[Nexus313]

Hi all,

Just wondering if anyone has done rear diff bushings on their F30 yet? I'm noticing a clunking noise from my rear diff when shifting into gear 1st from a stop, and even 1-2 shift at low speeds, and a vibration on the highway from the rear end. Just wondering if anyone has anyone ever done rear diff bushing on these cars yet or ran into similar problems? Overall it's smooth on local roads / local speeds.

FYI - My wheels and tires are brand new - road force balanced. Plimit under 9LB for most wheels.

[brigade24]

I changed my rear differential bushings last year. there was no noise or anything, it was for performance..the 2 front differential bushings are not that difficult to access or remove.

the one mounted in the subframe is a pain...you will need to lower the differential and the subframe to access and remove that bushing.

[Nexus313]

Originally Posted by brigade24

I changed my rear differential bushings last year. there was no noise or anything, it was for performance..the 2 front differential bushings are not that difficult to access or remove.

the one mounted in the subframe is a pain...you will need to lower the differential and the subframe to access and remove that bushing.

Which rear diff bushings did you go with? Any real performance gain?

[Eschmacher]

Originally Posted by Nexus313

Hi all,

Just wondering if anyone has done rear diff bushings on their F30 yet? I'm noticing a clunking noise from my rear diff when shifting into gear 1st from a stop, and even 1-2 shift at low speeds, and a vibration on the highway from the rear end. Just wondering if anyone has anyone ever done rear diff bushing on these cars yet or ran into similar problems? Overall it's smooth on local roads / local speeds.

FYI - My wheels and tires are brand new - road force balanced. Plimit under 9LB for most wheels.

Does your vibration occur right around 65ish? I have a similar clunk in the driveline and a vibration as I accelerate through 60-70, worst at 65.

[brigade24]

Originally Posted by Nexus313

Which rear diff bushings did you go with? Any real performance gain?

I went with the delrin bushings for the subframe and differential. The bushings for the former where from bimmerworld and the latter were from condor speed.

[Nexus313]

Originally Posted by Eschmacher

Does your vibration occur right around 65ish? I have a similar clunk in the driveline and a vibration as I accelerate through 60-70, worst at 65.

Yep.. those exact speeds. But it only happens as I'm cruising along the highway consistently at those speeds. it's hard to notice it on local road speeds, actually feels butter smooth on local roads, it appears to be intensified roads such as the highway. Strange!

What's weird is I can do a pull on the highway on ramp to 100-110mph and it'll be butter smooth through the pull but as soon as I let off the throttle and begin cruising I start to feel that rear end shutter!

I'm running low profile Conti extreme sport, with h&r springs. The tire shop did notice my rear wheel had an EVER so slight bend on the inner side, so I'll get it straightened and let you know if that fixes it.

[Nexus313]

Originally Posted by brigade24

I went with the delrin bushings for the subframe and differential. The bushings for the former where from bimmerworld and the latter were from condor speed.

Cool! Did you DIY it? If not, how much would a shop charge to do the subframe and diff bushings? It would be nice to fix this issue and get some better handling

[Eschmacher]

Originally Posted by Nexus313

Yep.. those exact speeds. But it only happens as I'm cruising along the highway consistently at those speeds. it's hard to notice it on local road speeds, actually feels butter smooth on local roads, it appears to be intensified roads such as the highway. Strange!

What's weird is I can do a pull on the highway on ramp to 100-110mph and it'll be butter smooth through the pull but as soon as I let off the throttle and begin cruising I start to feel that rear end shutter!

I'm running low profile Conti extreme sport, with h&r springs. The tire shop did notice my rear wheel had an EVER so slight bend on the inner side, so I'll get it straightened and let you know if that fixes it.

If/when you figure out the problem, please let me know! It's the only thing wrong with my car at the moment

[Nexus313]

Originally Posted by Eschmacher

If/when you figure out the problem, please let me know! It's the only thing wrong with my car at the moment

Will do! Is your car a manual? I was thinking it could be the guibo, center support bearing aswell if not the diff mounts. More likely to go out on a manual. Supposedly those can make clunking noises and vibrations if gone bad aswell. I'm going to straighten my rear wheel first and go from there.

[Eschmacher]

Auto, started when I got my M-LSD installed. Happens with both my winter and summer wheels, so I know it's not that.

I do have a spare guibo I'm going to install, but I'm more apt to think the shop damaged my rear diff mount during install.

[Nexus313]

Originally Posted by Eschmacher

Auto, started when I got my M-LSD installed. Happens with both my winter and summer wheels, so I know it's not that.

I do have a spare guibo I'm going to install, but I'm more apt to think the shop damaged my rear diff mount during install.

I don't think they damaged it, they might have not properly installed it. Check your torque specs for the diff bushing bolts. There's two in the front, 1 in the back. Start with torque specs on those two front bushing bolts, it's pretty easy to get to. With these cars everything needs to be in spec.

[brigade24]

Originally Posted by Nexus313

Cool! Did you DIY it? If not, how much would a shop charge to do the subframe and diff bushings? It would be nice to fix this issue and get some better handling

you will def get better handling.

I DIY'ed it...not sure how much a shop would charge to do this work. I can't see it taking less than 3-4 hours to do so factor that into your calculations.

[Polo08816]

Originally Posted by brigade24

you will def get better handling.

I DIY'ed it...not sure how much a shop would charge to do this work. I can't see it taking less than 3-4 hours to do so factor that into your calculations.

I had to re-read that and thought you said you can't see replacing the subframe bushings taking up more than 3-4 hours lol. It took me 3-4 hours just to replace the factory open diff with my M Performance Diff.

[brigade24]

Originally Posted by Polo08816

I had to re-read that and thought you said you can't see replacing the subframe bushings taking up more than 3-4 hours lol. It took me 3-4 hours just to replace the factory open diff with my M Performance Diff.

lol...less than 3 hours is some serious wishful thinking

[Eschmacher]

Originally Posted by Nexus313

I don't think they damaged it, they might have not properly installed it. Check your torque specs for the diff bushing bolts. There's two in the front, 1 in the back. Start with torque specs on those two front bushing bolts, it's pretty easy to get to. With these cars everything needs to be in spec.

Did you ever figure this out, Nexus?

[Nexus313]

Originally Posted by Eschmacher

Did you ever figure this out, Nexus?

Nooooope. Left it as is. Rear end still clunks occasionally at stand stills and have vibes from the rear end when cruising on highway speeds.

It's likely the rear diff bushings. I'm getting some new winter wheels soon to see if it narrows it out because I have quite a few bends with my current setup.

[Eschmacher]

Originally Posted by Nexus313

Nooooope. Left it as is. Rear end still clunks occasionally at stand stills and have vibes from the rear end when cruising on highway speeds.

It's likely the rear diff bushings. I'm getting some new winter wheels soon to see if it narrows it out because I have quite a few bends with my current setup.

Mine has turned out to be the diff apparently... working on a replacement now. I'm also thinking I will get my diff mounts replaced for peace of mind. maybe even get the softest powerflex inserts in addition.

[jbiswurm]

Originally Posted by brigade24

I went with the delrin bushings for the subframe and differential. The bushings for the former where from bimmerworld and the latter were from condor speed.

I have the bimmerworld delrin subframe bushings. I just fitted the turner motorsports delrin aluminum diff bushings.

I get a serious amount of noise (to be expected to some degree), but its not really gear whine, its more load based, especially on a poorly rev matched downshift where there a lot of overrun induced driveline stress.

What has your experience been with noises?

I have a relatively new wavetrac unit in as well so i am trying to make sure nothing is broken!

[Polo08816]

Originally Posted by jbiswurm

I have the bimmerworld delrin subframe bushings. I just fitted the turner motorsports delrin aluminum diff bushings.

I get a serious amount of noise (to be expected to some degree), but its not really gear whine, its more load based, especially on a poorly rev matched downshift where there a lot of overrun induced driveline stress.

What has your experience been with noises?

I have a relatively new wavetrac unit in as well so i am trying to make sure nothing is broken!

The delrin subframe bushings are on my to do list. When I do those, I'll probably just replace the OEM diff bushings. I don't really see a need of having delrin diff bushings.

[jbiswurm]

Originally Posted by Polo08816

The delrin subframe bushings are on my to do list. When I do those, I'll probably just replace the OEM diff bushings. I don't really see a need of having delrin diff bushings.

They are so awesome - you will not be disappointed. As of right now if i could do it over again thats the approach i would take.

That said the solid diff mount related noise is not enough to warrant pulling everything apart again to reft stock bushings. Its kind of a PITA job.

[Polo08816]

Originally Posted by jbiswurm

They are so awesome - you will not be disappointed. As of right now if i could do it over again thats the approach i would take.

That said the solid diff mount related noise is not enough to warrant pulling everything apart again to reft stock bushings. Its kind of a PITA job.

It is a huge PITA job. Dropping a rear subframe is not a joke. My rule of thumb for estimating the time it takes to complete a job that I've never done before is to just multiply the BMW book time (KSD) by 5. The times they have are based on a tech having done the job before and having the best tools to do so.

While I can probably get it all done in 2 days provided I have a hydraulic press, this might be one of those things to just pay a shop to do along with replacing some of the bearings and guibo associated with the driveshaft at the same time as the subframe bushings and diff bushings.

[jbiswurm]

Originally Posted by Polo08816

It is a huge PITA job. Dropping a rear subframe is not a joke. My rule of thumb for estimating the time it takes to complete a job that I've never done before is to just multiply the BMW book time (KSD) by 5. The times they have are based on a tech having done the job before and having the best tools to do so.

While I can probably get it all done in 2 days provided I have a hydraulic press, this might be one of those things to just pay a shop to do along with replacing some of the bearings and guibo associated with the driveshaft at the same time as the subframe bushings and diff bushings.

Then multiply the whole thing x2 because you messed it up and need to do it over again!!