Lots of posts asking about this including from me. Being I just completed one I am posting my experience. Its my first one and I did it alone. My experience level is I have been pulling wrenches since the 1970's.
I just completed a 6.0 psi supercharger kit and find I was no longer happy with the 2.65 gears. The R/T is one of two daily driver vehicles I own and don't want a radical gear. In the end the 3.06 is a nice little enhancement allowing the car to stay in the power better going through the gears. Its too soon to talk about the MPG difference but from what I see its small and according to the foot.
The open vs locking thing, I don't street or track drag race, and avoid hard launches from a stop like the plague because tires are pricey. I will take on a street battle here and there and love the open highways. I have not had trouble with involuntarily smoking the tires or spinning it the rain. I have been practicing some 0-60 runs, a 4.6 best so far, and did grind them a little in that single process but that's over until just before purchasing the next set.
This job is best done with a helper. I am self sheltering in place, a helper from 6 feet away is not much help.
This job is even better done on a drive on lift with a separate means of raising / lowering the diff.
I did it alone on ramps at the rear and stands at the front and a transmission jack. I had a small floor jack with a block of wood to raise a rear tire off of a ramp so I could spin the tire a little to help the splines line up when putting the axles back in.
My Steps, right or wrong its how it went:
Drain the Diff, put plug back in.
Have the system at ride height. In principle you want to start the job with the system at ride height. The axles are almost level and have the least amount of movement on the splines, so the distance from the wheel to the diff is shorter here.
Remove the tunnel brace closest to the diff. I put a plate between the exhaust and the 1st tunnel brace to support it.
Drop the exhaust out of the mufflers and move em out of the way.
Now is the time to see what you have to brace the drive shaft at the first tunnel brace. I found a 2x4 block and 1x1" square tubing sections were just right.
Try and use two pieces, you may need to remove one later to allow for some vertical movement to work the Diff Yoke Pin in/out and around the center pin bore of the coupler/shaft.
Remove the D-Shaft coupler bolts from the coupler-to-diff yoke. Leave the coupler on the D-Shaft.
See Pictured - Also Note The Seal Shields on the axles. These bend easily and will pop out easily. They can be gently tapped back on. Avoid disturbing them.
![292621]( "292621")
I'm sorry I did not get pics of this next step but will try and describe it.
The D-Shaft can compress on an internal spring an inch or so forward. You will find this space a luxury. I found a way to do this with a pry-bar without touching the rubber coupler. (You "Do Not" want to put any kind of undue forces on this coupler. None. I only contacted the the bolt ends).
I got creative making a small choker or loop out of 1/16" coated wire cable (a large ty-wrap will work) looping it through the forward D-Shaft metal yoke and putting a small ratcheting strap from it to the 1st tunnel brace.
I Did Not use the strap to jack the D-Shaft into the compressed state. I gently pried it back and then tightened the strap. I did not have the choker pulling on any part of the coupler.
Take a pry bar as described in the S-Manual seen here but note they do not show the seal shields!
You will need to get something to block out the bar as an fulcrum point to do this without mangling the shields.
There are horror stories of these being seized onto the splines at either end, Diff or at the Wheel, requiring a whole new can-o-worms (possible cradle drop or wheel & Hub removal.)
So if you have high mileage in the northern winters, and have never changed the diff oil its possible.
If I ever do another one this will be the first step just to make sure they move.
Mine spooked me at first but did move. You just pop them out about 1/4 to 1/2". Some report fits that when the bar is removed they slide in, that's ok. Just make sure they will move.
![292622]( "292622")
![292636]( "292636")
The Removal
Support the Diff with your jack and remove the forward Diff mounting bolt. The other half of the mounts is inside the cross member and if it spins you will need to pop off a cap at the top of the cross member and get a socket on it. I was lucky.
Pictured are the mount as positioned with the access cap.
![292623]( "292623")
![292629]( "292629")
Now the fun part of the rear Diff Rear mounting bolts. The heads are 21mm.
With the front bolt out as you loosen these you will want the diff to walk forward or the bolts will move out rearward and bind you into the spare tire tub.
These bolts are tight to the tune of 164ft lbs. You can work a 1/2" drive short socket and breaker bar onto them and move them. Work it off and back on, repeat.
![292624]( "292624")
To make it easier get your hands on a 3/8" drive 21mm socket and Harbor Freight Pittsburgh Socket Caps and a 9/16" ratcheting wrench.
![292625]( "292625")
![292626]( "292626")
![292627]( "292627")
After the bolts are free the Scenario is to lower the diff which increases the distance between it and the wheels allowing more room for the axles to exit the Diff.
You will push it to one side compressing the axle in all the way in while pulling the other side out.
You have to lower it quite a it, and this is one place I wish I had a helper, one of us to push and hold the Diff over, and the other to compress the other axle enough to pull it out.
Just lower it a little at a time looking at everything. I will tell you it has to come down quite a bit.
Easier said that done especially alone because you need to make sure they clear the A-Arms, don't pinch the boots wrong, the shields don't get banged up.
The install
Put new Seals into the new Diff. Take care during the rest of the process not to damage them. Keep an eye on these area at all times during the install.
Getting the splines to line up and slip into the Diff on the splines was a real learning curve. I'll skip my blunders. Remember this is my 1st time and I was alone.
While lowered push the Diff over and get one of the axles into the Diff sliding onto the non-splined portion and if you are lucky and it slips onto the splines while lowered, stop, pull the diff over onto the rest of it, celebrate, get some water.
For me it stopped at the splines, the tire is fixed on the Ramps, turning the Diff Yoke spins the other side..... heh!.
I was trying to get the 1st one on while lowered.
Only until after slipping it partially in, and then raising the Diff to near level, twisting and palm bumping did it go into the splines. I took a break and repeated for the other side.
But to do the other side you have to lower it again holding it over to keep it fully onto the other axle until you can get the 2nd axle started. Again you may get lucky but I had to raise the Diff way back up, then use another floor jack to take the weight off the wheel on that side and spin it a little at the Diff Yoke, and with a palm bump she went in. I celebrated with Lunch!
All the while on the Above making sure as you work up and down and side to side working the Diff Yoke Center Pin around the Rubber D-Shaft Coupling. Even compressed forward its close.
Bolting it In
OK, now you are lining it up to have the rear bolt holes line up, and the tip of the Diff Yoke Pin into the drive shaft. This will have the front mount touching the cross member mount not so hard you cannot wiggle the diff.
Other than the space between the Spare Tire Tub another Horror to beware of is starting the already almost impossible to access cross member mounting bolts.
You MUST make sure you are not going to cross thread these. Its going into Aluminum which practically invites a bad start, you only get one shot. If you screw up its all gotta come back out.
To avoid this while the Diff is on the bench I chased the threads with a M14-1.5 Tap. The bolts were in good shape. I was able to start and run them in with the two finger dance 95% of the way in while micro-adjusting the Diff and the trans-jack to get that perfect line up. Your odds of cross threading increase greatly if you use a tool to start the threads. Finger them in at least several turns.
Start your front bolt, Torque the rears a little and then the front, and then lock down the rears finishing with the front.
Fill the new box while the exhaust is not in the way and button the rest up.
No leaks, noises, or vibration. Not a night and day difference but complements the blower, she stays "In It" much better between gears. I was afraid the change would be more than I wanted but its not. The 2.65 gears were sort of an insult to the blower.
![292628]( "292628")
I just completed a 6.0 psi supercharger kit and find I was no longer happy with the 2.65 gears. The R/T is one of two daily driver vehicles I own and don't want a radical gear. In the end the 3.06 is a nice little enhancement allowing the car to stay in the power better going through the gears. Its too soon to talk about the MPG difference but from what I see its small and according to the foot.
The open vs locking thing, I don't street or track drag race, and avoid hard launches from a stop like the plague because tires are pricey. I will take on a street battle here and there and love the open highways. I have not had trouble with involuntarily smoking the tires or spinning it the rain. I have been practicing some 0-60 runs, a 4.6 best so far, and did grind them a little in that single process but that's over until just before purchasing the next set.
This job is best done with a helper. I am self sheltering in place, a helper from 6 feet away is not much help.
This job is even better done on a drive on lift with a separate means of raising / lowering the diff.
I did it alone on ramps at the rear and stands at the front and a transmission jack. I had a small floor jack with a block of wood to raise a rear tire off of a ramp so I could spin the tire a little to help the splines line up when putting the axles back in.
My Steps, right or wrong its how it went:
Drain the Diff, put plug back in.
Have the system at ride height. In principle you want to start the job with the system at ride height. The axles are almost level and have the least amount of movement on the splines, so the distance from the wheel to the diff is shorter here.
Remove the tunnel brace closest to the diff. I put a plate between the exhaust and the 1st tunnel brace to support it.
Drop the exhaust out of the mufflers and move em out of the way.
Now is the time to see what you have to brace the drive shaft at the first tunnel brace. I found a 2x4 block and 1x1" square tubing sections were just right.
Try and use two pieces, you may need to remove one later to allow for some vertical movement to work the Diff Yoke Pin in/out and around the center pin bore of the coupler/shaft.
Remove the D-Shaft coupler bolts from the coupler-to-diff yoke. Leave the coupler on the D-Shaft.
See Pictured - Also Note The Seal Shields on the axles. These bend easily and will pop out easily. They can be gently tapped back on. Avoid disturbing them.
I'm sorry I did not get pics of this next step but will try and describe it.
The D-Shaft can compress on an internal spring an inch or so forward. You will find this space a luxury. I found a way to do this with a pry-bar without touching the rubber coupler. (You "Do Not" want to put any kind of undue forces on this coupler. None. I only contacted the the bolt ends).
I got creative making a small choker or loop out of 1/16" coated wire cable (a large ty-wrap will work) looping it through the forward D-Shaft metal yoke and putting a small ratcheting strap from it to the 1st tunnel brace.
I Did Not use the strap to jack the D-Shaft into the compressed state. I gently pried it back and then tightened the strap. I did not have the choker pulling on any part of the coupler.
Take a pry bar as described in the S-Manual seen here but note they do not show the seal shields!
You will need to get something to block out the bar as an fulcrum point to do this without mangling the shields.
There are horror stories of these being seized onto the splines at either end, Diff or at the Wheel, requiring a whole new can-o-worms (possible cradle drop or wheel & Hub removal.)
So if you have high mileage in the northern winters, and have never changed the diff oil its possible.
If I ever do another one this will be the first step just to make sure they move.
Mine spooked me at first but did move. You just pop them out about 1/4 to 1/2". Some report fits that when the bar is removed they slide in, that's ok. Just make sure they will move.
The Removal
Support the Diff with your jack and remove the forward Diff mounting bolt. The other half of the mounts is inside the cross member and if it spins you will need to pop off a cap at the top of the cross member and get a socket on it. I was lucky.
Pictured are the mount as positioned with the access cap.
Now the fun part of the rear Diff Rear mounting bolts. The heads are 21mm.
With the front bolt out as you loosen these you will want the diff to walk forward or the bolts will move out rearward and bind you into the spare tire tub.
These bolts are tight to the tune of 164ft lbs. You can work a 1/2" drive short socket and breaker bar onto them and move them. Work it off and back on, repeat.
To make it easier get your hands on a 3/8" drive 21mm socket and Harbor Freight Pittsburgh Socket Caps and a 9/16" ratcheting wrench.
After the bolts are free the Scenario is to lower the diff which increases the distance between it and the wheels allowing more room for the axles to exit the Diff.
You will push it to one side compressing the axle in all the way in while pulling the other side out.
You have to lower it quite a it, and this is one place I wish I had a helper, one of us to push and hold the Diff over, and the other to compress the other axle enough to pull it out.
Just lower it a little at a time looking at everything. I will tell you it has to come down quite a bit.
Easier said that done especially alone because you need to make sure they clear the A-Arms, don't pinch the boots wrong, the shields don't get banged up.
The install
Put new Seals into the new Diff. Take care during the rest of the process not to damage them. Keep an eye on these area at all times during the install.
Getting the splines to line up and slip into the Diff on the splines was a real learning curve. I'll skip my blunders. Remember this is my 1st time and I was alone.
While lowered push the Diff over and get one of the axles into the Diff sliding onto the non-splined portion and if you are lucky and it slips onto the splines while lowered, stop, pull the diff over onto the rest of it, celebrate, get some water.
For me it stopped at the splines, the tire is fixed on the Ramps, turning the Diff Yoke spins the other side..... heh!.
I was trying to get the 1st one on while lowered.
Only until after slipping it partially in, and then raising the Diff to near level, twisting and palm bumping did it go into the splines. I took a break and repeated for the other side.
But to do the other side you have to lower it again holding it over to keep it fully onto the other axle until you can get the 2nd axle started. Again you may get lucky but I had to raise the Diff way back up, then use another floor jack to take the weight off the wheel on that side and spin it a little at the Diff Yoke, and with a palm bump she went in. I celebrated with Lunch!
All the while on the Above making sure as you work up and down and side to side working the Diff Yoke Center Pin around the Rubber D-Shaft Coupling. Even compressed forward its close.
Bolting it In
OK, now you are lining it up to have the rear bolt holes line up, and the tip of the Diff Yoke Pin into the drive shaft. This will have the front mount touching the cross member mount not so hard you cannot wiggle the diff.
Other than the space between the Spare Tire Tub another Horror to beware of is starting the already almost impossible to access cross member mounting bolts.
You MUST make sure you are not going to cross thread these. Its going into Aluminum which practically invites a bad start, you only get one shot. If you screw up its all gotta come back out.
To avoid this while the Diff is on the bench I chased the threads with a M14-1.5 Tap. The bolts were in good shape. I was able to start and run them in with the two finger dance 95% of the way in while micro-adjusting the Diff and the trans-jack to get that perfect line up. Your odds of cross threading increase greatly if you use a tool to start the threads. Finger them in at least several turns.
Start your front bolt, Torque the rears a little and then the front, and then lock down the rears finishing with the front.
Fill the new box while the exhaust is not in the way and button the rest up.
No leaks, noises, or vibration. Not a night and day difference but complements the blower, she stays "In It" much better between gears. I was afraid the change would be more than I wanted but its not. The 2.65 gears were sort of an insult to the blower.
