MontanaKid

I'm putting a lsd back together from an 85 GSL-SE. I found a dif from an 88 and used a combination of the discs and plates to get one decent lsd for my project. If some one could supply me with torque specs, back lash, and anything else use full. I'm sure this is in the 1st gen Archive, but I couldn't find it. So if some one could provide me with a link or anything I'll be much grateful. One more thing, off subject. I need new widow channel stripping and seals for my SA. Any Ideas. Thanks very much?

trochoid

iTrader: (6)

Specs and assembly are in the FSM, see sog for link. Window channels, Black Dragon.

MontanaKid

Thanks trochoid.

steve84GS TII

Make sure you have some GM gearmarking compound(there is no substitute),a dial indicator and a full understanding of hypoid gear setup before you slap it back together.There is no room for error with rearends,and only a slight amount of tolerance variation when setting gear depth,pattern,backlash and preload.

Backlash is .09 - .11 mm.
Minimum backlash is .06 mm, with no more than .07 mm of varience between the highest and lowest backlash measured,at 4 different points along the ring gear.

Ring gear bolt torque is 51 - 61lbs ft....be sure to tighten in small increments and in a criss-cross pattern.
Be ABSOLUTELY sure the gear and carrier are clean and smooth.This is the number one reason for wild variations of backlash when you start setting up the final clearances.

Pattern is like any rearend.You want the mark to be centered between the root and the face of the gears.(top to bottom) The pattern can be towards the inner or outer edge of the gear to a point,without any problems,but the pattern must never be all the way to the bottom of the "valley" between the teeth.Be sure to recheck pattern and backlash after any torquing,adjusting or verification of any of the other adjustments.All the adjustment aspects of a rearend setup will affect the other's in some way or another.Thats why it can take so damn long to get it right.

MontanaKid

Hey thanks Steve. That's some good advice that I need. I've never messed with rearends. I've got the tools and the know how just haven't ever needed to get into one till now. It's seems very simple just "extra tech". I can assure you it isn't going back together until everything is in specs. I can't afford to destroy everything. Thanks again man. Oh yes, gorgeous car. Nice Fab job on the light assemblies!

MontanaKid

ooooo.. Coulda sworn that I had an outside micrometer big enough for getting the measurements on the differential bearing caps, for preload. but I don't. Do any of you guys have any numbers combining the pinion preload and differential preload together so I could just get it off the pinon with a dial indicator. I set the drag on the pinion itself to 10in/lbs and the oil seal is about 1.5in/lbs. If I woulda measured stuff before I took it apart I wouldn't have this problem. dog gon it!!!

steve84GS TII

Its kinda tough to determine carrier preload through the pinion,since there will always be some friction drag from the gears sliding.

When I setup Dana axles,I just cram the carrier preload as tight as I reasonably can,using the shims.Since we have adjusters,you just have to crank them down.According to everything Ive read and heard,its very,very rare to get the carrier pre-load too tight.....most guys just crank them down tight with a 1 foot long tool.
The two carrier bearings have totally different lives anyway,considering the pinion is always trying to push the carrier to the left when the power is on.The left bearing has to cope with massive thrust loads while the right bearing is just hanging out.The main thing is to eliminate and slop that would allow the backlash and pattern to change.This is accomplished by first finding the correct backlash and pattern,then cranking the carrier preload adjusters down in exactly equal amounts.This will snug up the bearings without shifting the carriers postion in relation to the pinion.

Here is an excellent basic guide to gears by a top seller/installer.I used this as a beginners guide until I really got the hang of it.It covers the crush sleeve/carrier adjuster type of rearend that we have,since Toyota trucks and many other 4x4's use that kind.Print it out and keep it handy......

http://www.jedi.com/obiwan/jeep/ring_pinion_setup.pdf

trochoid

iTrader: (6)

Steve, your knowledge continues impress me. Thanks for posting the link to the diff PDF. Rebuilding diffs and trannys are 2 skill sets I would like to add to the talent pool.

steve84GS TII

If your the logical,left brained,left handed type like myself,then doing rearends is right up your alley.
Its a very precise type of job,but most people are scared away because of the delicate balance that is present between the 5 main settings.There just isnt any getting around the fact that you cannot fudge anything,there are too many overlapping tolerances in a rearend.One little shim or one little crank of a screw can trash the whole job.Many first timers either dont have the patience or the solid know-how to get it all right,so they either give up and pay to have it done,or slap it together in a "so-so" manner.....and then it fails.

I taught myself rearends a couple years ago because I was just getting into building my own rock crawler.In the past,I always used a buddies rig,so money was never an issue.When it came down to building my own rig,I couldnt scratch up the 1000 bucks needed to setup front and rear gears everytime I made a mod or popped a diff.Its a skill that has saved (and earned) me a lot of money!

MontanaKid

yeah! I greatly appreciate it. I used a 10 inch spanner after reading the info on the link yoiu provided. That's good stuff. Thanks. So I cranked the puppy's down pretty good, and used some compound to check the mesh and it looks great. So I torqued the caps and rechecked my backlash and I got .003in. on one side and .005 in. on the other with the averages at the other two points on the ring gear. So it's nicely in spec. I sure hope it holds well. You know I never quite trust myself. But everything measured out right so it should be good. Thanks again Steve and Trochoid!

MontanaKid

So I tried to put my rearend together last night. After sliding the third member into the housing to my horror it wouldn't go past the ridge that the back is welded to. it would just make it past the mounting face on the housing then it would hang up on the "pilot nodules" on the dif caps. So obviously the spread was to far. So I cleaned the mess up of sealer that was smeared everywhere from trying to fenagle it in, and started over. I turned out the adjuster two notches each and back in one each. still didn't fit. So I turned them out two more and in one each and it fit this time. Checked my back lash and it was alittle to much so I turned in the left side one notch and rechecked and it was perfect and then the whole thing slid right into the housing. And if I remember right. when I pulled it out I recall feeling a little catch on the endcaps on that lip and I felt the same catch again putting it in and out afew times. ha ha( thats what she said) just kidding couldn't resist. anyway. I'm areally suprised at how easy and far the whole case will spread. The first time I tightened the adjusters I didn't even reef on them that hard. And to make it fit they are really just snug. The rotational drag at the pinion is barely any different between the two times when it was too tight and now. So that's why the manual calls for you to measure the spread on the bearing caps, cause just like steve said you can't really tell through the pinion. and ya can't.