James M

My 2003 E55 still has its original motor and transmission mounts and has roughly 70 000 miles on it. 8 months ago I installed longtube headers and a freeflow exhaust. Within the last month I have noticed a nasty vibration coming from the passenger side floor/transmission tunnel area, only in 1st gear and only on a hard pull. My car has been back to the exhaust shop twice this week and we cannot see any part of the headers/exhaust touching or rubbing against any part of the car and the smallest gap anywhere between the exhaust and body is at least a finger width. I have also noticed that my idling has become slightly lumpy when I wait in 'D' at traffic lights. The exhaust shop in question have been building the best headers and exhausts for E55's since forever and continue to do so. Myself and the owner have poked around for 2 days underneath my car and we are aware that the motor twists & shifts slightly when launched hard, but we still fail to see any rubbing marks. I have also just replaced all the steel bashplate bolts, in case it was the cause of the vibration, but to no avail. I am guessing that the culprit could be either the transmission mount or engine mounts or a combination of the two? The engine mounts are so damn expensive and labour intensive to fit that I am hoping it is just my transmission mount (for now)? How can I tell which mount is acting up? Any ideas or advice?

simon1966

My car is in the shop within next couple of weeks to have new motor and transmission mounts along with some other stuff. Mine is a late 2004 with 74K miles. I haven't noticed any vibration but there is definitely excessive movement of the engine when its revved. Seems pretty common at the age of our cars. To be honest I have decided to do it as I'm also having a new sway bar fitted and oil pump chain tensioner done at the same time, so to a certain extent the labour of all 3 jobs overlap so makes it a bit more efficient.

I have heard the issues are quite common when long tube headers are fitted, a lot of people seem to fit flexible joints as there can be risk of the headers cracking with excessive engine movement. I'm thinking of headers soon myself which is another reason I have decided to have new mounts. I have also heard negative things about the flexible joints too, where they basically collapse inside restricting flow!

Hope you get it sorted.

green1212

very difficult question to answer but the tranny mount is not bad of a replacement. the part is not too expensive either, so my advice would be to replace the tranny mount, max 20-30 minutes job and proceed from there. and dont mean to be negative here, but you may have to remove the "headers" to replace the motor mounts?? hope you dont but in some cases you do otherwise you risk "bending" or "denting" the headers. get that tranny mount replaced and see how she goes..... hope that solves it!

Exotic-metal55

Tranny mount is easy change but doubt the vibration is coming from there. Motor mounts usually show up in the steering wheel vibration at idle, when bad. Make sure the headers are not touching the steering shaft, even though vibration is on passenger side. Our aluminum frames can transmitt the slightest vibration and it can drive you crazy!

Quicksilv3r

Just got my car back from the dealer Monday after having both motor & trans mounts replaced, among a litany of other items, and I can say the difference is night/day from the 118K-mile originals they replaced. Had vibrations (not good ones) at idle and under hard acceleration/shifting, but no more. The result is a well composed beast.

MAN55LE

I had a nasty vibration after I had the headers installed, and it was difficult to locate and see, but My dad finally discovered that it was the driver side exhaust lifting under torque and touching the frame was very difficult to see and I also had an inch or fingers width clearance from exhaust to frame. Solution was to either extend the downward section of exhaust to increase the clearance. Or to dent the exhaust where the point of contact had occurred also, you will only able to see the point of contact by removing that section of exhaust or header you may consider using a small mirror almost like a dentist or a mechanics mirror which is flexible ....to help locate the exhaust point of contact with the frame.. hammer worked fine and now there's no rumble in the jungle

MAN55LE

But when I had my headers installed I had also had the motor mounts put in ... So that not to have to do the labor twice, also I use Kleemann headers with a flex pipe add a bung or two for future wideband set up and the transmission mount was very easy to replace be meticulous look it over well.

James M

I will have a look again when I am under my car tomorrow replacing the trans mount. I had the same problem with my C32, now that you mentioned it, and I think we ended up with a crowbar to 're-adjust' some bodywork/heat shield as I refused to 're-adjust' my new exhaust. I swear I have been under my car 8 times at 4 different garages and cannot find this damn vibration.

MAN55LE

I had literally at one point, thought that my header manufacture had sent me a defective product, and had a friend that also checked many times under the car it was only noticeable after removing the exhaust, but you may be able to really accentuate the point of contact by heavily powering the car to cause a very very bad vibration only momentarily and then when you remove or inspect the exhaust or heatshield area, it may become evident where the exhaust is touching. My point of contact was on the left side of the car looking from the rear and when the motor was underload or torqued the exhaust would lift on the left side and dip down on the right side, and where lifted on the left side it would touch the heatshield and then the frame ....only after extreme load (a hard launch) in first gear!

James M

Sounds like me. My exhaust guy actually went as far as spinning the wheels while on the bloody ramp which was 6ft in the air at the time - repeatedly! Mental! Still couldn't find it. I reckon you are dead on the money and the culprit is where the headers go 4 into 1 on the downpipe. What a ***** to remove.

AMG55TECH

The transmission mount is actually very known for causing vibration and there is a pretty easy way to check if it's fully collapsed. Start the car, let it warm up for a minute or two. Leave it in park and bring the RPM up slowly to around 3K then back down slowly... If it's a trans mount, you will fell a "seat of the pants" vibration. As for the engine mounts, this doesn't always work... But it works well if the mounts are fully collapsed... Leave the engine off, open the hood and grab hold of the oil filter housing and attempt to shake the engine left to right. What moves?... The engine or the car? If the engine moves, mounts are probably ok for a while still...if the whole car shakes, mounts a collapsed. Hope this helps.

James M

Thanks for all the input, but the winner is MAN55LE! After spending the morning watching my mate pull the trans mount out (thanks Craig) we could clearly see that the right hand side header had about 2mm clearance between itself and the bodywork, just before it joined 4 into 1. The bodywork could not be 're-adjusted' with a crowbar as it happens to be an important piece that keeps the right hand front wheel from falling off. We could see where the one header tube was rubbing up against the firewall - how the exhaust guys could not see this I will never understand (yes I do - it would require them to rebuild me a new header at their cost!). I am going to explain to them that this is exactly what they are going to do and if I see that they have simply heated the offending tube and flattened it a bit, to create more clearance, then we are going to have a serious problem. No car again for another week while this gets hopefully sorted for the final damn time!!!!! The trans mount replacement went as smooth a silk (20-30 mins without any swearing) but was a complete waste of time and money as the old mount actually had zero wear and felt 'stiffer' than the new OEM mount. Of course after we replaced the mount we had the obligatory testing, which involved multiple hooligan runs with smoking tyres, but as we guessed the header still merrily banged away against the body in 1st gear only. I am damn angry that the 'professionals' wasted my time (5 trips to their factory/5 mornings wasted sitting around) when the problem was evident from day 1.