After taking a shellac'ing on a Wavetrac LSD (I received a unit for a Dodge Charger/HAG215, instead of one for a Crossfire), I want to explore other options. Those who might know me from other forums know that I do not shy away from blazing new trails, when necessary, and will fabricate whatever it takes to reach a goaI. I have built a number of well executed, well sorted cars for street and track use. So, what I am about to jump into here doesn't scare me a bit

I am working on a custom setup to allow the use of the Getrag 226mm rear differential, commonly found in newer Chrysler products, namely Charger/Challenger/300, with the 6.1/6.4 engines (and select 5.7's). This differential comes in a variety of ratios from the factory, but most commonly comes with a 3.06, and a clutch type limited slip differential (LSD). It is physically larger than the Crossfire's HAG190 type differential, but it has enough in common that I think it can be adapted. It will require some fabrication work. So why do this? Well, a few reasons, really. The Getrag 226mm comes with a LSD in its normal configuration. This, of course, solves a major deficiency in the Crossfire. There is wide aftermarket support for the 226, with differential upgrades, gearing and other pieces available. It is inherently stronger than the HAG190 (stock Crossfire), or the HAG198 found in the later model Chrysler V6 cars. Lastly, they are relatively cheap, and plentiful. I picked up a low mileage 3.06 Getrag 226, which uses the same ratio as the SRT-6, for $300. I see plenty of others on eBay right now for <$600.

So why not just use the HAG198 or the HAG215 found in other V6 and V8 vehicles? The HAG198 looks almost identical to the Crossfire differential. Most are 3.64 ratio, which might be desirable. The rear cover bolt pattern is identical to the Crossfire, making that bolt in. However, the HAG198's body is longer, which puts the front mounting bolt too far forward, and the pinion sticks out about 1" too far forward (driveshaft would need to be shortened). You still have axles issues (more detail below). The HAG215 has these issues, plus it never came with an LSD, although there are Wavetrac options still available for it. Later HAG215's have the same rear cover mounting bolt pattern as the Getrag 226, which then begs the question, "Why bother with the HAG 198 or 215?"

So, I am on to the Getrag 226. There is just a lot more rationale to just jump all the way to this one, and forget the "simpler" options. The rear mounting bolt pattern is a lot different than the Crossfire, but with some fabrication, there are possibilities. To make the Getrag 226mm a bolt in affair would require a lot of rework to the rear differential cover, but it is a possibility. I have an entire rear suspension setup from a SRT-6 sitting in my shop, and I think I have made up my mind to forgo the modified rear cover, and instead modify the rear cradle, instead. Doing so will make replacing the differential a complete, bolt in affair, if I ever need to replace it/upgrade it/whatever. Cradles are not apt to wear out or break, so it makes more sense to fabricate on the part that you should never need to replace.

The Crossfire uses a rear axle of 28.375" compressed length, with 25 inboard splines and 27 outboard splines. The Getrag 226 uses 30 inboard splines, and most Chrysler axles of the era are 27 outboard splines. The Getrag also uses a larger diameter shaft in the differential. Overall distance from the rear of the case (not the rear cover, the case) to the pinion flange is the same distance. The front mounting bolt is also in the same location. The Getrag 226 rear cover uses a different mounting bolt pattern, and is much thicker than the Crossfire's. The Getrag is physically larger in all other dimensions, but I do not foresee any other fitment problems from that perspective.

Getrag 226 uses a 4 bolt pinion flange, but it appears that the 3 bolt from the SRT6 should work, and if not, there are 3 bolt options from any of the 5.7 cars that will. Incidentally, the later model Charger/Challenger/300 5.7's all use the same flex disc as the SRT-6, but with a slightly different part number. I will post some comparison photos. I am guessing the major difference will be rubber durometer differences, but functionally, they are the same.

When approaching these kinds of projects (and I have done many), I always prefer to attempt to perform some parts bin engineering, before making anything custom. For this reason, I am looking for input from some of the more "Mercedes inclined" parts of our crowd to know if there are any Mercedes applications of the Getrag 226mm, and if so, if there is any corporate knowledge about the axles in those vehicles? It would be completely awesome to find a correct length axle that will fit in the Crossfire! I can easily change out rear hubs to match whatever axles can be found. While it is a nearly bolt in affair to use the Chrysler model rear hubs, they will run a 5x114.3mm wheel bolt pattern (with lug studs), while the Crossfire uses 5x120mm lug bolts. My preference at this time is to retain the stock wheel bolt pattern, and to also retain the stock wheels. Swapping to the much more common 5x/114.3" pattern is not out of the question, but not the best choice, as it becomes an avalanche of other changes to the front hubs, brakes, etc.

Fabricating on the rear suspension cradle to accept the Getrag 226mm LSD does not appear to be heart stopping. Before I break out the torch and welder, however, I want to solve the axle problem. Sure, I can call and get custom axles made, but an off the shelf, OE solution is better from a cost and logistics standpoint. I do not mind using parts from several different types of vehicles.

I will begin posting pictures very soon. I really welcome input from anyone who might have attempted this, or have direct knowledge on the subject. Thanks!

 

OK, so I haven't forgotten about this! Actually, progress has been made. I decided to dial back a bit and go with the HAG215 rear differential. This differential is found in a variety of MB vehicles, but is also found in a plethora of Chrysler products, including Chrysler 300, Dodge Charger & Challenger. It was installed behind several engines, including the 6.1L Hemi. The bad news is that all of the HAG215's are open differentials. For me, though, it is OK, as I have a brand new, in the box Wavetrac for this differential.

There are two inherent problems with installing the HAG215 into the R170 based Crossfire. First, the HAG215 uses a larger inboard CV joint and spline. Second, unlike the stock Crossfire differential, the HAG215 does not have nice, equally spaced rear mounting points. It has an "arm" on one side, causing mounting issues. I will tackle these items one at a time.

First, the axle. I imagine that there exists an off the shelf solution to the problem of the larger inboard spline. My best guess is that the R171/172 based SLK55 probably uses the exact axle we need. However, I couldn't find a parts store anywhere that stocked this axle, nor could I find technical specs, such as compressed length, inboard and outboard spline counts, diameters, etc. My gut says that the SLK55 is the answer. Short of that, I went a more difficult route. I acquired two axles. One for the Crossfire and one for a Dodge Charger SRT-8 6.1L. I bought aftermarket, from the same company. My hunch was that I could disassemble both shafts, do a little parts bin engineering, and voila! A hybrid axle, just like I need. I'll save you the suspense: it works! Pain in the rear, but I was able to build a hybrid axle that I feel confident in this evening. Score one!

Second, the offset rear mountings of the HAG215. My next hunch will be that a R171 rear crossmember, which features both the R170 style mounting AND the HAG215 mounting will work. Why do I say that? Well, from searching the parts sites, all but one rear suspension link are the same as the Crossfire. Leading me to believe that all of the geometry is essentially the same. Tomorrow, I will order up an R171 crossmember from a local junkyard, and I will compare it to the Crossfire rear crossmember (I have an extra on my shop floor, now), and I will get moving on that.

Pictures will begin to be posted this weekend. This is not a project for the faint of heart, but this solves a few major problems all at once. First, the easy acquisition of many different Limited Slip Differential (LSD) options, gears, etc. The aftermarket support for the 300/Charger/Challenger is insane. So many options! Second, the HAG215 will put up with a ton of power, compared to the stock differential. Third, the offset rear mounting is designed to offer some lever arm to the differential housing, reducing wheel hop.

I've spent quite a bit of money on this project already, but I do not mind. I like these kinds of projects! My goal is to solve this for my own car, and then post up the formula, so that someone else can also do it, without the trial and error, wasted time and money. Look for me to get more active with this in the coming days.


p.s.- I am doing this work along with a transmission overhaul/improvement. Oh, and an M113K swap, all at the same time

 

Bring it to the Tail of the Dragon this fall, there are over 60 owners that would love to see it ! CLICK

 

That is the game plan.

 

OK, second pair of axles have been ordered, and will be here tomorrow. Now that I know what has to be done, I will more carefully document the process. I also ordered an R171 crossmember, which is scheduled to be delivered here on Monday. Driveline comes out of my 04 SSB this weekend. Before it does, I will put the car on corner weight scales, to document the upcoming changes to the weight profile. In addition to the engine, I have to also add the intercooler radiator, pump, hoses and several other ancillary items. I have read that this does not add a ton of weight to the car, but I do not see how that is possible with the addition of these items, two more cylinders, and a supercharger. The weight difference on an SRT-6 would be considerably less. BTW, this car already has SRT-6 brakes, suspension and wheels, so perhaps it is not too far off the mark, in certain respects. Other than the wheels and the front bumper cover, I have tried to keep exterior mods to a minimum, as I prefer the looks of the standard coupe, to the SRT6 (spoiler, mainly). Once ready, I will post the driveline swap in another thread, and reserve this one for the actual mods required to put a very much uprated rear end together.

Back on topic: Not counting the Wavetrac, rough accounting says that we are currently in the $950 range for the swap, including all four axles, the R171 crossmember, and the low mileage HAG215 I purchased. Axles came from Rockauto (I will post links), R171 crossmember I found online from a junkyard, via car-part.com, and the HAG215 I got for $300 at a swap meet. I didn't get any special deals on any of this (other than the new in box Wavetrac, which I "stole" for $450). That's really not all that bad, considering the big leap in reliability that the larger differential will offer, and the commonality for aftermarket upgrades. People in other communities pay a whole lot more for rear axle upgrades!

Lastly, from what I can see, the HAG226 might be a drop in after this (just need to change the pinion flange to a 3 bolt one), and it already comes with an LSD. I see those trading hands for $250-600, depending on details and timing.

 

Hi nemiro

I think you should keep the 4 bolt diff flange if you're upgrading to the M113K. When I did my car I used a transmission and driveshaft/tailshaft from an SL55 and kept all the 4 bolt flanges. I used a modified SL55 driveshaft/tailshaft as it has larger splines and a larger centre bearing that bolts straight into a Crossfire. The 4 bolt flanges on the Mercedes diffs also fit the stock Crossfire diff.

 

Good info! unfortunately, nothing I have on hand right now is 4 bolt. However, I will take that under advisement as I keep upgrading.

 

maybe this will help,,, https://www.crossfireforum.org/forum...mited-srt.html ,,, already done ,,,in a crossfire and testing as we speak. again plug and play no mode to your crossfire and keep your srt6 or limited diff and tcu as back up or to reinstall when u r ready to sell jim

 

Interesting. So are you using the HAG215 and the R171 crossmember, or did you modify the stock crossmember, or did you weld on an extra fitting to the rear diff cover? I have considered all three of these, and one or two others. I want to stay with the 3.07 ratio, and this HAG215 I have is already built with it, so bonus there.

Certainly not trying to step on your toes, nor am I looking to sell any of this. This is NOT a turnkey solution, but it is a way.

 

,,

you said "so are you using the HAG215 and the R171 crossmember, I to don't want to step on anyone's toes buy your info toward what i am doing to is not correct example "no don't know where you got that info but wrong.. again you said "or did you modify the stock crossmember, or did you weld on an extra fitting to the rear diff cover" No again the setup i and Tom came up with does no change a thing on the crossfire. as i said the stock parts that came with your car srt or limited can be reinstalled whenever you want a few members would like a different ratio for their car I mean like a 3.91 or 3.64 in limited makes it almost a second faster in the 1/4 mile that is if it doesn't spin the tires off. lol keep up the good work, we need good modifications for gas mileage and performance jim

 

OK. Well, I will watch your project with interest, for sure!

 

and I will also keep an eye on your diff change, thanks for doing what you are doing ,, when you can get it to work lots of members will interested. I though years ago that getting the wave track for our members would not work,,,myself and some others we got it made,, i had put the first one in my V* as a test knowing it it held up in a V8 crossfire the srt6 and limited would have no problem,, spoke to the owner of unatrex about 9 months ago and if we ( crossfire members) got an order of 15 wavetrac's he would remake them. this is why i am tring to get a plug and play diff with posie unit in it for what we would pay today for a wavetrac. good luck keep up the good work. jim

 

When this all started, I just wanted a Wavetrac. I wound up with the one I have, naively hoping it could be modified to work. The led me to the HAG215, and eventually to the HAG226 as an even more cost effective option. It may yet be. However, I will likely stop at the HAG215, if it can be made to work.

BTW, the stock Crossfire cross member could be modified to work with the HAG215, thereby eliminating the expense and fuss of trying the R171 crossmember. I chose the route I did, because the R171 member may offer a completely bolt in swap, requiring no fuss, or questions about anyone's fabrication abilities. I won't know until probably next weekend, if it will work, or not. The 04 SSB goes under the knife in the next few days. I'd be there already, but I just picked up an 05 SRT-6 (grey) with 43k miles this afternoon. We're back up to 2x limited and 2x SRT-6's around here!

 

Not a whole lot to report at the moment, but did want to post up that the R171 rear subframe is not going to be the solution we are looking for. While laid out in almost exactly the right way for what is needed, the main frame mounting pads are about 2" further apart in all dimensions. The suspension pickup points are moved a proportionate amount. I liked this frame, as it would have allowed a bolt together option.

A bit of a setback, but I will move on. No I will look at two options. First will be to simply weld an aluminum block with a tapped hole to allow the HAG215 to bolt into the stock location, and the second will be to add a third mounting bushing to the R170 subframe, exactly how the R171 subframe had it setup.

 

Not quite as deep into it as you...yet. Finding a Wavetrac is next to impossible so any other solution for LSD is needed. Running on 11" A7's I need all the power to the pavement. Thanks for pioneering!

 

Hello, I to have interest in a LSD setup but the Wavetrac is pricey by my standards. At this time I am driving a R170 car (slk230k) pre facelift and came across this options. Going direct I was able to get this to the door for just over 200.00. If you are looking for LSD this may be another option for XF owners.I am not sure after reading this thread if the XF has the 185mm Diff but this kit clearly states it fits the R170 platform. Also if you download the app you get another discount bringing the cost to under 200 bucks to the door. I hope this helps someone in the hunt for a reasonable LSD setup for the R170. I can say that the fact that my SRT6 did not have LSD was a factor when it came to selling the car. These are selling for around 300 with tax on flea bay so using the app you are saving over 100 bucks! I can post the link if interested. I found this info today, so the slk230k and the Limited XF both have 3.27 ration but the ring gear is smaller in the MB SLK. I do know this LSD kits is for the 185mm ring gear so that may be a issue for the XF crowd. I read somewhere that it was easy to install the LSD but on ebay they say have it installed by a shop. Cheers! GG

Pr

 

What brand is this? Have a link? Seems pretty unbelievable that a real LSD would cost so little.

 

Progressive LSD conversion set for Mercedes W124, 190E, slk230 oem differential

https://www.ebay.ca/itm/264083621597

Makes no mention of SLK320

 

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This seller must want a broader customer base, right? Seems to me a contact to the seller could answer any questions regarding what applications it could also be used for. If you know the XF rear end specifics, the answers could come very quickly.


.

 

Believe they are the same. However, that is a Chinese knock off of a Phantom Grip. It has some limited slip ability, but they are a cheap cheat of a way to do it, and almost always wind up with worn, broken parts, and disappointment at the least. They were real popular in an older model of car I used to be in to, and people learned to avoid them.