The moment you buy an older BMW, you must become familiar with a lexicon that includes such terms as DISA valve, DME, Bi-Xenon, SAP, VANOS and, my favorite: guibo.
What sounds like a midlevel thug in La Cosa Nostra is actually something less nefarious. A guibo is slang for the rubber driveshaft coupler, which connects the output shaft of the transmission to the forward flange of the driveshaft. The use of a rubber coupler softens the engagement of the clutch or, in the case of the, gulp, automatic transmission, it softens upshifts.
You can get polyurethane couplers, which tighten up the drivetrain, but I figured since the car had nearly 150,000 miles, even stock replacement stuff would tighten it up to my liking. Yes, the car is billed as the HPD E46, but it doesn’t see much track time, so when things wear out, I usually end up sticking with OEM parts.
The job itself is pretty involved, all things considered, but not terrible overall. I’d rate it a two out of five wrenches, five being the most difficult. The short story is you pull the exhaust, so you can pull the heat shield so you can get to the driveshaft.
Because the job is so involved, it’s a good idea to refresh a few other things “while you’re in there.” You can replace the transmission mounts because they have to come out anyway. You also can refresh the shifter bushings, but that’s another story, because for now, the driveshaft coupler is enough.
I’ve not heard of one failing outright, but the one I pulled out was pretty wiped out. If it did fail completely, the driveshaft likely would remain contained within the tunnel, so to speak, but the forward end of it would probably flail around and do a lot of damage. Replacing the guibo as preventive maintenance is an offer you can’t refuse.
First thing to come off is the exhaust. I like to start at the front and work my way to the rear of the car. The stock exhaust system is one piece, so remove all but one of the nuts from the down pipes to keep things in place while you work your way back. Some penetrating lube helps.There are a lot of fasteners holding on the stock exhaust. When you pull it off and discover how heavy it is, you’ll understand why.These two plates span the transmission tunnel in the middle of the car. They both act as stiffeners for the chassis, but the rear plate also is an attachment point for two exhaust mounts that support the exhaust from underneath.The rear-most exhaust hanger is accessible just forward of the rear bumper to the left of the spare tire well. Two nuts hold it onto studs that are part of the tub.The hanger that holds up the forward left side of the muffler requires and extension and a flashlight to access. Here again, two nuts hold it onto studs that are part of the tub.Support the muffler with a floor jack and remove the nut at the down pipe flange. Lower the system to the ground and celebrate the small victories in life. Thankfully the system routes under the rear axle rather than over it.Remove the heat shield between the exhaust and the driveshaft. I have to say, as heat shields go, those used on the E46 seem pretty well thought out. The material is effective at shedding heat and it isn’t prone to breaking and rattling.Mark the driveshaft and the flange on the differential so you can put it back together exactly how it came apart. The bolts on the flange require a external Torx socket, No. E10.The drive shaft won’t come out without removing the bracket forward of the differential, which you’ll need to support with a floor jack and a 4 x 4 if you have any on hand.The driveshaft carrier bearing is attached with two nuts. It’s a good idea to replace the bearing, too, while you’re in there.Support the transmission with a jack and remove the transmission mounting bracket so you can access the driveshaft coupler.The coupler is attached with three 17 mm bolts and nuts to the driveshaft and three more that attach it to the output-shaft flange on the transmission. Odds are good the new coupler kit will come with new nuts and bolts. If not, be sure you get some.Remove the three bolts that hold the coupler to the flange and it comes right off. Remove the old transmission mounts, too.With nearly 150,000 miles on it, the coupler was dry and cracked. Yuck.When we got the driveshaft secured in the vice, we found that the rubber isolator in the carrier bearing had split from the housing. Good thing we had already planned on replacing it.There’s an 18 mm bolt behind the U-Joint that holds the two pieces of the driveshaft together. It’s easy enough to remove and replace with a box wrench.You can use a drift pin and a hammer and gently tap around the perimeter of the bearing to knock it off the front of the rear driveshaft. It’ll take about 10 minutes to work it off. Penetrating lube is helpful, here, too.Tap the new carrier bearing in place by tapping it gently around the circumference of the inner race. Be careful not to tap on the rubber portion of the sealed bearing.Reattach the 18 mm bolt to conjoin the front and rear driveshafts and it’s ready to go back in, but not before we do a few more jobs. You know, while we’re in there.The transmission mounts go on one way. Note the indentation in the bottom of the mount and the tab on the cross member.
For this job, I purchased the parts from ECS Tuning in Wadsworth, Ohio. The company offers lots of kits and suggested items, which are helpful to getting the most out of repairs. Look for a story on installing shifter bushings in an upcoming issue of Speed News.
