Factory Five Racing Forum banner
1 - 15 of 15 Posts

·
Premium Member
Joined
·
1,604 Posts
Discussion Starter · #1 ·
Hey, Guys. 8.8 IRS rear end. I've heard that it's best left to pros, but what if you wanted to learn and do it yourself, how hard can it be after building the entire car?

What average mechanic has done it and had good results? Does anybody have a good playbook or link to some good instructions? What "complete kit" should I get? I'm changing from 3.27 to 3.73, I've decided on this so I don't want the choice of gears to be a debate.

Any thoughts appreciated.

All the best, Don
 

·
Registered
Joined
·
3,676 Posts
Don,
I hope you get some good input. I have not done any rear gears. My reading of the rear end and experience with gears a long time ago.. turbine reduction gears.. is that there is feel and experience in gettting the lash right. If you don't mind the noise you can get by with close, otherwise you take it out and shim again..

Yes you can do it. It just might take a couple of tries to get the experience level.

 

·
Charter Member
Joined
·
4,001 Posts
Don:
Google "Bad Shoe Productions"
They produce a DVD on changing gears in an 8.8, both IRS and solid axle.
The narrative is excellent and the mechanic has 20+ years doing just Ford gears.
Go for it ,you'll be very pleased with the results.
Paul M.
 

·
Senior Charter Member
Joined
·
2,424 Posts
I've been working on mine all weekend. The best instructions I found was on an online mag I subscribe to called "FordMuscle". The Chiltons manual does not cover it and the 1 page sheet that came with the gears had about 20 steps, starting with "Jack the car up" and then it said..."If you have a Ford Differential, reverse the order." ORDER OF WHICH STEPS!!!!

You will need a hydraulic press for the pinion bearings. I have my gears set up where I want them but ran into a problem with not being able to obtain sufficient preload on the pinion shaft bearings. In my particular case, this project has been very frustrating and I have rebuilt around 20 automatic transmissions. The hard part is you have to shim under the timken bearing behind the pinion to set gear lash and correct contact position. The bearing is a press fit. If your shims are not correct you must remove the bearing by the inner ring-not the cage and this is almost impossible. (actually, for my tools, it was impossible) This is very touchy work as you do not want to damage the bearings. I'll be posting a question regarding my preload problem so as to not hijack this thread.

Also, you will most likely want to rebuild the spider with new clutch packs so this can become pretty involved.

Jerry
 

·
Gelcoat Driving Maniac!
Joined
·
4,373 Posts
Don,

I'll second the Bad Shoe Productions video. I bought it on Paul M's advice and it's great. The guy leads you through the entire procedure and shows you exactly how to do it. The newest version (what he is currently selling) also has chapters on the 9" rear and the aluminum housing. It's $35 that you won't regret spending.

When you go to the auto parts store for gear marking compound, you can ask for "Prussian Blue", that's what the guy at NAPA kept calling it and he couldn't find it until he looked it up under that name.

Good luck.
 

·
Junior Charter Member
Joined
·
733 Posts
Don
904-509-8007 is the number to Mike Britts.
Call after 6pm He is probably the best Differential builder in the state of Florida.
More than likely if he is not busy he can have that gear changed out in about an hour. If you have the hour to spare he can show you exactly how to set the rear up.
Tell him Pete sent you.
 

·
Senior Member
Joined
·
3,798 Posts
Last year one of the Mustang magazines did an article on this, walked through the steps with photo's. It was either Mustang and Fords or Mustang Monthly.
 

·
Registered
Joined
·
1,888 Posts
I did it and it is not that hard. I used some instructions from the Mustang Corral as a guide. If you are using Ford gears the shims will likely not need any changes. The hardest part was getting the old bearings off the pinion so I could get the shim out.
David W
 

·
Charter Member
Joined
·
7,902 Posts
I have done the rebuild - its not that hard, but not particularly enjoyable. Here's the website I used for the rebuild - I read this through until I could do it in my sleep. The tools that I had to get were an inch pound torque wrench (got this cheap from a bicycle supply shop). I borrowed a 6 ton hydraulic press. Hardest part was getting the bearings off the carrier - almost impossible to use the press to get these off - quickest way is to use an angle grinder and carefully cu through them as much as you can (after removing the cage and the bearings) without cutting into the carrier - then use a chisel and whack it with a hammer and they will break free - let me know if you have any questions on that part.

Here's the website...

http://www.angelfire.com/theforce/5ohcpa/cpa5ohtech001.htm

I used the FRPP rear end rebuild kit from Max at 5 star ford - good prices. It has everything you need and you can get different ones with different degrees of completeness. I also did the alternate stacking method on my clutches. Overall I was glad I did it my self. However the pinion seal that was included has no sealant on it, and I ended up with a leak from the seal. Then I had to pull it apart to replace that. Then shortly after that my pinion bearing went out, so I had to rebuild it again. So far appears to be doing well. There is a slight whine to the gears at a certain speed, but not noticeable unless you listen for it. Overall I am glad I did them myself.
 

·
FFCobra Fanatic
Joined
·
12,975 Posts
Best advice I can give is to use FORD parts when swapping gears. The quality of the Ford gears and shims is clearly better then after market sets. You will find the shiming easyer since ford gears are machine almost exactly identical.
After market gears are hi quality,just shim amount will be similar when changeing a ford gear with a ford gear.
 

·
Charter Member
Joined
·
4,001 Posts
I also second the use of Ford gearsets.
They are much closer in tolerances than the aftermarket stuff.
Paul M.
 

·
Senior Member
Joined
·
1,913 Posts
I did it about 6 months ago, ditto most of the positive comments above.
Here's what I would do differently next time:
* New FMS gears
* paint & pattern the gears that I am replacing (baseline) before the swap
* make friends with someone with a press - I did it without a press (really), it was more of a PITA.
* I bought an extra pinion bearing, ground out the inside diameter and this made the "install, measure, shim, repeat" process much quicker
* encourage my wife to go out more.... she was NOT amused to find the new ring gear baking in her oven

Read all of the above instructions, each one offered it's own "cool trick".

CAVEAT - I haven't go-karted yet, so my rebuild might schrapnel on me yet....
 

·
Senior Member
Joined
·
2,746 Posts
Ditto also everything above. Use FORD gears and the hardest part will be the pinion bearings. I borrowed the use of a press at the local JR. college. It was a fun learning experience. I also used the guide from the Mustang Corral. Did not have to change any shims.

Have fun.

Chris.
 

·
FFCobra Fanatic
Joined
·
12,975 Posts
Save the old pinion bearing. Use a dremmel tool to sand out the inside so it's a slip fit on and off the pinion gear. This lets you try different shim thickness's with out needing to press the bearing on and off.
Save old crush sleeve also. Use it to check and set gear tooth pattern as it can be removed and installed without worry of damaging the new sleeve.
Find a regular nut the same threads as the locking pinion nut. It will allow you to tighten the old crush sleeve to remove all slop so pattern can be checked and changed if needed.
Use the minimum back lash setting of .008-.009".
With the position of the drivers seat and how close it is to the rear housing. The larger back lash settings will make for a noticable noise from the rear.
Almost forgot. Keep a few of the old ring gear bolts. Cut off the heads and round over the ends making them studs. Put 4 of these studs in the ring gear to help align the bolt holes as you press on the new gear to the spool. pressing on the gear is a one shot deal. miss the bolt holes and needs to be removed and reinstalled. studs help here.
 
1 - 15 of 15 Posts
Top