Hey, folks. Yesterday I noticed something new that concerns me. There is a grumbling sensation in the chassis at low speeds. It goes away as speed increases, but if I slow back down, the grumbling comes back. It almost feels like it could be loose driveshaft bolts, but I checked everything today and it is all tight underneath. I also topped off my tranny and diff with fluid. They dripped very lightly when I pulled the plugs, so I believe they were full.
My fear is that the differential gear lash has gone awry, or (worst case) that the tranny is on its last legs.
Thoughts, personal experiences or feedback are appreciated.
Thanks.
Jose
Need help diagnosing a driveline problem
Moderators: GRNSHRK, ron, bfons
Need help diagnosing a driveline problem
1987 M6 - My dream car
Trans or diff internal issues usually seem to make more noise than anything (as opposed to a seat of the pants grumble).
Various mounts are easy fixes, so I'd go for them first.
You checked out half shafts and rear wheel bearings for play?
Various mounts are easy fixes, so I'd go for them first.
You checked out half shafts and rear wheel bearings for play?
79 Alpina B7 Turbo #096, 79 Alpina B7 Turbo #124, 80 635csi, 80 323i Baur
I had her up in the air yesterday (lift at work) and checked all those bolts. All down and tight. The one thing I couldn't get at was the center bearing, but that is a factory BMW part with less than 8K on it. Not impossible it is worn out, but unlikely.
I know there is a torn mount, so that is going to get ordered tonight. I will report if that helps.
Jose
I know there is a torn mount, so that is going to get ordered tonight. I will report if that helps.
Jose
1987 M6 - My dream car
I replaced the tranny mounts yesterday. One was torn in half, the other was bulged and starting to come loose. So they definitely needed to come out.
The problem has been lessened, but it still has some "rattle". I noticed some exhaust system shake today, when it contacted the body. I now wonder if the motor mounts don't need replacement as well. I will check that next.
Jose
The problem has been lessened, but it still has some "rattle". I noticed some exhaust system shake today, when it contacted the body. I now wonder if the motor mounts don't need replacement as well. I will check that next.
Jose
1987 M6 - My dream car
if the engine mounts go soft they tend to overstress the tranny mounts, so it is quite possible that the engine mounts are bad if the tranny mounts are torn.
BTW I recently noticed that an E23 has a different LH engine mount; as well as a support rubber, it has a separate tension element, presumably to counter engine/driveline torque in low gears.
It did cross my mind that something similar could be added to an E24 if mounts fail regularly otherwise.
cheers
BTW I recently noticed that an E23 has a different LH engine mount; as well as a support rubber, it has a separate tension element, presumably to counter engine/driveline torque in low gears.
It did cross my mind that something similar could be added to an E24 if mounts fail regularly otherwise.
cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I noticed a similar issue with both engine mounts went out on my 535i. Still having slight issues but haven't looked yet. I think it would be transmission mounts. If those are solid and replace, then I would look to the DS.
I also did have a guibo bolt come out once on 635. When this happened, I got an odd rumbling under the console (as everything was now way out of balance missing 1 of the 6 bolts).
I also did have a guibo bolt come out once on 635. When this happened, I got an odd rumbling under the console (as everything was now way out of balance missing 1 of the 6 bolts).
http://www.Drive4Corners.com
'79 635CSi Revival
'80 635CSi
'83 633CSi Callaway Turbo continued as 1988 535is Turbo
SOLD: '81 635CSi/A
'79 635CSi Revival
'80 635CSi
'83 633CSi Callaway Turbo continued as 1988 535is Turbo
SOLD: '81 635CSi/A
OK, so I finally tore into the underside of the M6 to address this issue and install new catalytic converters with the correct EO numbers.
I put the rear end on high stands and removed the exhaust and tunnel heat shield. Ever since I bought it, the driveshaft would make a clanging sound when I cycled the clutch (like in a drive through line). When I monkeyed around, I could actually feel slop in the center u-joint and could make that clanging sound by twisting the two halves in opposite directions. I could also clearly see that one of the bearing cups was completely blown open. I now think that center joint might have been on the way out for a while.
The u-joints are staked in and aren't repairable and since whole unit is dynamically balanced it's new driveshaft time. I did find a San Antonio based shop that looks like a good option. They also sell a 1 piece driveshaft, but I understand that if you go that route they can vibrate more. The 2 piece has worked fine, so I just want a high quality OEM equivalent part.
http://www.driveshaftspecialist.com/Imp ... l/BMW.html
I don't know of anyone local who rebuilds driveshafts. Any thoughts about the shop linked above? I'm ready to pull the trigger on a next day delivery.
Jose
I put the rear end on high stands and removed the exhaust and tunnel heat shield. Ever since I bought it, the driveshaft would make a clanging sound when I cycled the clutch (like in a drive through line). When I monkeyed around, I could actually feel slop in the center u-joint and could make that clanging sound by twisting the two halves in opposite directions. I could also clearly see that one of the bearing cups was completely blown open. I now think that center joint might have been on the way out for a while.
The u-joints are staked in and aren't repairable and since whole unit is dynamically balanced it's new driveshaft time. I did find a San Antonio based shop that looks like a good option. They also sell a 1 piece driveshaft, but I understand that if you go that route they can vibrate more. The 2 piece has worked fine, so I just want a high quality OEM equivalent part.
http://www.driveshaftspecialist.com/Imp ... l/BMW.html
I don't know of anyone local who rebuilds driveshafts. Any thoughts about the shop linked above? I'm ready to pull the trigger on a next day delivery.
Jose
1987 M6 - My dream car
You might be able to find a local shop specializing in driveshaft repair for trucks and other commercial vehicles. Along with my 635, I've got 3 Alfa Spiders, which have a very similar driveshaft setup, with the same giubo, center support bearing, and 2-piece shaft. There's a local shop here in Tampa that's done all my Alfa driveshaft work, including dynamic balancing, and the cost was also ridiculously less than any of the Italian/German specialty shops. IIRC, several years ago I paid ~$80 in labor for a complete driveshaft rebuild.
Called a few places and their answer led me to a specialty shop in Santa Rosa.
The driveline shop said they can't afford the $1 million machine that you need to do replacement on the BMW staked joints. He would just order out of a shop in Los Angeles for the same $400, but I have to take it all to them for exchange and it's at least two days. Sounds like the same shop I used to rebuild my 2002 driveshaft.
Well ..... looks like DriveShaft Specialist is a good option.
Jose
The driveline shop said they can't afford the $1 million machine that you need to do replacement on the BMW staked joints. He would just order out of a shop in Los Angeles for the same $400, but I have to take it all to them for exchange and it's at least two days. Sounds like the same shop I used to rebuild my 2002 driveshaft.
Well ..... looks like DriveShaft Specialist is a good option.
Jose
1987 M6 - My dream car
I ordered the driveshaft at around 11:00 yesterday morning and it was at my door by 10 am today. Shipping was $60 for next day. The part looks great and that is some seriously fast service. I will go install and report back.
Update: Turns out, they swapped my order and I got someone else's. Waiting on the right one.
Jose
Update: Turns out, they swapped my order and I got someone else's. Waiting on the right one.
Jose
1987 M6 - My dream car
I actually received the correct driveshaft the next day (11/12) and return shipping slips for my core and the incorrect shipment.
The driveshaft shipped ready to install with new center nut/packing, center bearing and guide bushing at the front.
Unfortunately, I had all my wisdom teeth pulled yesterday and I can't take advantage of the dry weather to put in the driveshaft or continue working on the exhaust ..... -sigh-
Jose
The driveshaft shipped ready to install with new center nut/packing, center bearing and guide bushing at the front.
Unfortunately, I had all my wisdom teeth pulled yesterday and I can't take advantage of the dry weather to put in the driveshaft or continue working on the exhaust ..... -sigh-
Jose
1987 M6 - My dream car
No hanky, but I am definitely taking a butt kicking Greg. 
The dentist said day 3 and 4 is going to be the worst. He wasn't kidding.
I didn't go with the SR shop because they don't rebuild in-house, they said it would take two days to get it and I had to go to SR to make the exchange.
Driveline specialist does the work in-house and they could next day for $60, although regular 4-day delivery is included in the $400 price tag and they warranty the same as OEM. Turns out I didn't need to spend on the next day delivery. That's a bit of a bummer.
Jose
The dentist said day 3 and 4 is going to be the worst. He wasn't kidding.I didn't go with the SR shop because they don't rebuild in-house, they said it would take two days to get it and I had to go to SR to make the exchange.
Driveline specialist does the work in-house and they could next day for $60, although regular 4-day delivery is included in the $400 price tag and they warranty the same as OEM. Turns out I didn't need to spend on the next day delivery. That's a bit of a bummer.
Jose
1987 M6 - My dream car
Oh boy, oh boy, oh boy!!! My teeth are finally at a point where I can start doing some physical work and in the time I was waiting I have received some goodies.
I got a UUC DSSR for my shifter and I ordered a new SS spiral flow muffler. Now I just need to order a couple pieces of 45 degree 3" tubing and I will be able to weld up a 100% SS exhaust for the old girl.
I am supposed to have good weather this weekend too. Woohoo!!!
Jose
I got a UUC DSSR for my shifter and I ordered a new SS spiral flow muffler. Now I just need to order a couple pieces of 45 degree 3" tubing and I will be able to weld up a 100% SS exhaust for the old girl.
I am supposed to have good weather this weekend too. Woohoo!!!
Jose
1987 M6 - My dream car
Work update for today.
I got the DSSR installed and it was not super hard, but had its challenges. First off, somebody on mye28 said they installed a DSSR without removing the driveshaft. I do not see any way to install that thing on an M6 with the driveshaft in place.
The DSSR uses a different shifter coupling that is not offset like the OEM part. You need to order that new coupling along with the DSSR. I also had to remove the guibo to get access to the shifter coupling. Removing the old coupling was not so bad, but installing the new one was a BITCH! The new coupling still has the rubber washer insert to maintain tension and that is difficult to compress. Also, the retaining pin is a super close tolerance fit. That makes it difficult to insert all the way through. I was finally able to get everything installed with a little "persuasion" and I did not have to lower the transmission to do the job. The shifter still has movement when in gear, but it is definitely way tighter. I will give some feedback on function when I have it back on the road.
The driveshaft went right in with no unusual issues. Loosen the slide joint nut, compress the shaft, put the back end into the sub-frame space, slip the front end onto the transmission output shaft and then loosely mount the center bearing. Insert guibo bolts, slide the back half of the shaft into place, put on the rear flange nuts. Finish by torqueing the guibo bolts, then tension the center bearing and torque down, next is rear flange nuts and last is setting the slide joint nut to 7 ft/lb. The biggest drag was trying to torque down the guibo nuts to 83 ft/lb. lying on my back. MAN my arms and shoulders are sore.
Since I have to friggin smog this year, I also started in on the fabrication of yet another version of my exhaust. This time, it will be fitted with fully Ca. legal catalytics, so that means it should be the final iteration that will last the life of the car. I already replaced from the muffler back with SS, but I will still end up with one last section of aluminized pipe that I need to replace between the muffler and center section. I need to get the old girl back on the road asap, so replacing that last section of 3" pipe will have to wait for the dry, summer weather.
So far, I have only gotten through mocking up the catalytic section. The design is a dual pipe from the headers into an x-pipe fitted with an O2 bung. The new catalytics attach directly to the x-pipe and then a y-pipe pulls the dual 2" into the 3" SS Moroso spiral flow muffler I just bought. Ooooooh ........ shiny ........
Hopefully it stays dry tomorrow and I can finish tacking in all the loose pieces. It promises to be great fun laying on the ground and sending sparks flying on top of myself...again. I'm not sure if I'll have enough gas to finish all the welding, though. Wish me luck folks.
Jose
I got the DSSR installed and it was not super hard, but had its challenges. First off, somebody on mye28 said they installed a DSSR without removing the driveshaft. I do not see any way to install that thing on an M6 with the driveshaft in place.
The DSSR uses a different shifter coupling that is not offset like the OEM part. You need to order that new coupling along with the DSSR. I also had to remove the guibo to get access to the shifter coupling. Removing the old coupling was not so bad, but installing the new one was a BITCH! The new coupling still has the rubber washer insert to maintain tension and that is difficult to compress. Also, the retaining pin is a super close tolerance fit. That makes it difficult to insert all the way through. I was finally able to get everything installed with a little "persuasion" and I did not have to lower the transmission to do the job. The shifter still has movement when in gear, but it is definitely way tighter. I will give some feedback on function when I have it back on the road.
The driveshaft went right in with no unusual issues. Loosen the slide joint nut, compress the shaft, put the back end into the sub-frame space, slip the front end onto the transmission output shaft and then loosely mount the center bearing. Insert guibo bolts, slide the back half of the shaft into place, put on the rear flange nuts. Finish by torqueing the guibo bolts, then tension the center bearing and torque down, next is rear flange nuts and last is setting the slide joint nut to 7 ft/lb. The biggest drag was trying to torque down the guibo nuts to 83 ft/lb. lying on my back. MAN my arms and shoulders are sore.
Since I have to friggin smog this year, I also started in on the fabrication of yet another version of my exhaust. This time, it will be fitted with fully Ca. legal catalytics, so that means it should be the final iteration that will last the life of the car. I already replaced from the muffler back with SS, but I will still end up with one last section of aluminized pipe that I need to replace between the muffler and center section. I need to get the old girl back on the road asap, so replacing that last section of 3" pipe will have to wait for the dry, summer weather.
So far, I have only gotten through mocking up the catalytic section. The design is a dual pipe from the headers into an x-pipe fitted with an O2 bung. The new catalytics attach directly to the x-pipe and then a y-pipe pulls the dual 2" into the 3" SS Moroso spiral flow muffler I just bought. Ooooooh ........ shiny ........
Hopefully it stays dry tomorrow and I can finish tacking in all the loose pieces. It promises to be great fun laying on the ground and sending sparks flying on top of myself...again. I'm not sure if I'll have enough gas to finish all the welding, though. Wish me luck folks.
Jose
1987 M6 - My dream car
I think this is the final progress update for this project.
I finally got the exhaust system finished and drove the M6 to work for the first time in four weeks. There is a light rattle, but it goes away when I am under throttle. I think it's a clearance issue with the new exhaust.
The driveshaft seems to be working just fine with no rattles or oscillations through the shifter. That tells me there should be no clearance issues and I should be good to go with the new parts.
As to the DSSR, the shifter it feels WAY different. I already had a UUC shifter with the cartridge bearing, but the DSSR creates a much more positive, mechanical feel. I think you would get that same high feedback sensation even with a stock shifter. I highly recommend a UUC DSSR.
Jose
I finally got the exhaust system finished and drove the M6 to work for the first time in four weeks. There is a light rattle, but it goes away when I am under throttle. I think it's a clearance issue with the new exhaust.
The driveshaft seems to be working just fine with no rattles or oscillations through the shifter. That tells me there should be no clearance issues and I should be good to go with the new parts.
As to the DSSR, the shifter it feels WAY different. I already had a UUC shifter with the cartridge bearing, but the DSSR creates a much more positive, mechanical feel. I think you would get that same high feedback sensation even with a stock shifter. I highly recommend a UUC DSSR.
Jose
1987 M6 - My dream car