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Thread: URGENT! Revshift diff bushings question for E36

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    URGENT! Revshift diff bushings question for E36

    Well, I have a big autocross event in 2 weeks and need to figure out an issue I have with my REVSHIFT differential bushings. I've called and emailed with no response, so I am relying on the forums now.

    Has anybody had them force themselves loose and back out? I know I tightened the diff bolts to 75 ft-lbs, but all 3 bushings have backed out.

    I'm hesitant pressing them in and having them back out again. I want to run the Revshift front diff bushing with stock rear diff cover bushings. Is this possible?

    Thanks to all that can give some advice!
    Last edited by MINIz guy; 05-21-2018 at 08:55 PM.

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    Rear cover bushings and front diff bushing...


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    URGENT! Revshift diff bushings question for E36

    Weird, did the bolts back out?
    Are the large diameter washers supposed to ‘sandwich’ the differential cover?

    If you need something more than OE/OEM (Lemforder) then use interference fit aluminum.


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    Last edited by bluptgm3; 05-21-2018 at 10:53 PM.

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    Time for turnermotorsports Diff mounting kit or akg or Oem.


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    S54B32 E36 M3 DTA S100 Sedan Street car full swap:
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    The bolts must have backed out, but I’m unsure why. The bushings were flush with the subframe and cover, and bolts torqued to 75ft lbs.

    Didn’t think Revshift was low quality but their customer service leaves a lot to be desired. I waited a week before they shipped these out last year...

    If nobody knows an answer to whether I can run stock cover bushings with the Revshift front bushing, then I will have to look at poly alternatives. No time to drop the subframe to press in the front bushing.


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    That's weird. I personally wouldn't run 2 OEM an 1 poly bushing on the diff.

    I guess there's a chance the poly bushings 'set/compressed' after a few hundred miles, reducing tension on the bolts, allowing them to loosen. Did you torque to 75ftlb on install, then not recheck after a few miles/events?

    Either way, a possible temporary fix is to locktite and retorque. I can't remember how easy it is to back-out all 3 bolts, but if difficult, use wicking locktite.

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    Quote Originally Posted by aeronaut View Post
    That's weird. I personally wouldn't run 2 OEM an 1 poly bushing on the diff.

    I guess there's a chance the poly bushings 'set/compressed' after a few hundred miles, reducing tension on the bolts, allowing them to loosen. Did you torque to 75ftlb on install, then not recheck after a few miles/events?

    Either way, a possible temporary fix is to locktite and retorque. I can't remember how easy it is to back-out all 3 bolts, but if difficult, use wicking locktite.
    I checked after 150 miles of street driving and nothing had loosened. I did the job at my parents house and then drove it down to mine, distinctly remember checking it at work because I had this exact fear. But it's been to multiple track/autocross events (<10) after that and I finally rechecked after this winter.

    Called Revshift again and still no answer. I'm thinking of getting the ECS diff bushing kit for $77 and calling it good...
    Last edited by MINIz guy; 05-22-2018 at 10:55 AM.

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    I agree on not mismatching the diff bushings. You want the forces evenly distributed among them. I'd go OEM or 95A poly. I've had AKGs in mine for a few years with no issues. Do the RevShift ones have metal sleeves inside? If not, that's prob where things went wrong.

    https://www.akgmotorsport.com/produc...yurethane-95a/

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    http://www.revshift.com/product-p/pdb-e36.htm

    Sure do, so I'm at a loss. I'm in a time crunch anyway and don't want to spend the cash right now for more bushings... may have to just press in bushings again and nurse it over the next 2 events.

    Thanks for the help guys!

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    Is there a metal tube inside the bushing? Or are you just tightening against the poly??? I don't know why people continue to try revshift stuff ... semms like nothing but issues. Stick with the know good stuff. For a track car, solid aluminum is the way to go.

    Nevermind ... just saw the posts above, lol
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    I've heard of one or two others having this issue, but mine that I installed a couple months ago are fine. I hammered the bushings in dry as well, and I'm fairly certain they aren't moving anywhere, ever.

    The other guy on the M3 forum who was having difficulty I think had extra space in his subframe between the front/rear mounts for whatever reason. This allowed the diff to slide slightly on the bushings without the bolts coming loose.

    If your bolts are actually backing out and that's what's allowing the bushing movement, put some blue loctite in there and make sure they're torqued to spec (front is 75ish I think, but rears I think are only 50-something). With the bolts secure the bushings in theory shouldn't have anywhere to move.

    Also, my kit only had a big washer for the front bushing. The rears were designed to have the bolts go straight into the recess on the bushing with no washer. If I was to put washers on my rears with the bolts they provided, they wouldn't be nearly long enough to engage properly.

    Disclaimer - my front diff bolt hole is drilled out and I secure it with a longer bolt and a nut on the backside against the diff case. The bolt I use is the same type and grade as what was provided, just longer.
    Last edited by TostitoBandito; 05-23-2018 at 02:40 PM.
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    I'll take some pictures this weekend of what my stuff looks like apart. Finally got a hold of Revshift after 3 calls and 1 email, and they were of no help. They said they've had that same complaint but can't attribute it to anything.

    I thought Revshift stuff was good before, not anymore! Will make due because this weekend is a time crunch, and if they loosen again, out they come for better stuff.

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    I have been running OE rear diff bushings with AKG 75D front bushing for over a year now on a primarily track/autox car, seems to be just fine. Reason was I was lazy when swapping diffs (for ratio reasons) and didn't swap covers, but I honestly haven't noticed any issue with running it that way.

    My AKG diff bushings have been fine over the last few years and two diffs. Subframe bushings I'm not impressed with, but the diff ones have been great.
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    There should be a lip/cup on the metal sleeve as many other manufacturers do for these bushings.

    I had issues with E46 diff mounts by RS. They claimed to be re-engineering and would have a new set of the re-engineered part in 2-3 weeks. That was in April 2016. No new bushings.

    Use the Rogue Engineering mounts. Best setup available.
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    Quote Originally Posted by 95///M3 View Post
    There should be a lip/cup on the metal sleeve as many other manufacturers do for these bushings.

    I had issues with E46 diff mounts by RS. They claimed to be re-engineering and would have a new set of the re-engineered part in 2-3 weeks. That was in April 2016. No new bushings.

    Use the Rogue Engineering mounts. Best setup available.
    That's a good point. I don't know if they co-mold the polyurethane with the metal sleeve, but that lip would definitely stop the sleeve from moving so easily and doing what you see.

    I pulled the diff today. The washers were cupped from the diff moving around. I blue threadlocked the bolts when putting it back in. Unfortunately I couldn't get the cover off due to using "The Right Stuff" RTV and it being so damn good. Oh well, I only gotta nurse it for a few more events.

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    My diff bushings did not have any washers. You sure you have the right ones - no subframe or something on accident?

    Unless they are an older style?

    Here are my Revshift bushings

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    Quote Originally Posted by GG Emerican View Post
    My diff bushings did not have any washers. You sure you have the right ones - no subframe or something on accident?

    Unless they are an older style?

    Here are my Revshift bushings

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    Mine also looked just like that. No washers on the rears. Only the front bushing had a washer. As I said earlier, if using washers on the rears with these bolts (and not longer ones) you'd barely have any threads engaged and they'd probably back out super easily.
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    Nope mine definitely don't look like that. I got them and they were clearly labeled E36 differential bushings and came with 3 washers in the bag. I remember 3 bolts too, but the Revshift site only shows two bolts. http://www.revshift.com/product-p/pdb-e36.htm

    Also no way I could get the bolt inset like that. The aluminum sleeve goes the entire depth of the poly bushing, so if it was inset, I'd have a lot of aluminum sleeve showing on the other side.

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    I bought mine directly from Revshift last December, so assuming you also got yours from Revshift recently I'd say they either changed their design (unlikely) or sent you the wrong bushings. I know they are terrible to get a hold of via email, but see if you can track down a phone number for them and talk to someone. Show them the pictures in this thread compared to what you have and ask them to explain.
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    I wanna say I got mine the summer of 2016, so they are older than yours. I'd be curious when GG Emerican got his.

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    It was around summer of 2017.

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    Sounds like I got an older version but I will have to call after my events next week. I just don't have the time to worry about the autocross car when my daily driver Tahoe has been down for a few weeks...

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    I have the same ones, the older version. I've had no issues myself in my LS swapped E36 for 3+ years.... Something is definitely going on. If you still have this problem, I can contact the owner directly to get in contact with you!

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    Quote Originally Posted by Inflame View Post
    I have the same ones, the older version. I've had no issues myself in my LS swapped E36 for 3+ years.... Something is definitely going on. If you still have this problem, I can contact the owner directly to get in contact with you!
    I'll PM you if I still find problems after blue threadlocker. I put 1 event on it this weekend and will check on it tomorrow. My next event is next weekend, so I can't pull the car apart again.

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    These designs without a central sleeve reveals a disturbing lack of understanding on the part of the supplier both about how this elastomeric bushing configuration is supposed to function, and how fasteners work.

    The central sleeve serves a couple of purposes. One is to set the desired bushing stiffness by compressing the elastomer a controlled amount on installation. Omitting the sleeve and trying to use fastener torque instead will give vague and inconsistent results at best. The other purpose is to allow torquing the fastener enough to stretch it properly. This provides high clamping force, keeps the fastener from backing out in use, and minimizes fastener flexing and potential fatigue breakage from its single-shear loading.

    Considering that central sleeve bushings are readily available — in fact they're the norm — there's no reason to be having a discussion about how to coax the other kind into working, or what type of Loctite to use on the bolts to stop them from coming loose.

    Go buy some properly designed bushings and leave it at that. PowerFlex blacks (they fixed the washer issue several years ago) work fine on a track car, or get the alternate brand of your choice. Just make sure they're properly designed.

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