Gear install question..

**Lunatikgixxer** · 01-09-2012, 07:27 PM

Ive never really cleared this up with myself but on the stock 10 bolt is it possible to install a new set of gears as a DIY job? I see most of the sites carry installation kits for replacing the gears. But ive heard you cant change them yourself, and that you need to get them machined in. If its a DIY job id love to get me new gears...

**35th-ANV-SS** · 01-09-2012, 07:44 PM

They can be installed yourself. However, you need to know how to properly set the pinion depth, pinion bearing pre-load, and check the backlash. Once all that is done you check the tooth contact pattern. I've never personally done it, but there are a few on here who have many times.

There is a step-by-step procedure on a few online sites that sell gears. I've read them before just for my own curiosity.

Like anything else, if you are mechanically inclined and have the proper tools and good instructions, it can be done.

The bad: if you mess up and run the gears installed wrong it doesn't take long for the wear pattern to set it. Once that happens, you basically have a set of junk gears.

**Lunatikgixxer** · 01-09-2012, 08:03 PM

Where is a write up? Id like to read it and know what tools youll need to have. Id consider doing it myself but id like to do it correctly of course lol. I dont have a clue on how to set the pinion depth, bearing pre-load, or the backlash..

**35th-ANV-SS** · 01-09-2012, 08:13 PM

There is a Sticky

http://www.ls1.com/forums/f8/how-tos...-related-5507/

**Lunatikgixxer** · 01-09-2012, 08:42 PM

Sweet nice write up. I kind of skimmed through it but i got the idea. Do our diffs have the paddle it is talking about? Do you have any idea if that write up covers EVERY step?

**35th-ANV-SS** · 01-09-2012, 08:48 PM

I never looked through that particular write-up to be honest, just read other one's online.

I just seen it was part of the LS1 community so I decided to keep the information in the family instead of posting an outside link.

I never really researched it in depth as I went with a 9"

**Lunatikgixxer** · 01-09-2012, 08:55 PM

oh ok got cha. Yeah i wish i had the cash for a new rear end id definitely get the 9 inch. Thanks for the link though!

**35th-ANV-SS** · 01-09-2012, 09:19 PM

FBJ or someone else who has changed them first hand will pop in.

**Firebirdjones** · 01-10-2012, 07:15 AM

35th covered it. I haven't read the writeup but I'm sure it's giving you an idea of the labor involved.
You'll need a pinion depth gauge, and a dial indicator with a magnetic base, as well as a small needle style inch pound torque wrench to check pinion bearing preload.
I check the pattern after all that is set, just as 35th mentioned. Sort of double checking the work. A setup kit will come with gear marking compound, and usually a piece of paper that shows what a correct gear pattern looks like and what a bad pattern looks like, as well as what needs to be changed for different looking patterns to obtain the correct pattern. If not it's in all the assembly manuals. But if everything else was done correctly as per gear manufacture recommended settings, (ie: pinion depth, back lash) the pattern should be spot on.

I'll say there are 2 somewhat time consuming issues when it comes to the GM rearends. First is setting pinion depth. It will have to come out a few times to get it right. The problem is the shims, they are behind the pressed on pinion bearing. A trick I like to do is take a used bearing, and hone the inside so it slips on and off by hand, rather than pressing it on and off and risking ruining the new bearing. I prefer to press the new bearing on the final assembly after I've set pinion depth with a used bearing.
The other time consuming issue is backlash while setting proper preload on the carrier bearings. Backlash can range from .006 to .009 but at the same time you need preload on the carrier bearings and that is accomplished with packing in shims. The old GM books tell you after backlash is set and things are snug, to install another .004 of shims on each side for bearing preload. That's hard to do as they are paper thin, and need to be sandwiched in between thicker shims or they get detroyed. It's also tricky because it tends to change your backlash setting. So you might find you'll have to stick maybe .006 on one side, .004 on the other, or completely rethink the shim packs all together. It's just trial and error.
Some nice setup kit's will come with a side bearing shim package that encases the shims. So you can pull out the entire pack, open it up and install the shims needed and reinstall easily without fear of damaging the really thin shims. I believe Randy's Ring and Pinion still sells these.
This is one area where a 9" ford has a huge advantage in setup. They don't use side shims, they are threaded on the sides so you set preload and backlash simply by turning a locking threaded washer. Very very simple.
Hope this helps.

**Knight** · 01-10-2012, 08:13 AM

I changed mine multiple times when I had my 10 bolt......mainly because I had to due to broken gear teeth. I agree with everything FBJ stated. It's time consuming, and can get frustrating.

If you do decide to change gears, I'd also recommend a good inspection of the carrier, bearings, ect.. Everything will be apart anyway.

**Lunatikgixxer** · 01-10-2012, 11:57 AM

Ok thanks guys this seems kind of out of my league since i have not one idea in my mind on what to do until i have it apart. And i do not want to do it that way in case i cant put it back together lol.