Help with R&P set up (LONG)

[texmotoII]

First off, I have done MULTIPLE searchs and found lots of information. Without going into a very long story(sheared ring bolts, chipped R&P, spun carrier bearing) on how I have arrived in the sorry situation that I now find myself, I will present the facts and request, er, beg for help/information.
-99 DII with ARB in the rear
-"used" GBR 3.91 gears, the ones with the threaded shaft on the pinion
-all new bearings
-complete lack of experience and making/reading gear patterns
-unable to locate anyone locally willing to do R&P set up
First 2 attempts have failed. After attempt #1, constant noise on acceleration, starting at about 10 mph, increasing with speed, peaks at about 70mph. Drove a total of about 100 miles in this set up. (Note: I do not have an inch-pound torque wrench, and still have not been able to locate one locally.) Backlash was 0.011. Torque to turn was "loose." Pattern was unclear.
Borrowed a stock DII third. Practiced reading a pattern, checked backlash (0.0025 BTW), and got a better feel for the torque to turn (with the pinion seal in, however).
After attempt#2, set backlash to 0.006. Torque to turn now "tight," slightly stiffer than the borrowed third. Pattern was inconclusive (at least to me and my helper. Yes, we are sucking ass at this, I know.) Whole host of sounds, much louder than before. Diven about 4 miles on the test run, vehicle now parked awaiting attempt #3.
SO, I know stock R&P call for backlash of 0.003-0.007, and I have read that GBR 4.11 should be 0.008 - 0.012, so what about GBRs 3.91s? What range on the backlash?
Is there any way to get an accurate pinion bearing preload measurement without a inch-pound torque wrench? I still have a couple of places to try tomorrow to buy one, but if I have to, I will order one on line. However, I was really hoping to finish up this project before wednesday, when I'm back to work. Any suggestions or am I just SOL with out the wrench?
Lastly, before the flaming begins, two "pro shops" have worked on this rear end during the past 2 years or so with mixed results. IF there was someone local worth a damn, I would have taken it to them long ago. :banghead:
David

 

[mchomes]

find a good shop. Your time has to be worth more than that. I took mine to a custom off road fab shop with good instinct reading patterns. Many searches show difficulty making a typically acceptable pattern in rover diff. These guys put it together at least five times until satisfied, only charged me 275 including oil, pulling third & driveline, removing front driveline until Bill sent the front diff, axles, test drive, welding on diff covers, putting up with me helping, etc. The thing is quieter and smoother than with full stock setup. btw gbr 4:11 detroit, tt, rovertracks f&r. Note: GBR green diff ordered complete leaks out the pinion seal. Im sure bill would fix it, but I don't feel like bench pressing that stinky biatch again-besides, everything else leaks.
Good luck!

 

[texmotoII]

There is no good shop locally. There are two local (DFW) independant Rover shops; neither mess with R&P setup. The local stealership doesn't do it either. The gear shop that "everyone" uses worked on it about 18 months ago. Net cost after multiple problems was $800 (including a new R&P), and the whole thing self destructed while driving down a city street. BTW, that price includes me pulling and replacing the third. So far, I have installed three different TTs, and all of these have been fine. But I didn't have to mess changing the pinion on those. I have also checked with a couple off road shops, but they "don't work on Rovers" and wouldn't even think about touching mine as they did not sell me the R&P.

 

[barefoot]

call gbr?

 

[RichardS]

Suggestions:

Bicycle shop may have an inch pound torque wrench (Park tools makes them for bikes.) Sears may also have one small enough.

Make sure you are preloading the carrier bearings as well. The method I used was to tighten the ring gear side until there was almost zero backlash, then tighten the other side enough to open it up to the correct backlash. If you do not preload here the clearance can open up under load and cause trouble.

Do you have a set of pinion shims or are you using the original one? This is likely where your problem is, the pinion is likely too deep or too shallow, causing the pattern to be wrong, causing the noise.

What are you using for marking compound? I had a hard time reading the patterns on mine until I bought some of the GM yellow marking compound. Might help to mix a bit of 90w with that to get a clear pattern.

Also when you are trying to get a pattern spin the ring gear with a wrench while applying pressure to the pinion with your hand. For me this made the pattern clearer than when spinning the pinion.

If all else fails drop them in 5gal buckets and ship them to GBR, he will certainly get them set up right for you.

 

[texmotoII]

Thanks RichardS. I have been to or called 12 different places looking for marking compound and the proper torque wrench, including Sears, bicycle shops, Napa, ect. No one around here has either. Almost no one even knows what gear marking compound IS around here. I can order one (wrench) on line, but was hoping to finish this up tomorrow, but thats probably not happening. BTW, I have the shim pack from GBR. Forgot to ask Bill about the backlash for the 3.91s and now he's not answering. I'm using spray on blue machining dye. It works, but as I found out, the surfaces must be spotlessly clean first. Any (good) alternatives to the torque wrench for setting the pinion preload>

 

[RichardS]

Bummer, the local GM parts counter here had the marking compound in stock. It works much better than machinist's blue, that what I started with.

Hopefully you are done by now. If not, one alternative to a torque wrench is some scrap metal strap, a fish scale, and math. Bolt a strap across the yoke, pick sum number of inches and drill a hole for the fish scale that far from the center line of the pinion. Say you choose 6 inches, when the scale is connected there and reads 1lb the torque is 6 inch lbs. A bit of a PITA but it would work.

 

[peter sherman]

I bought my torque wrench on feebay. snap on dialameter pretty cheap
i used rupps recipe of gm & white lith mixed.
I don't have access to my notes & its been a while!
for the marking compound check semi gm truck service places [easy for me to say]