[M2Blu]

Been wanting to write up a review on the revshift diff kit. If anyone is on the fence about getting it then I hope this review helps.

Been having issues with the car recently and I was experiencing a lot of shuddering from the rear wheels. Felt like the entire diff was loose and clunking around every time I drove the car. Stop and go traffic was a nightmare. Thought the diff was going to be left behind me at some points. Hated driving the car because of it so I decided to get the revshift kit.

Install was a pain in the ass especially doing it without a lift but it is possible. Also threw in my auto solutions short shifter as well

If anyone is interested in an installation write up on either the diff brace/bushings or the short shifter then I could certainly post one up.

Overall I would highly recommend the kit. It completely eliminated the shuddering that I was feeling and tightened up the car to something it should have been like from day one. Of course NVH will increase with this kit especially if you do like I did and go with the stiffer green bushings. Driving it feels like I stole a full on race car from the bmw team warehouse. I don’t mind the noise and vibrations. To me it adds to the experience of what a competition model should feel like, at least in my eyes. The diff sings beautifully now and even better at higher rpm’s and speeds. Low speeds you can hear the gears whine and the clutch chatter when at a stop. Shifter shakes as well but nothing crazy. Replaced all the bushings which includes the front and rear of the diff and transmission bushings. Had to make my own bushing press with some washers and some long screws. Worked flawlessly for pressing them out and putting them back in.

Had issues removing the top bolt from the stock diff brace so I used a stubby impact gun. Broke one ratchet and bent another one trying to get it off by hand. Impact got it off after almost 35 minutes of trying. Not sure what sort of superhuman torqued it on but they never meant for it to come off thats for sure.

There is however an extra unexpected vibration that I feel. Right around 3k rpm in 3rd and 4th gear there is a noticeable difference in the vibrations. Feels driveshaft related, almost like there is an imbalance. Took the car to bmw to get looked over and of course they couldn’t find anything wrong and they confirmed that everything was installed properly and in spec.

Figured softer transmission bushings would solve the issue so I ordered a set from revshift and swapped them out. Helped decrease the NVH by a bit and helped significantly with the other vibration but did not get rid of it entirely. My next solution is replace the driveshaft center support as that is in my opinion the weakest link in the driveline. I’ll update once I get that sorted out.

All in all it is definitely a worth while mod, total cost was right around $700 for all the parts excluding the short shifter. You can expect a shop to quote you $3-400 for the shifter and north of $1000 for the brace and bushings.

[bitcore]

Thanks for posting this. I would absolutely love an installation write-up since this is something I'm strongly considering.

Did you have to drop the subframe? Did you have to disconnect the driveshaft? How long did the install take you? Do you have any details on the bushing press tool that you made (washer diameter, etc?)

[M2Blu]

Originally Posted by bitcore

Thanks for posting this. I would absolutely love an installation write-up since this is something I'm strongly considering.

Did you have to drop the subframe? Did you have to disconnect the driveshaft? How long did the install take you? Do you have any details on the bushing press tool that you made (washer diameter, etc?)

Yeah I can definitely write something up. Going to be doing the center driveshaft support within the next couple weeks so I’m gonna use that time to check everything and make sure it’s all still good and I’ll snap some pictures to help with the write up.

But yes the subframe does have to be dropped however only about 3-4 inches. The way that I did the job I did not have to disconnect anything from the car so the driveshaft, rear suspension, brakes and most sensors were left untouched. But regardless just be careful and keep an eye on everything to make sure it’s not stressed when lowering the subframe. Also a huge thing to be mindful of is when using the extended subframe bolts make sure to keep an eye on how much thread is left still on them as you don’t want to back them out to much or you’ll risk the subframe falling out completely.

Hard to estimate the install time since I worked on it each day after work for a couple hours so I would guess somewhere around 9 hours roughly. But this was with me rolling around on the garage floor and having to get creative with tools. Plus I’ve sort of have ocd when it comes to my car so that includes checking everything multiple times lol. I think realistically if I had to do it again I would be able to do it right around 6 hours give or take maybe less. Having the right tools and maybe some quick jacks or a lift would have made this job miles easier.

In the write up I’ll include any special tools I used and details on the bushing press I made. It was honestly a very crude way of doing it but I sure as hell wasn’t going to buy an expensive set and wait weeks for it to deliver. The entire tool cost me less than 8 dollars to make

[Telluride]

Originally Posted by M2Blu

Been wanting to write up a review on the revshift diff kit. If anyone is on the fence about getting it then I hope this review helps.

Been having issues with the car recently and I was experiencing a lot of shuddering from the rear wheels. Felt like the entire diff was loose and clunking around every time I drove the car. Stop and go traffic was a nightmare. Thought the diff was going to be left behind me at some points...

I went down the same path with the KMP Rear Diff Brace and offset bushings, as my car is lowered. However, I had my local shop install.

In full agreement with your summary... huge improvement all around and completely eliminates wheel hop!

[Track/S]

Doing this work on the ground is fu.... crazy, I don't recommend it to anyone.

[medphysdave]

Originally Posted by Track/S

Doing this work on the ground is fu.... crazy, I don't recommend it to anyone.

I'm not sure I would do this with my quick jacks. If the time comes this might be something I pay a shop to do.

Anyone have shop estimates for labor to install parts?

[Track/S]

Originally Posted by medphysdave

I'm not sure I would do this with my quick jacks. If the time comes this might be something I pay a shop to do.

Anyone have shop estimates for labor to install parts?

I think iam2slow know how much the labor costs.

[iam2slow]

Originally Posted by Track/S

I think iam2slow know how much the labor costs.

Originally Posted by medphysdave

I'm not sure I would do this with my quick jacks. If the time comes this might be something I pay a shop to do.

Anyone have shop estimates for labor to install parts?

I just got this done with a shop which charged me $1050 for ~5-7hrs labor for the diff lift kit and a front pinion seal. You could probably find a shop that could do it for cheaper depending on your area.

[Telluride]

Originally Posted by iam2slow

I just got this done with a shop which charged me $1050 for ~5-7hrs labor for the diff lift kit and a front pinion seal. You could probably find a shop that could do it for cheaper depending on your area.

My shop charged for 6 hours of labor. However, they also installed a midpipe along with the swapping of new rear diff brace.