how to tell if limited slip?

[Knanthrup]

Ok, I didn\'t run my truck much before I stopped and parked it in the garage for the swap so I\'m not sure what rear (gotta look for a code) it is or if it\'s limited slip. A co-worker of mine who used to be a mechanic told me that with the rear jacked up, if you turn one wheel and the other wheel turns the opposite direction then it\'s limited slip and if the other wheel turns the same way it isn\'t. And, also were limited slips available in all ratios? If not which ones were they available in? (it will help me break down my options)



<b>1984 S10 2wd</b>


GM Goodwrench 350 crate


Dish top pistons


#450 Heads <b>|</b> 64cc <b>|</b> 2.02/1.60 <b>|</b> Ported & polished


Edelbrock performer intake


Mallory dual points ignition

[360hp350]

i thought it what the opposite if you spin one wheel and the other one goes the opposite direction it is an open and if they go the same way it is limited slip.

[duckaholic40sb]

if they spin the same way its posi, just think when u have posi most of the time they spin in the same direction no matter what, common sence... if they go opposite that means there are spider gears which means your have a \"1 wheel peal\"....but this isnt always true...the way to do it for sure is jack up in the center of the pumpkin and put the car in neutral, then get under the truck and spin the drive shaft...both may spin...so then what u do is lightly touch one of the tires with your foot or wedge a block under one...if the other spins with no problem...its an open \"posi\"less differential. most likly all of them had posi...most 4x4s had posi\'s u can always go get a posi from a camaro/firebird 7.5\" gear at a local junkyard

[whiner3]

i think the only way to tell for sure is to take the cover off and take a look.... probabyl a good idea anyway pull the cover off drain all the fliud then replace the fluid anyway... god knows when the last time it was changed... the diff is one of the most overlooked things in a vehicle... also if it is a posi it needs different fluid too

[stenaholic]

here\'s the codes



G80- limited slip

GU2- 2.73

GU4- 3.08

GU6-3.42

GT4,GQ1- 3.73

GT5-4.10



hope it helps

[Knanthrup]

On 2002-12-24 20:44, stenaholic wrote:

here\'s the codes



G80- limited slip

GU2- 2.73

GU4- 3.08

GU6-3.42

GT4,GQ1- 3.73

GT5-4.10



hope it helps



Excellent, that definately helps. I have one question though. There\'s one code for limited slip on the list but what about ratios on limited slip? Do they just have one code telling you it\'s limited slip and you have to check the rear for the code for ratio?

[spacecadet]

Would glove box numbers have both a G80 and a GQ1 if it were a limited slip w/ 3:73 gears?

[92sdime]

The g80 code and the rear ratio will be two seperate codes...So if you see G80 in the glovebox..you have [or at one point had] a limited slip diff..



EDIT..and mainly the diffs that came in in teh first gen trucks that had limited slip were 3.42\'s and up..the newer s10s have posi 3.08s..but I havent found a first gen that has it yet [not that Ive searched the world over or anything]

[spacecadet]

Thanks for clearing it up. I thought that was what it meant but I wasn\'t 100% sure. Just trying to find a quick way to find good rears when I go junkyardn\' next weekend. Don\'t really want to pull the cover on every S10. That would take to long. Space.

[Scotty_S-15]

OK, here is a relavent question: My \'94 full size PU has factory posi, but it\'s not like the old Limited slips. It only engages when one wheel is going 10% (= or -) faster than the other. So, when you check it by jacking it up, you can\'t tell. (wheels aren\'t locked together).

......... So the question is, what year did they start using this lame, half-assed posi? And I\'m presuming they did the same with the S-Trucks.......

..........another question, since the lame, half-assed posi works on a centrifugal principal, can it be easily defeated, so the posi is full time?

[mzoomora]

On 2004-06-08 22:49, Scotty_S-15 wrote:

OK, here is a relavent question: My \'94 full size PU has factory posi, but it\'s not like the old Limited slips. It only engages when one wheel is going 10% (= or -) faster than the other. So, when you check it by jacking it up, you can\'t tell. (wheels aren\'t locked together).

......... So the question is, what year did they start using this lame, half-assed posi? And I\'m presuming they did the same with the S-Trucks.......

..........another question, since the lame, half-assed posi works on a centrifugal principal, can it be easily defeated, so the posi is full time?



Those \"gov-lok\" rears you are talking about have clutch packs in them, so it shouldnt turn freely like a regular open diff. They used those all through the 80\'s and early 90\'s, and on many GM vehicles both the limited slip and gov-lok were available. It is what it is, and there is no way to change it. And when they break, they break into pieces, and it usually happens at higher speed engagement.

[Knanthrup]

Correct me if I am wrong, but I remember seeing a video showing the internal working process of a G80 rear and I don\'t believe it had any clutch packs. I remember something actuating when one wheel spun either 100 or 300rpms faster and it locked in place. I know my on G80, when it locks it locks and it doesn\'t come unlocked until you let off the power completely, doesnt seem like a clutch actuating. But then again I\'m not completely sure.



I know a lot of people talk crap about the G80 but I actually like mine. I don\'t have one in my street S10 but for my 4x4 I use it all the time. It has gotten me out of numerous situations and helped me out-wheel much larger trucks with open diffs. I think it\'s a pretty smart idea to have a locker that engages automatically, although manual would be better for an experienced person, I\'d rather send my mom out in snow or bad weather in a vehicle that automatically locks, cuz i doubt she would ever know when to use a push button locker. I guess they\'re weak or whatever but I haven\'t broken mine yet and pretty much all I ever do with the truck is wheel it. I think someone here summed it up nicely one time saying that GM had a novel idea but built on a smaller and weaker scale than it should have.

[mzoomora]

There is a clutch pack on one side only. The other side has a two piece side gear that actuates the centrifugal mechanism. I have a parts breakdown here that I can scan if anyone is interested. I personally think they are junk. We rarely sell parts to repair them because they break so badly, and usually take out everything else in the process.