Okay, over Christmas break I am going to be changing out my gears...

Long story short, I rebuilt my 3.27 9 bolt and it worked PERFECT until and bolt backed out and chipped my gears. Now I need new gears...

Well, I bought a 3.45 Posi with carrier and everything (side spacers) that needs a rebuild.

I dont know how to space the gears, but if I change it all out and put the gears on my rebuilt carrier, and use the side spacers from the 3.45 posi carrier I got should I be okay?

I am hoping it will be close and not whine or anything. Who thinks it will work?

 

I have a used set of gears in my 9 bolt and have put many used sets in over the years. If the pinion bearing is in place with the shims, and you have the carrier (posi) with the bearings and shims that were in the housing it came out of, it should work. Drop in the pinion and set the preload. Put the carrier and shims in and torque the caps and check the clearance. Getting the carrier/races/shims into place is tricky. Everything must be lined up real straight to slide in. You may have to tap the assmy in with a mallet. Just don't beat it in. If it binds up it isn't lined up right. If the clearance is high/low swap the shims around to get the correct end play. Just make sure you keep the same TOTAL shim height that was on the carrier to maintain the carrier preload. If any of this doesn't make sense do a lot of research or have someone with setup exp drop it in. It's really straight forward once you do it. I have had near 100% success using this method.

 

When moving parts from one housing to another it ususally doesn't work out to be the same. The manufacturers have tolerances on all of the machine work, so most of the time the shims from one rear end are not correct for another. Sometimes you get lucky and they are close enough to run without making noise, bit it is best to set everything up as if it was all new. The pinion depth, bearing preload and backlash all need to be checked and set right. I recommend getting an installation kit for the 9 bolt and install the new bearings. Use the shims to set everything up correctly.

Checking backlash on the ring gear with a dial indicator.

Checking pinion bearing preload.

 

Big gear head is right. It is always best to set up a gear set from scratch.

However, my experiance has been very successfull using the original factory spacers. Not trying to start a debate just letting you know that there are differing opinions. I have found that the differance among housings isn't enough that it matters when all is said and done- most of the time. Currently running sub 8-second 1/8 mile times with a daily driver and it's smooth and quiet with take out bearings and shims. Of course, yours may be that 1 in 100 it doesn't work out. lol

 

Okay, Thanks. I am going to try and use the spacers first, if not, I guess I am going to have to go from scratch. Thanks!

 

Im actually going to attempt to rebuild my 9 bolt over winter break as well. Has anyone made a step by step how to for reshiming the posi? My gears looked good the last time i had the cover off so i dont think they will pose any problems. Also if im going to do all this I think i should replace my pinion bearing/seal and axle bears/seals. Am i right in thinking that?

 

bump for the above question.

 

Yes, there is an excellent step by step with pictures. Sorry don't have the time to find it right now. There is one in the "tech" section and it's quite good also. Do a web search on "rebuild 9 bolt posi cone" and variations of that and you should find it. It's worth the search...

 

I can help... Ive done this already. Here is what I used.

https://www.thirdgen.org/9boltservice

 

Here's the link on the web with pics;

http://mpikas.blogspot.com/2008/03/r...rner-cone.html

Basicaly the same info.