48090 U.S.A.
Model No. KS-10

[special-K]

Does it have a Dana60?My`72 GMC has the G87 "Trac-Loc" listed on the SPID.It`s a limited slip.Mine`s great.If the clunk is from back there,it may be springs or clutches failing.Pull the cover and inspect it.That`s what Andy would say.Is yours a 4spd?

My`72 Chevy has the G86 "No-Spin" (Detroit Locker) in the Corporate rear and it`s a 4spd.I`m getting some scary clunks from that.I think the lack of "give" coupled by the rigid lock-up of a manual drivetrain is bringing out a problem with the trans or t-case.It occurs when I`m manuvering in 2nd or neutral,like parking,when I let of and am rolling.Sometimes it`s an outright "slip" then catch (clanky clunky).The problem started following rebuilding the rear and putting a locker back in.I actually put one in,had this problem,and then put another locker in...same problem.It only does it occasionally,I can drive it long trips and doesn`t slip while wheelin`.I expest to find an all but stripped spline/shaft situation.But,I can pull off just fine without any symptoms.Pretty strange,never saw this problem before.

[1969 GMC]

Originally Posted by special-K

Does it have a Dana60?My`72 GMC has the G87 "Trac-Loc" listed on the SPID.It`s a limited slip..

special k hit the nail on the head. it all boils down to what rearend you have. if its the eaton, its a detroit...if its a D60, you have a powr-lok clutch type posi.

[CG]

Ill have to take pics and post em. I really dont know much about this kind of stuff.

[special-K]

Me neither.Just fake it like me.No one will know,except Adam.That sucka know his drivetrainin`.

[1969 GMC]

Originally Posted by special-K

Me neither.Just fake it like me.No one will know,except Adam.That sucka know his drivetrainin`.

I am only 23, I know barely anything. I just absorb useless information.
Thanks for the compliment, special-k.


In my travels, I guess I should clear the above up, I have always seen the G86 rpo denoting a detroit locker with the Eaton rear, called a No-Spin. The G87 is Maximum Traction, or sometimes just posi, with the D60 rear. This is what I have seen.

[CG]

Finally got a couple of pics of my front and rear ends. Please let me know what these are, and are these strong or weak...Thanks

And it does give me the slip bang. I bought this from the original owner and he said its always done that. He took it back when he first got it and they told him thats just what they do...get used to it.


Mark

[1969 GMC]

Yup, if it is all original it will have the "No-Spin" which is the same as a Detroit Locker, just the commercial name.

The sales order must have been a typo, it's not like these codes are confusing or anything...lol.

Oh yeah, driving with a Detroit is interesting until you get used to it. Especially in snow!

[special-K]

Yeah,I agree,since it`s not a Dana60 and each of the two rears only came with the one optional traction device,both different.If you didn`t want a No-Spin(locker) you had to order a Dana rear.
Funny...musta been the same salesman that sold me my`92.When it came in and I ran it around the lot I told him it sure clanked bad at the rear.He told me the same exact thing.

[Burt4x4]

What I see is an Eaton rear end and a Dana44 front
My fater-in-law has a 72 3/4ton p/u with the same setup, got the big external hubs on the 8lug D44.

[CG]

Well it sounds like this stuff is pretty stout. Ill have to do some more crawling around under there. I want to figure out what gear ratio I have and I need to put some new springs up front to get it a couple of inches higher.

Thanks for all the help fellas.

[special-K]

Is there still an I.D. tag on the 2nd bolt up from center on the D44?It may be broken off or too rusty.But,my crapped-out eyes think they see something.

[duallyjams]

Back in the day you had to add additive the rear to stop the noise, now you just use synthetic and lockers are just noisy.

[earl87gta]

Only 3 gears came in that Eaton rear so if its original its ether 4:10s or 4:57. Most likely it’s the 4:57; 4:10s were not very common. They also cam in a 5:13 but you don’t see them very often. I love Eaton rears I keep a few of them in storage just incase a new project shows up.

[special-K]

Me too,I have a spare 4.10 w/locker.It`s going in my shortbed project instead of the 14-bolt that came with the 1t set I bought.