Join Date: May 2012
Location: Avon Park, Florida
My Ride: 2002 BMW 325i
Obvious but undiagnosable vibration help for you!
I bought a 2002 BMW 325i from an auction as my first retirement project. I have been driving B's since my first tour in the military stationed in Bremerhaven, Germany in mid 80's. I went from head to toe on this B wanting to get it as close to perfect as a ten year old car could be on a budget. So 2000 for the car and a budget of 2000 for parts. All labor done by myself with the help of the fine people on this excellent site, google and YouTube. Well, after 7 months my jobs is done. Replaced all vacume hoses, all 20 feet of it. Repairs or replaced faulty parts. Fluids and filters. Couplers and connectors. Missing screws and expanding plugs. Isolators and mounts, vanos seals and gasket sets. After replacing the transmission mounts, there developed a slight vibration during take off, and getting into 4 th gear in the steptronic. All occurring at about the same rmp range. Plus I could replicate vibration while parked in garage pressing the gas and hitting the same rpm range. Normally between 1300-2000. Give or take a fue. I removed all components on the front of the motor one at a time, no solution. I rechecked torque on new engine mounts. No solution. I next verified torque on botom of trans mounts. Reduced to 10 ft lbs. and used locktite on nuts. Better but still there. So I installed, I call them "sub mounts". Tools needed, 2 ton rolling floor jack preferred. Don't try to use the BMW car jack. 13 mm socket with short extension is good. A pointed object such as scribing tool or center punch to line things up. Dot use screwdriver, possible thread damage. Snext go to your favorite parts store and get the following: 1 package of shock and end link bushings, make sure they are the rubber ones not poly as the rubber will isolate and the poly will transfer. 4 come to a pack.the ones I chose where for ford specific. Made by Dorman. Next 1 package of 965-011 5/16" (M8) flat washers, also made by Dorman. Now 1 package of 980-440 (M8) 1,25 x 40 mm bolts. And of course make sure you still have some locktite on hand. Process: put car on ramps high enough to gain access to trans cross member using jack stands for safety. Wiggle yor jack and all your tools and parts with adequate lighting under car. Best to work from passenger side. Take jack with block and support transmission, do not raise it just take the pressure off of the mounts do not want to stretch them. With trans pressure released undo the four crossmember bolts. Mark the member alignment before unbolting. You should see the mount drop when each bolt is released. It is aluminum so best to do a quarter drop at a time not to stress aluminum on each bolt. Once all are out, slowly drop trans jack just until the bushings will fit between frame and crossmember. The bushings in the package are slightly different thickness, maybe 1 or 2 mm. No biggs. I placed the Thicker ones on the rear of the crossmember bolt points and and the other slightly thinner on the front. Logic being tilt member toward transmission than away. Even though it is just so slight. Once bushings are in place raise transmission to the point of bushings a hair below frame. Not touching yet. Align bushing with hole, apply washer andlocktite to threads of 40 mm screws and insert screws. Tighten just to the point of touching the crossmember. Once all four screws are in place lower jack and let mount and trans hang in normal state. Or a relaxed position. Key being no stress on any one mounting point. Like neutral buoyancy. And no stress on center bearing on driveshaft. Now the key operation of all. Turn each screw half a turn at a time until rubber isolator just touches the framers each corner. *******!!!!!!! Just going ahead and torquing them down to around 10 ft lbs might cross your mind, back await from the torque wrench, and place it on the ground! Using a large bladed, flat tip screw driver push each side of the crossmember, towards the previously made marks, at the beginning of process. If you can not get it all the way there, then close enough will do, point not to put undo stress on trans mount that will only compact the mount or stretch the mount oh so slightly, but will still translate into direct vibration transfer to frame. Once close enough or on the mark, using 13 mm socket and drive, tighten both screws by turning the rachet only 360 degrees. One turn that's it! Go to the other side of the crossmember and perform the same process. Please remember key points raise crossmember one turn at a time on each bolt, until all bushings touch the frame, test is they will not spin when touched with finger. Remember front is slightly thinner, so requires a couple of extra turns until bushings touch. And only go one complete turn with final tightening. This procedure is in no manual or not a prescribed BMW repair so perform at own risk and liability. But after 7 months restoring this car, it worked perfectly for me! 135,000 plus miles. No weird stumble at startup, no flux in rpms, no jumping engine, no steering wheel shake. No hesitations. Starts, goes to 1000 rpm, smooth as silk, slowly drops as temp rises, to constant 700 or so rpms give or take 50, with no jumpy or bouncy spots during warm up while air pump is on. I don't drive till air pump goes off. Smooth shifting, no dead spots or weird spots in any rpm range. Auto, sport or manual. Total cost $14.00 max. Time, well about 20 mins if you know my car the way I have got to know her over the past 7 months. About an hour or so straight through. I want to hear some success stories. Sorry so long in the tooth, but I find here you must be very specific. Good luck!