2 years later...another guibo ready for replacement

[M3M3]

it is the goal of why driveshaft alignment is done. many threads describe the several ways to do this.

[bnam]

Is the distance between the output flange and the mounting ear on the back of the gearbox exactly the same for the 3 gearboxes (4spd, 5CR and 5OD)?

My thought is that IF they were the same distance apart and if the engine GB/DS were all tilted at a slight angle (exaggeraged above), then the mount on the 5CR would need to be LOWER not higher than the 4spd.

If the metric for the 5CR is higher (at 80mm) -- could it be because the relative distance between the mounting ear and output flange is different for the 5CR vs the 4spd? And, how does the 5OD compare to the other 2.

Or, have I got it all wrong?

Byas

[mattdanchris]

I just did a 5 speed conversion with the 240 trans. I had the same problem with trying to get the trans higher in the tunnel (I did use a hammer, but it seemed the metal was getting thin, so I stopped). I could get the guibo square to the output shaft by lowering the CB, but then the diff was too high and the 2 drive shafts were not straight. I ended doing a compromise. There is about 1 mm gap when the bolts for the guibo are loose (at the bottom) and the CB is 2 washers lower. Would it be better to close the gap on the guibo by lowering the CB more , making the 2 drive shaft angle worse, or leave it as is (both a bit off)? The car runs fine now, no vibration.

After reading this whole post several times, I have a question. Is guibo failure a problem with the 4 speeds? If not, why? It appears that the trans center mount is all over the place on these cars (80mm, 75mm, etc). We are trying to align everything perfectly and the factory did not. But we are having guibo failure.???

Last thought. If the trans too low is the problem, is there a way to lower the diff? In that case the trans, CB, and diff could all be a bit lower and be aligned.

Carl

[BillWilliams]

I think you will have a giubo failure within 5k miles if you have that gap between the flange and giubo.

[ShakeyC]

Looking at your guibo to me its overall outer diameter seems bit much relative to the bolt holes? I say this because on your gear leaver platform where its mounts to top of the gearbox itself is where your rubbing marks against right hand side is shaving your guibo.

How does your centre prop coupling look? if that too is stating to crack and wear then i be inclined to suggest poor alignment and try using m40/m42 gearbox mount to stop the whole drivetrain rotating/skewing right under acceleration.

[jgerock]

My 6-hole febi/Bilstein guibo measures:

111 mm O.D. (outside diameter)

39 mm I.D. (inside diameter)

78 mm diameter bolt circle

28.25 mm thick at each bolt location

16.5 mm thick at the webs (between the bolt locations)

Looking back at my notes, the original 4-speed driveshaft measured 63" overall, I ordered a 59.75" long driveshaft and received one that was 59.375" long. I have left a message for DLS in Portland but haven't heard back from them. When they call back, I'm going to ask them about the washers I have installed and for their professional advice on my situation.

I have thoroughly enjoyed having an overdrive transmission in my car and like the reduced cruising RPM's on long drives and the ability to hear my stereo, but my next 2002 will retain the stock 4-speed tranny.

[mike472]

I am in the same boat with my 5 speed driveshaft being too short by about 5 washers. That was the amount it took to take the distortion out of the guibo. Now the bolts are too short. I had it in another car and swapped it over but somehow it didnt fit the same. I think the guy who did my last conversion moved things around to make it fit. I too experienced all the things already mentioned here when trying to align the driveshaft to the rear end. I shimmed the transmission up and down experimenting with different heights and looking around at clearances between driveshaft and shift platform and other things like the exhaust and transmission case. I have IE shift platform which mounts with a rubber nipple sticking down from the rear mount bolted to the tunnel. This started to rub on the driveshaft when I jacked the trans up too high. I have three washers at the center bearing to get the twist out of the guibo. Besides the shift platform hitting I can't get any higher because the headpipe is starting to touch the firewall as well as hitting underneath the car. When I push the trans up any further I can feel the shifting get hard because the platform is starting to distort. I have a piece of foam rubber on top of the shifter platform that IE supplies to quell any vibration or rattling against the tunnel. This was pressed firmly against the tunnel to get any kind of decent alignment on the driveshaft.

To solve the short driveshaft problem I was thinking about making a spacer ring to put on one side of the guibo. I am pretty sure the pilot bearing will still be engaged with the nipple on the output flange. I don't know how long that nipple is but I have to take the driveshaft down anyway. The alternative is welding in a chunk that measures about 3/8" into my driveshaft which would really suck. Besides paying to do a job over again I hate trying to get at those bolts on the back of the driveshaft.

[bmwmalcolm]

mike472- what about machining a spacer ring for the diff end of the DS, to go between the flanges longer studs would be needed but at least the guibo would be unaltered. you would have to check if the center bearing position adjustment would allow the rear section to be that far forward.

[mike472]

Not a bad idea. Just have to make a longer set of those half moon bolts by grinding the side off a hex bolt. I think those are 10.9's. The spacer has to be accurately made so it aligns perfectly and does not cause any misalignment. I have to look at the flange of an old driveshaft tomorrow to see how I can make a suitable spacer.

[ShakeyC]

I crawled under my car today and my Febi guibo has the same dimensions as you listed below however i can easily fit a finger all the way around the guibo in particular between guibo and gear lever platform.

As our guibo's the same and your pictures show rubbing against the platform where its mounted onto the gearbox i say your issue is there (guibo being the other possibility which we can now rule out)

big hammer to widen the tunnel, my mounts ended higher than standard 02 mounts as you can see. I did NOT measure 80mm BUT used 2 easy methods (3x set squares, meter ruler and something straight) to measure middle of align output flange to middle of input flange on diff then mounted to suit in line.

Prop shaft alignment once fitted

reversed view, not ample space around guibo, the guibo face is inline with hex cap bolts fixing the gear leaver platform

May i suggest loosen the 2x hex cap bolts securing platform to gearbox, put your guibo in then adjust (rotate the platform anti-clockwise) a touch to increase clearance where your guibo is being shaved then nip them up. Sometimes if the rubber inside the little mounts are worn dropping the platform right where you don't need it too.

Due to handmade nature of old cars no 2 measurements are the same, for propshaft length needs to be shorter on front half appox the length of the overdrive part of gearbx casing which is roughly 90mm.

Washers are ok to use on the bolt head side please ensure you use same thickness washers for all 6 holes otherwise you have high rpm vibrations and when you back off the throttle from high rpm

My 6-hole febi/Bilstein guibo measures:

111 mm O.D. (outside diameter)

39 mm I.D. (inside diameter)

78 mm diameter bolt circle

28.25 mm thick at each bolt location

16.5 mm thick at the webs (between the bolt locations)

Looking back at my notes, the original 4-speed driveshaft measured 63" overall, I ordered a 59.75" long driveshaft and received one that was 59.375" long. I have left a message for DLS in Portland but haven't heard back from them. When they call back, I'm going to ask them about the washers I have installed and for their professional advice on my situation.

I have thoroughly enjoyed having an overdrive transmission in my car and like the reduced cruising RPM's on long drives and the ability to hear my stereo, but my next 2002 will retain the stock 4-speed tranny.

[jimk]

... Due to handmade nature of old cars no 2 measurements are the same, for propshaft length needs to be shorter on front half appox the length of the overdrive part of gearbx casing which is roughly 90mm.

I will never be convinced of the statement about "hand made". To think driveshafts are selected on the assembly line for length is just not rational. It's like you couldn't use another stock driveshaft with the 4 speed. A new driveshaft from the factory would fit in that instance.

If the distance between the front subframe and rear subframe have changed in service, the doors wouldn't even close on the car. The potential for error in measurement for a new driveshaft is a much greater than simply deducting the added length of trans + difference in thickness of the guibo (if changed out to a 3 bolt). For sure BMW has worked out the tolerance stackup and it is no greater than the adjustment holes in the diff. mount.

[ShakeyC]

If this was true we all would shorten the propshaft exact same amount, none of us would need to measure, none of us would have any issues?

Time is the enemy when new you could grab any part of the shelf and it fit, add few decades of wear and tear climates, useage ect they won't always be mm perfect fit moreso than a chassis welded assembled by robots.

[jgerock]

As a follow up to the guibo issues, with the bolt on tranny mounts and same febi/Bilstein guibo installed in 2012 is still in place.  This is after two AutoX sessions and a PDX at Summit Point.   Before any long trips I crawl under the car and do a close inspection.  No issues, no vibrations.

[PaulTWinterton]

I'm not a track guy, but I want to be at some point.

Obviously 02s would be my track car of choice. When I think about it I always think about the quibo being a weak link in the drivetrain. The punishment that little rubber connection suffers can't be good.

What experience and advice do race car owners have?

[Hans]

AS I recall, the tranny end of the drive shaft has a hole that fits over a pin on the output flange of the tranny. If this is prevented from seating fully by the washers, would that allow some play? Maybe use bigger diameter washers and slightly longer bolts.