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-   -   pinion gear assembly (how to shim) (http://www.hotrodders.com/forum/pinion-gear-assembly-how-shim-220273.html)

bugget_jr 06-06-2012 02:14 PM

pinion gear assembly (how to shim)
 
Hi, I got a pontiac 8,2" 10-bolt b-o-p axle in my firebird-67, and I bought a differential, ring gear and pinion gear. The ring and pinion gear have not the original ratio so I have to "re-shim" those when assembling the axle.

But I kind of got stuck at the beginning thus I don�t know the proper way to shim out the pinion gear. The inner bearing of the pinion gear is really hard to assemble, It�s requires tapping on the bearing, but if I do this it will be really hard to assemble more shims if it�s required.

So the question is: How do I assemble shims and bearings in a proper way (Observe that I gonna have to assemble more shims later, so it�s not the final assemble)?

Grateful for all help I can get :)

68NovaSS 06-06-2012 02:37 PM

Use a differential case spreader, you can probably borrow or rent one from NAPA, Advance Auto, and other parts stores. You can also make your own if you have a small welder. Google it. Look here and here to see what they look like, not cheap to buy...

lmsport 06-06-2012 03:54 PM

You can get a set-up bearing to make changing the shim a simple process. It has a slight oversize ID so its a slip fit on the pinion. You can do it yourself with a die grinder.

bugget_jr 06-11-2012 03:25 PM

thanks. I also wonder about backlash. Mostly about the differential side gear backlash that Iīve seen people do on video (on non-BOP axles). I think I know how to measure it but not how much backlash I should have, and how to correct it. I have a new differential but the old gears, so do I have to check this? Iīve googled it with no success.

Also anyone know what backlash I should have on ring gear to pinion gear? Iīve read on internet and found that it should be 0.005" to 0.009" but I also found on other sites that it should be .006" to .010". But either way it just a guide-line for a proper pattern check, right?

lmsport 06-11-2012 04:00 PM

You will have to check and adjust backlash by doing the following:

Take the diff without the ring gear mounted and install in housing with bearings.

Find the total shim height that makes the carrier bearing preload about zero, ie you can pull the carrier in and out with the shims installed but it takes some effort.

Add .008" to the shim height you determined to achieve carrier bearing preload.

Divide the total shim height into two about equal shims and mock up total assembly with pinion and ring gear installed.

Check that the pattern on the coast side of the ring gear is basically centered on the tooth and that the ring gear backlash is .008-.012".

prostreet6t9 06-11-2012 06:20 PM

Your inner Pinion brg should be BCA#HM89449. Buy a Extra brg and put a sanding wheel on a die grinder and hone just enough off the ID that the Brg will slide on and off.

During your initial set up leave your Seal and crush sleeve out and just set the pinion preload with the nut. Now you can play with your pinion depth and backlash without going thru crush sleeves.

You can start with your original pinion and carrier shims to get in the ball park and adjust from there.

When you get a good pattern pull it apart 1 more time and install the seal and crush sleeve. Remember to keep your preloads and backlash the same during the setup so your final result stays the same.

bugget_jr 06-12-2012 02:34 PM

thank a lot! really good step-to-step explanations about the pinion and the backlash.

prostreet6t9 06-12-2012 02:40 PM

Quote:

Originally Posted by bugget_jr
thank a lot! really good step-to-step explanations about the pinion and the backlash.

If you get stuck on the set up.. post a pic of your gear pattern and we can get you going in the right direction.

Take your time and pay attention to detail. :)

bugget_jr 06-13-2012 10:52 AM

I was to begin assembling the rear end to day but was really worried. Because Iīm a beginner Iīve got a really hard time to figure out what specifications I should follow. Is this specifications something I could follow http://www.cardomain.com/ride/204363...-9#20436320232 (both on pinion preload, backlash, ring gear torque and cap torque)?

Iīm currently stuck at the preload drag of the pinion nut. According to the link above it should be a drag between 12-15 lbs (thatīs the same as lb-ft, right?). Can that be right? And if it is, should I use this preload drag on both the measuring stage and the final stage?

If the specifications above isnīt reliable is there someone out there knowing where to get some reliable specifications, or maybe can tell me?

prostreet6t9 06-13-2012 12:22 PM

Quote:

Originally Posted by bugget_jr
I was to begin assembling the rear end to day but was really worried. Because Iīm a beginner Iīve got a really hard time to figure out what specifications I should follow. Is this specifications something I could follow http://www.cardomain.com/ride/204363...-9#20436320232 (both on pinion preload, backlash, ring gear torque and cap torque)?

Iīm currently stuck at the preload drag of the pinion nut. According to the link above it should be a drag between 12-15 lbs (thatīs the same as lb-ft, right?). Can that be right? And if it is, should I use this preload drag on both the measuring stage and the final stage?

If the specifications above isnīt reliable is there someone out there knowing where to get some reliable specifications, or maybe can tell me?

NOT THE SAME.. it needs to be INCH pounds of rotating preload.

So tighten the pinion nut till it take's 12/15 inch pounds to rotate the pinion.

prostreet6t9 06-13-2012 12:30 PM

Ring gear 55lbs clean threads with red locktight
Main caps 60lbs clean threads with red locktight in final assembly. No need to take the bolts to a full 60lbs during set up.

prostreet6t9 06-13-2012 12:33 PM

Quote:

Originally Posted by bugget_jr

should I use this preload drag on both the measuring stage and the final stage?

If the specifications above isnīt reliable is there someone out there knowing where to get some reliable specifications, or maybe can tell me?

Keep all your preloads the same during initial set up and final assy. This will help with your pattern staying the same when you get to final assy.

bugget_jr 06-13-2012 01:05 PM

thanks again. How about the side-bearings preload? Should I adjust it after the gear pattern check, is that possible? How do I know when I got the correct side-bearings preload?

As I understand it from other internet sources: if I have a pinion preload of 15 lb-in then I should set the side-bearing preload such that the preload drag on the pinion is 53 lb-in (with a gear ratio of 3.55 (15 times 3.55 = 53)).

and again, thank you for all help. Really appreciate it. :)

prostreet6t9 06-14-2012 11:49 AM

Quote:

Originally Posted by bugget_jr
thanks again. How about the side-bearings preload? Should I adjust it after the gear pattern check, is that possible? How do I know when I got the correct side-bearings preload?

As I understand it from other internet sources: if I have a pinion preload of 15 lb-in then I should set the side-bearing preload such that the preload drag on the pinion is 53 lb-in (with a gear ratio of 3.55 (15 times 3.55 = 53)).

and again, thank you for all help. Really appreciate it. :)

Do you have the pinion in the housing and have you tried setting the carrier in the housing yet? If so.. how tight does the carrier fit in the housing?

bugget_jr 06-16-2012 06:03 AM

Iīve assembled the pinion and tried to assemble the differential with the orginal shims but it wouldnīt fit. Then I re-shimed it so the shims was about 0.04 inch less than original. With those shims it would fit if I tap them in place but it would also fit so well that itīs kind of impossible do take the differential out.


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