I've got an 87 iroc with a 9-bolt. I changed the pinion bearings and am now ready to check my gear pattern. I am under the impression that I have to load the gears in such a way that I would have to apply about 40-50 ftlbs of torque at the pinion flange to rotate the pinion. I know that this is usually done by using the e-brake to cause resistance on the assembly, but my axle shafts are not currently seated in the carrier, nor are my brake assemblies attatched to the axle shafts. There has to be a way of placing the appropriate amount of load on the gears without the axle shafts in the carrier so I can check the pattern and make the necessary adjustments. I really do not want to assemble and disassemble this thing until I get an acceptable pattern. I was hoping someone may be able to fill in the blank for me. ANY help would be GREATLY appreciated. Thanks in advance.

 

I'm impatient, I know. Please help. Thanks.

 

you need 25 in/lbs of preload on the pinion. there's no need to check back lash or contact pattern if all you did is change pinion bearings. as for what you talked about, i have about as much idea as you do. there's no reason to do it.

 

That is such a relief. I thought I was going to have to keep popping out the rear race and shimming it until I got an acceptable pattern. Thanks a lot ede, you are one of the members that I was hoping would respond to this thread. I've got another question though. I know the preload specs for new bearings are 12-15 inlbs in the Borg Warner. But I don't know if that means ONLY the pinion / pinion AND carrier / pinion, carrier, AND axle shafts / or everything except the wheels. I did a search and looked at about thirty or forty threads, but can't find anything on the specifics. Thanks again man for the previous info.

 

 

It is just the pinion & pinion seal.

All the other stuff will add un-known loads.

RBob.

 

Thanks a lot RBob, that was the final thing that I needed to know. I'm going to go put this thing together tonight. And thanks again, ede.

 

Just for future reference, the way we used to apply a load to the gears when checking the contact pattern at the shop I used to work for was to leave the back cover off and use a pry bar against the flat part of the ring gear while another guy used a reversible 1/2" drill with proper size socket to rotate the gears both directions to establish the drive and coast patterns. Don't know if this is the most scientific way to go about it, but we never had one come back for improper setup using this method to check the pattern. As far as the pinion bearing preload, the specs you mentioned are for just the pinion bearing without the carrier or ring gear. They also usually say to add about 2 more inch pounds if the pinion seal is already installed. 12-15 in. lbs. is for new bearings, used bearings call for about 7-8 in. lbs.

 

Thanks for the reply, Pat. I just put this all back together last night. The prybar method is actually what I decided to do. Didn't use a drill though, I turned the pinion by hand. Although ede said that I didn't have to check the pattern, the marking compound was already on the ring gear from before I started this thread so I decided to give it a quick run. Pattern wasn't perfect, but it it was within reasonable limits. Pinion preload with just the pinion and seal was 14 inlbs after seating the bearings. I wish I could recall which member sited his/her use of strip stock from Home Depot to hold the pinion flange in place. He/she really saved my a** with that one, worked beautifully. I got a 3' x 1" strip that was 1/4" thick. I drilled the appropriate holes, removed my torque arm(had to change the bushing anyway) and stuck two screw drivers through the holes to hold the flange. Then I slid my floor jack handle(20" long) over a 1/2 drive wratchet and tightened down the pinion nut. When all of the play was removed, I started taking torque readings. Wasn't nearly as hard as I thought it would be. I just had to be really careful about not over crushing that sleeve. Thanks a lot for all the help fellas.