SWAP OEM 3.07 DIFFERENTIAL
for
3.64 with a Quaife ATB


This is for Crossfire SRT6. The Limited or Base may be different.

Acquire a differential from 2008 ~ 2009 Chrysler 300 Touring. It will have a 3.5 L V6 and a four speed transmission. There are other Mopar cars with this set up, but these should work. Mopar part number is 52111503 AF or AH. The crown gear in both the Crossfire SRT6 and the Mopar differential are the same at 190 mm in diameter so they easily unbolt and swap over to the new differential. The axle splins are the same on both the Chrysler 300 and the Crossfire, 27 inboard 25 outboard, so again everything will slip together.

I spent a lot of time (wasted) looking for just the SRT flange as it is larger than the one that comes with the Mopar which is the same smaller size as on the Limited. So if you want to keep your original differential together, the easiest, fastest way to go is simple purchase a SRT6 differential from a junkyard. This solves a couple problems. Take the crown gear and pinion from the Mopar differential and place them in the SRT6 case.

You will need new seals for the axles and the pinion, a new crush spacer for the pinion and locking nut for the flange:

Axle seal National 711054
Pinion seal National 711055
crush spacer Mopar# 52111442AB
flange nut Mopar# 5174162AA

Unfortunately, Mopar thrush washers are no longer available. You can try Mercedes. I used the ones that were in the case and proceeded. I bought new bearings and race for the pinion and used the same axle bearings and race that where in the case. Some shims for the pinion can be bought new, but again I used the ones that came with the used differential. More than likely you will need to adjust the backlash with the new setup between crown and pinion. This is done by changing large snap rings/shims at the axles. These snap rings move the crown gear inward to tighten the mesh and reduce backlash. Some of these can be bought new, but many of the most used sizes are discontinued. I did sand/hone a thick snap ring down to the proper size to get the back lash correct.

Some part numbers for the snap rings/shims:

Mopar # 52111696AB for a 4.30 mm thickness
Mopar # 52111705AB for a 4.45 mm thickness
Mopar # 52111671AB for a 3.80 mm thickness
Mercedes # A 2109940341 is the same 3.80 mm thickness

While I was at this I also installed a Quaife ATB limited slip differential. Unlike a WaveTrack, these are available brand new out of Great Britain. I bought from ebay as I had problems making payment directly to Quaife, Model QDF30B. You will need to grind a small amount away from the case wall, maybe 1/16 inch max to get the Quaife into the case. Crown gear bolts right on, axles slip right in, no problems.

This is a good time to upgrade and or re-enforce the rear sway bar if you are so inclined. By loosening the entire rear carrier frame it will drop down giving you enough room to slide the old out and in with a new sway bar. I put H & R in the front and rear and she rides much more solid while turning. I also strengthened the rear attachment points at the cars frame. I wrote and pictured that in post 21 of thread “Mystery Trump somewhere in the rear of my SRT6”

I sent the TCU and PTCM to Mercedes Swap Shop for proper tuning. I have had it together now just a few days and trying to keep it mellow for 500 miles when I will change the oil and be ready to run. I have checked the temperature after running 80 mph (that’s about 3100 RPM) for about ten miles at 176F. All other temperatures have been lower and I hear no whining or clunking sounds so all seems well. The Swap Shop did really quick work. The transmission now has four modes and when I use “Agility” I must turn the traction control off, because evening when not intending with traction control on the car will start the bucking horse routine with the brakes clamping down as wheels start to spin.

I’m guessing top speed now is about 155+ similar to a Limited, but I do not run much at 180 mph. The guys pulling over to the next lane at a red light are plentiful.

Running about 75 mph with cruise control on the Freeways gives about 20.5 miles per gallon of gas.

 

This is the same as the pdf above
Specific directions when changing differential

This is for SRT6.

Limited, Base may be a little bit different.

If I where to do this again I would disconnect the flex disc at the differential flange, remove the rear exhaust pipes and muffler, disconnect the parking brake cables and then drop the entire carrier frame. It is only four bolts and then with it on the floor or work bench you have easy access to everything. I used the method below as it has been done by other forum members.

What I did do was disconnect the flex disc, drop the rear exhaust, disconnect the parking brake cables and passenger wheel linkage, only the lower control arm remained connected, drop the differential down, pull the passenger axle shaft out from differential and then remove the differential by pulling the driver side axle out. All the driver side links remained untouched. Fortunately I have a lift so I can get under the car. I wouldn’t attempt without a lift. As you work either put the bolt back in the hole it came out of, once the item has been detached, or label a zip lock bag and place the bolt in it so you will know where they will return when assembling.

Take off the wheels, put the car in neutral (if your are tuning the TCU & PTCM disconnect the battery and get them in the mail). Lift the car. Drain the oil out of differential.

Remove the brake caliper from the rotor and tie it up out of the way. I also removed the black plastic cover from the fuel pump and filter.

Remove the rear exhaust. My resonator had been removed years ago, but it is still long and with the bend it is awkward to deal with the weight. I strapped the muffler to the transmission jack and placed a roll away tool chest with a 6x6 piece of lumber under the end near the piping joints. I have a T handled hook about 13 inches long that I used to pull the two rubber connectors down and off the muffler. You have to have the entire piping fairly level to get the slip joint connection to pull apart. The donut style connection is much easier to deal with. Your piping may be different than mine. I know the Limited has a single pipe aft from the connection, but my SRT6 has two.

The lateral link (toe adjustment), trailing link, and track link I disconnected from the cars frame. They come apart a lot easier than going back together as the bolt is a very tight fit through the hole in the frame and the hole in the links bushing. The camber link I disconnected at the hub, and the sway bar link and shock absorber get disconnected at the lower control arm. The camber bolt is easy to strip at the head. Be certain your torx bit is completely inserted into the bolt head. I used a spring compressor to safely take tension off the coil spring while disconnecting the shock absorber and the sway bar link.

Loosen the bolts holding the flex disc to the differential. The pinion shaft of the differential protrudes about ½ inch into the flex disc so you must force the drive shaft forward to get the differential down. You will get 3/8 inch of free play by loosening the center bearing support bracket. The center bearing can then move forward making this easier. Notice the nuts on the flex disc are all on the rear. They do not alternate as in some setups.

The differential is heavy. You will need something to get under it and hold it for you. I have a transmission jack so I attached it to the jack before loosening the forward bolt and the two rear. Be advised there are steel washers and a rubber bumper/washer between the differential case and the cars frame at the forward bolt. Look at how they sit in relationship to one another.

When you get the differential down move the drive shaft to the side and disconnect the parking brake cables from the tensioner in the drive shaft tunnel. This may not be necessary, but they stretch tight when removing the axles and I did not want to take a chance in damaging them, so better safe than sorry.

When you get the differential down, you move it forward stretching both axles which are still attached. Twisting the differential and jerking it toward the driver side should get the passenger side axle out. Pulling and jerking toward the passenger side should remove the driver side axle. My passenger side came out relatively easy, but driver side got hung up. I spent three hours pulling jerking spraying penetrating oil on it but it would only come out about 1.25 inch. It was not hung up from the clip/ring. That had passed out. Something else had it stuck. I tried rotating the axle using a pipe wrench to reorientate the shaft to the differential but to no avail. Generally pissed off with the day, because that damn thing would not slide apart I went to bed for the night. Next morning I gave it a couple tugs and it came apart. Go figure. I did notice the axle shaft outboard from the splines had some scaring so before reassembly I polished both axle shafts with emery cloth.

Putting the new differential in was more difficult than the removal process. First I slipped the drivers side axle in, not too bad, but getting enough room to place the passenger side axle in the hole without scaring the new rubber seal was a strain. I finally got it in and I have no leaks, but it isn’t an easy lift it up there slip it in operation. I used the transmission jack to hold the differential while inserting the axles.

Reconnect the parking brake cables if you took them off the tensioner.

Now tilt the differential up in the front force the drive shaft forward and get it started by inserting the pinion shaft into the center hole in the drive shaft disc. You must also have the disc lined up so the bolt holes will match up correctly or the flange will prevent you from slipping the differential into place. This is why the car is in neutral so you can spin the drive shaft and get the bolt holes lined up.

Okay, that’s the easy part now you get to reconnect all the links and the coil spring. Fortunately pulling the lower control arm down gives enough clearance to put the spring back to it’s proper place without the use of the spring compressor. Line up the bottom of the spring with it’s indent in the lower control arm; the rubber perch sets where it fits at the end of the spring on the top. I put the track bar back together first then the camber, the lateral (toe adjustment) and finally the trailing link. Get the links up into their place before inserting the first bolt. If you start reconnecting without having the links into the frame you may find that you won’t have the room to move them into position. It went pretty good though lining up the track link and getting the bolt all the way through the hole had me talking to myself again. The trailing link had me talking to god, and the engineers. The service manual tells us to break the hub from the axle to get all this apart and connected again. Might be best to follow sage advice, but at this point I plowed onward. I did get the trailing link reattached to the carrier frame by inserting two lugs into the hub. Using one as a place to put a small bottle jack which was sitting on a 2 x 8 plank on top a trusty roll away tool chest, and the other lug to lever the hub forward and up to a position the trailing link could be reattached. That’s the trick. Use the lug with a 17mm socket and a breaker bar oriented so that the bar doesn’t flex at the head, but you use it as a solid lever forcing the hub forward and up so that the bolt can be run through the bushing.

Okay, now you get to connect the sway bar link and the shock absorber. Not too bad as I could raise the lower control arm up by using a high floor standing screw jack, insert the bolt and tighten it up.

Everything is hooked back up, but the toe is certainly way off. This job just doesn’t want to end. So about two hours later after using toe boards and a long straight edge I get the rear toe pointed in the right direction.

Now, reconnect exhaust piping.

If you got this far be advised I did all this with just my own two hands. Thankfully I have a well stocked garage and some experience. This is not a job to jump into without a bunch of tools, and some fortitude. It would help a lot to have an extra pair of hands with some muscle when lifting and twisting. Good Luck!

 

I wish U had contacted me first, i could save you a lot of time and parts, you see the V6 charger has a 3.64 diff
AND it firs right into the crossfire both limited and srt6 It ia a bolt in ,,,
both use the same housing, ok you need a shorter bolt for the front bolt, the one that goes up
as for the yoke you can use the rear 1/2 of a limited driveshaft, (the drive shaft is "0" balanced )
Here is what i ran with each rear, stock srt6, the 307 in 1/4 mile ran 13.3
yet the 327 (no other change ) ran 13.1, now i installed the 3.64 it ran 13.5, yep slowed down ,, that was the best of 5 to 7 runs with each rear the 3.45 ran 13.0 stock and 12.008 modified I like the 3.45 the best ,,HI way and city driving.
the best rear i found is the 3.45,,, incase you want a 307, or 3.27, or 3.45, or 3.64, or 3.91, i have all of them most with
the tcu to go with it. the 3.91 is $1500 and the 3.64 is $1000, the 3.64 , i do not have a tcu for the 3.64
and i can remove and reinstall the rear in one hour I can tell u how to do that,,,, . jim

note; they say a Quaife fits this housing which means it also fits the crossfire

 

The shorter front mount bolt is 60 mm vice the Crossfire at 110mm long; Mopar bolt part 6102382AA. I doubt you can run the Charger differential without also changing the cover, as the Mopar Charger cover is considerable deeper in depth (about 5/8”). You can’t get the front mounting bolt to match the car frame without swapping the cover. To run the MOPAR differential case with 3.64 gears you need to change the cover, the front mount bolt and match the flange to the Crossfire either by placing a large flange on to the Mopar differential ( preferred) or switch the rear half of the SRT6 drive shaft to a Limited.

Considering this swap on the SRT6 the preferred method would be using an SRT6 differential and putting the Mopar 3.64 gear set into the SRT6 case. You get the correct flange, and the mounting points front and rear are the same.

If you are going on to a Limited or Base using the MOPAR case/differential makes sense as the flange would match up, but you still need to swap the MOPAR cover and use the Crossfire cover so the front mount bolt and hole lineup. You would also then use the shorter 60 mm front mount bolt.

 

I have a 3.91 installed into a 6 speed limited, in Calf installed in 2015 ,, some of the 05 charger's diff has the same rear cover as the crossfire (mid year change i guess) because some did not ,and i machined the bolt hump/boss by 3/8" ( that is by memory ) i also have a 3.91 installed into a srt6 in Ft Lauderdale. I have a 3.64 from a 06 charger installed in a srt6 in Wisconsin . I have 3 srt6's and 2 limited with the 3.45 all with little to no modification ,, oh I also have a srt6 with a 2.86 installed all of these the owner can keep their original rear end because all were a bolt in turn key setup. yes the auto cars we did the TCU either a new one or reprogram their tcu Just trying to help you but looks like you have it under control. if u would like to know how to change the rear in under two hours let me know?
oh also i changed my first rear from the 307 to the limited 327 in 2011 .
the above had the srt6 yoke for the srt6 ca,r except 2 which we used the rear 1/2 of a limited drive shaft all the limited cars we did not have to change the yoke as the late o5 and o6--V6 challenger had the limited yoke,, note the V8 challengers had a different yoke.