Hey guys, I've been following this stuff for a while now and I am still not sure about this one. When you set the preload, you have to use in-lbs torque wrench with 32 (or 36mm, don't remember) socket. I've read some people on this board saying that when dealing with very small torque values such as these, using 1/2"F-3/8"M converter will distort the readings. I am not sure what the argument of that discussion was (or if there even was one). So I am about to do rebuild/gear swap on my rear end. Ordering parts next week. How should I go about dealing with the pinion preload? As always, any help will be greatly appreciated. tia

your best bet is to buy a HELMS manual. NOT a hayes manual. go on evilbay and look for a service manual on your year model car.
the hays manual covers about 4 or 5 years of car and with various models and is about 1 in thick.
a helm manual covers that year model only and is about 2 or so inches. they have all of the tq specs you will need including what tools to use.
you may not be able to get the EXACT GM tool reqd but a standard similar equivilent will do.

Richard, I have Helms manual for every car I own. (and for Trailblazer it is 2 volumes, each 2" thick )

I thought the question was pretty specific. Bearning preload is measured in in-lbs. 0-250 in-lbs torque wrench is 3/8" drive. Socket that goes over the pinion nut (correct name?) is too big and only comes in 1/2" drive. 1/2" drive torque wrench only does 25-150 ft-lbs, which is way too much for bearing preload. If you use the converter to use smaller tq wrench with larger socket, it will screw up torque reading.

So what do people do in this circumstance? Granted, I haven't looked at the manual yet on this (it's not with me at the moment), so maybe it has all the answers I am looking for. But in case it doesn't, I am looking some advice here

i wouldn't worry too much about any distortion or error in the readings using an adapter. the correct socket size is 1 1/4 but that might be a bit hard for you to come buy. you should use a new nut ,but again that might be hard for you to get. put a bit of liquid tefelon sealer on the splines when you put the yoke on. use a dial type torque wrench.

I have always used an adapter and never experienced any problems. I realized there would be a error in the exact amount of torque applied but i used what I had.

the last one that I did was about two years ago, and IIRC the spec was somewhere around 15-21 in-lbs for continuous rotation.
That torque will sneak up quick. If you go over it, you will have to restart and replace the crush sleeve. Make sure everything is lubed with a lighter oil upon assembly. and as preload is being applied to the bearing make sure you spin it between tightening sessions.
The only thing I really vividly remember was having the rear out of the car, A 36" pipe wrench on the flange (locked to the ground), using a pipe for leverage on the ratchet I was using to tighten the pinion nut, and damn near flying across my garage when my POS craftsman ratchet broke.

i think my TQ settings were around 6-12 ft lbs per the dial tq wrench. we used a step down adapter on the dial wrench and i couldnt see where it would hurt specs any. also being they give you a small amount of range in the tq specs makes for no need of a direct number to worry about.
when we did the setup on mine last weekend my friend made this VERY nifty tool ya might wanna try. it was 2 pieces of pressed wood about 1½ or so in leingth and about roughly 6 in wide with a hole cut for the yoke to sit in comfortably. i was wondering how we were gonna get the thing apart and together without a vice. all i gotta say is that thing was a massive help esp when his impact wouldnt crush the sleve . being a 9 bolt sleve is shorter than a 10 bolt sleve made things a lil more complicated.
VILeninDMi posted about the books not knowing you had them already. my friend FINALLY found a small dial indicator tq wrench from KD tools that was exactly whet he needed for measuring tq specs at the yoke. if ya want i can ask where he got it from. i do know its made by KD tools.

thanks for the info guys. Looks like I'll have to go out and buy another torque wrench. The two wrenches I have are clickers.

Richard, I didn't quite follow your design for the nifty tool. Can you elaborate on that. I was thinking of what I was going to do there myself. I think I even remember people on here using PVC pipes, instead of one of those infamous "J" tools.

Can you guys also confirm that I can check for contact pattern (shim sizes) without setting the preload (as long as pinion nut is relatively tight). I also found some company (in chevy high performance or hotrod) that sell test bearings which are slightly larger in ID so you don't have to press them on while doing the pattern tests. Is it worth it checking them out, or should I just press out old bearings and use something like brake hone to make ID slightly larger?

i would play it safe and stick with hte stock required bearing. ya start honing and you might wind up with a mis align somewhere and this could cause issues.

as for the tool. he cut 2 pieces of 1/4 in thick pieces of pressed ply wood. the with was about 6 -8 inches in width, around 1½ ft long. i forgot how he stuck them together, i think he used roofing nais so the tips wouldnt pertrude thru the other side.
take a close measurement of your yoke and cut that diameter at one end about 2½-3 in from the very end.

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"something" like this. if you want i can go get exact measurements. excuse the poor drawing and the dotted lines in hte center are there so it would actually come out somewhat right.

if you set pinion depth correctly you shouldn't have a problem with the contact pattern as far as needing to remove and reinstall the pinion gear. if you can't get a new nut i'd try real hard not to install the used one any more than i had to and i'd use thread locker on it. easiest thing to get mock up bearings is to hone out your old one. great for checking pinion depth then press on the new bearing and you should be all set.

That is what I did on mine ede. I clearanced out the old bearing, and used it to check depth, then when I got depth, contact patter, and backlash right, pulled it all apart, installed the new bearing and put it all together, and did one last check to make sure it was right...

Works out really well...

thanks, guys. Sounds like I almost know what I am doing.

Just to be clear. When you test depth/backlash/pattern, do you need to destroy the crush sleeve and set preload correctly, or is tightening pinion nut going to be enough?

to check pinion depth you just putthe pinion in, no cruch sleeve and no nut. i push/pull it forward with my hand and measure pinion depth. after you have correct shim for the pinion depth install the good bearings, not honed out "checking bearings", crush sleeve and install the yoke and nut. tighten nut to correct preload. install carrier and check back lash then lastly check contact pattern. the pattern should be good if everything else is.