Complete Rear bushing and 3.91 gear swap DIY
Here is my rear bushings and 3.91 gear swap build thread. I'm focusing on road racing track preperation but most of these mods will be applicable to all gen 5 camaro owner.
I built a simple tool that worked for the majority of the trailing, toe and control arm bushings. I only had 2" square tube lying around but it worked really well.
Here you can see just how well the square tube works
For the trailing and toe rods I removed one side of the rubber bushing lip to make it easier to press out. I also used a little heat from a map gas torch to soften things up as I applied some pressure.
Here is one finished compared to the factory unit
On the hub side the square tube also worked well
Last year I installed the pedders allignment bolts front and rear. In the rear I didn't need the full range of adjustment so I didn't open the slot. While I had the subframe out of the car I took the opportunity to open the adjustment slot. I used a long shaft burr. Total job only took 10 minutes.
Now on to the subframe bushings. I started with the rear bushings by removing the fiberglass tab on the bottom of the bushing so the cup could sit flush.
I also cut the rubber tabs so the the press pipe could sit flush on top
Here you can see I used a 4" PVC coupler and some 1/2 inch threaded rod. I used my earlier tool as a back plate and the steel cup that is removed from the bottom of the bushing as a top plate.
I applied some heat very carefully so I didn't melt the PVC too much. I was able to use the PVC pipe for both sides which only took about 3 minutes each to setup the tool and remove the bushing (Using just hand tools)
For the front subframe bushings the bottom cup can be removed by tapping a large screw driver or pry bar from the top.
I also had to remove the tab from the front bushing sleeve
The front required a 2" threaded cap to press the bushing out from the top.
I used a cylinder hone to LIGHTLY clean and hone the bushing seat. Sandpaper could have done the same job but I think the hone was much quicker and consistent. Here is the cleaned and painted seat.
And.... The finshed bushings
Next the upper control arm bushing was pressed out by a friend at a local garage using a ball joint press.
The differential bushing are like sausage, we like how it tastes but we don't want to see how it's made. It wasn't pretty
First I started by cutting the rubber core and steel ferrule out using a 1 3/4" hole saw. I used WD-40 as a cutting lubricant which kept the blade from binding in the hot rubber.
Then I cut the steel jacket in two places using a sawsall (Careful not to cut into the housing) then punched the steel sleeve out using a steel punch and hammer
Here you can see the carnige. The diff bushings were like excerising a demon.
I did nick the housing a few times so I carefully filed down the sharp edges and used a little honing, careful not to really remove material but just make it smooth.
and here it is with the bushing in place. even with the clean-up work it only took about 10 minutes per bushing.
More to come. This week I'll be getting a pinion depth guage and showing how I setup my 3.91 gears.
Awesome write up! Subscribed and thanks! :thumbup:
I have done almost all of the bushings that you have shown here. another way to get the bushings out with out having to make the 'custom' tool out of pvc is heating the out side metal like you showed with a torch and then taking about 3-5 very firm hits on the top of the bushing to 'pop' them out. watch your toes....
Also I would definitely like to see your gear instal instructions. I am installing mine this weekend. And am also waiting for the pinion depth/backlash gauge to arrive.
thanks for the DIY!
I should get my depth/backlash gauges this evening but I'm having a hard time finding specs the only one I can confirm is 18-25 inch lbs of rotational torque for the bearing preload.
I still need torque, backlash and pinion depth specs etc. for everything else. do you have any of these specs?
Here is a pic of the finished upper control arm bushings. I hope to have most of the rear cradle assembled this evening
Torque Specs that I'll use for the re-assembly. I saved these from another post so I can't take credit for somone elses work here... but hope it helps.
Note: Although some will say it is overkill, TTY (Torque to Yield) bolts should not be reused.
torque to seat the crush washer I have seen 150-200ftlbs. I haven't read anything on depth except along the line of the pattern looked good and that they didn't feel the need to measure because of it, so non was given.
I have a good article on patterning if you are interested that talked about what adjusts to make and all that.
Also I got my parts in today! Here some teaser pics:
That is the full Richmond kit from Jegs, along with fluid twice over, and a trick flow multi use gauge kit from summit. The gears are from parts taxi a forum sponsor!
From what I have read on a few of the threads on here i won't actually be needing the instal kit. Just the pinion, crush sleeve, nut, and ring gear and fluid. Many said that they were able to use the OE shim setup because of the way its designed and that it makes it much simpilar because of it.
I will still measure for all of the different things and check the pattern but if its all checks out then I will be shipping the instal kit back.
I finished collecting all the tools. Some I may not need but wanted anyways and some that are a must have. If I reassemble and the factory shims get everything lined up then great but if I need to adjust some shims it's a lot easier with the right tools.
But I'm sure that GM assembled MY rear end with great care and precision :doh:
So here are my tools
This bearing separator/puller is from Pittsburgh tools and I picked it up for under 30 bucks. I'll used it to separate the yoke from the pinion as well as the pinion bearing.
Next is a dial indicator and magnetic base for measuring backlash
This is a universal pinion depth gauge. I may not need this but I plan on using it on some future jobs when I'll be starting from scratch without the aid of the factory shims.
One of the most important tools is this inch pound dial indicating torque wrench. This one that I picked up from summit has a memory dial and a nice case but it wasn't cheap. I paid $200 for this one.
I also picked up this assembly bag for a couple bucks that has gear marking compound and well as a brush, loctite and some sealant. It was too convenient to pass up.
Last is a 32mm deep well axel nut socket. I had a standard 32mm socket but it wasn't deep enough so I picked this one up from AutoZone for 10 bucks.
In addition you'll need standard sockets, a click type lbft torque wrench and a few other common tool which I will highlight as I walk thru the project
Jeremywes. That bearing puller kit won't work by the way.
It's not nearly big enough.
Might want to go get the bigger one before you start
I have used their(redline) friction modifier in the past with no change in gear noise from the stock setup. So I'm not really sure how much it matters. I originally bought a 5oz bottle so ill just use the other half when I get ready to refill it all
Just for clarification purposes
Redline gear oil does not need friction modifier as per the bottle. Mobile 1 does since there are no markings of it having modifier in there.
Thank you for this DIY thread! Very informative!!!
3.91 Gear swap
On to the 3.91 gear swap.
I was impressed by this little cordless impact gun. It handled 90% of the work, however I did have to use a more powerful corded impact gun for some of the heavy lifting
This puller was too small so I had to open it up with a grinder but I was able to make it work. a 3 arm puller would have worked better.
Here is a picture after the yoke is removed
Next I marked the bearing caps left and right with a small chisel
Here you can see that I have layed everything out exactly how it came out of the housing so I can ensure it goes back in the same way.
To remove the pinion I hammered it over a piece of wood so it had something to fall on.
Here is the pinion removed from the housing
Next remove the bolts that attach the ring.
NOTE: These are reverse thread bolts (lefty tighty, Righty Loosey)
Once the bolts have been removed tap the ring off, I had to gently pry to get it started. Again I used a piece of wood so it could fall safely
I placed the carrier in the freezer and the ring on a propane BBQ. They went together very easily after that. Otherwise they would need to be pressed on.
Next using the new bolts from the GM kit I attached the ring
I removed and reused the old pinion bearing using a friends press. I would have just used a new one but the car only has 3k miles on it and the local dealer didn't carry it in stock.
Now same operation for the pinion bearing.
Here you can see the old pinion, shim, bearing, crush sleeve. Make sure it goes back on the pinion the exact same way.
Here is the old crush sleeve compared to the new one
I made a little tool out of 2" PVC pipe to tap the bearing on. It didn't take much pressure to tap it on once the pinion had been in the freezer and the bearing was heated.
Next CLEAN the pinion yoke by scraping all of the white factory paste out of the splines. Grease the inner bearing and crush sleeve to make sure it doesn't bind when you begin re-assembly.
Here I am using a pry bar and two of the yoke bolts to get some leverage as I tighten the pinion nut down to crush the pinion crush sleeve. Here is where a strong impact gun will come in handy
This is the tricky part. Tighten the pinion nut until you achieve 18 - 25 inch pounds of rotational torque. Work in slow bursts and take your time because you can't un-crush if you go past the torque range of bearing preload.
Once you have the proper rotational torque pin the pinion nut by punching it into the pinion recess
Now insert the carrier into the housing keeping all of the bearing races and shims on the same sides that they came from.
Here I used a 2x4 to tap the left side shim into place.
Now install the bearing caps and torque to spec. I used 77ftlbs
NOTE: GM makes 3 different rear ends so make sure you know what you have. I am installing this into a 2012 SS with the 218mm axles
Remember to use anti-seize anytime a steel bolt goes into an aluminum housing
Here are some GM spec that a friend printed out for me
I made a steel plate so I could get the magnetic base dial indicator to attach to the housing.
Here is the zeroed dial indicator
Here the backlash is .003" GM spec is .002 - .005
Here you can see the pattern on the DRIVE side of the ring gear teeth
Here you can see the pattern on the COAST side of the ring gear teeth
Next reinstall the case cover. I used 55lbft
Remember to use anti-seize anytime a steel bolt goes into an aluminum housing
Remember the gear lube WITH a friction modifier
Here are some GM specs
Here is where you can see what rear end your car has. You can see mine is a 218mm axle
Update- I corrected the Axle ratio with a diablo tunner so now the TC is happy and speed is registering correctly. I do notice a very subtle vibration from the diff bushings but no normal person could tell the difference. I finished my initial break-in on the gears and tried a few 75% 0-60 pulls and you can really notice the torque down low.
excellent write up and great skills you got, awesome. I can only imagine the pull with those gears!
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