Transmission / Shifter clicking in 1st

[fiveseven808]

Hey guys,

My e24's been absolutely trouble free for the past few months... but recently, ONLY under hard acceleration and ONLY in first gear, I get this strange clicking noise coming directly from the transmission. If I rest my hand on the shifter, I can feel the clicking and the shifter wobbles side to side. It seems to occur at all RPM under hard acceleration. On smooth and light acceleration, I can't replicate the clicking noise, no matter how high I go, all the way up to redline.

This noise and feeling is very different from a bad CSB. It's definitely coming from around the transmission area somehow. In any other gear, no matter how hard I push the car, I get no strange clicking noise or transmission vibration.

Any ideas? If I could avoid replacing the transmission, that would be idea.

[alpinacsi]

Check the guibo

[fiveseven808]

I replaced the guibo, CSB and driveshaft within 9k miles. Can the guibo go bad that quickly?

[CW6er]

Does your guibo have the Dust cover/Vibration Damper? It may be loose and hitting the shifter. Do you have a short shift kit? They can hit also.

Did you replace the center bush in the Guibo?

The rear transmission mounts might be bad also. Check out this thread:
http://bigcoupe.com/phpBB2/viewtopic.php?t=10024&

[fiveseven808]

Does your guibo have the Dust cover/Vibration Damper? It may be loose and hitting the shifter. Do you have a short shift kit? They can hit also.

Did you replace the center bush in the Guibo?

The rear transmission mounts might be bad also. Check out this thread:
http://bigcoupe.com/phpBB2/viewtopic.php?t=10024&

I hoped to god that you were right, but the guibo hitting the shifter unfortunately wasn't the case (I don't have a dust cover). I replaced the shifter plate bushings and screws and loctited them all when I got the car.

I don't believe I have a short shift kit... how can I tell? the PO but some kind of weird blue non-stock looking shifter in there... Don't know what stock height looks like, so I can't say, but it's not terribly short.

What do you mean by the center bushing in the guibo? You mean the driveshaft center support bushing? That's been replaced.

Hmm.. I never thought about the rear transmission mounts being bad... The one on the left hand side looks a little smushed and noticeably smaller than the one on the right hand side... Could that be it?

Thanks for all the suggestions!

[CW6er]

I don't believe I have a short shift kit... how can I tell? the PO but some kind of weird blue non-stock looking shifter in there... Don't know what stock height looks like, so I can't say, but it's not terribly short.

Actually, the length of the shaft underneath the console is longer on a SS kit then standard. The height of the shifter above the console is generally the same. Here is a link on SS kits:
http://bigcoupe.com/phpBB2/viewtopic.php?t=6447&

Below is a photo of the different BMW OEM shifters generally used to "roll your own" SS kits. You can see that the longest one in the middle would be the shortest throw.

Since the Shifter (short or not) has been in there a while and the ticking only started recently, the fact that it might be a SS kit is probably not the problem

http://www.rongineer.com/Photos/shifter.jpg


What do you mean by the center bushing in the guibo? You mean the driveshaft center support bushing? That's been replaced.

#1 is the Centering sleeve that centers the shaft on the transmission output flange spigot.

Did you make sure that if the guibo had arrows molded into the rubber on the sides**, that they pointed to the flange faces?

Did you make sure that you only torqued the nut/bolt head that was bearing on the flange face and hold still the nut/bolt head that was bearing on the guibo?

If the guibo is on backwards or if the rubber was torqued into a twist, I guess the guibo could fail early?

** Not all have the arrows. There is an early and later style guibo and I forget which has the arrows.

http://www.realoem.com/bmw/diagrams/l/z/6.png



Hmm.. I never thought about the rear transmission mounts being bad... The one on the left hand side looks a little smushed and noticeably smaller than the one on the right hand side... Could that be it?

Yes, a soft mount may be letting the transmission rise under hard torque and hit the shift linkage. A SS kit would just mean that the mount wouldn't have to be as bad to allow interference because of the smaller clearance.

Check the front motor mounts also.

[fiveseven808]

Changed one transmission mount (drivers side) since it was the squishiest and the other one had threading issues. Shifting became 100% easier, but clicking started to happen in all gears under hard acceleration. Guibo looks a little funny, and there is definitely some rubbing going on between the guibo and the shift linkage.

-------------------

Replaced the other transmission mount today (with new undamaged one). Shifting is 100% better than last time again!!! Haven't taken the car out (it's late and the wife has other priorities for me). Even with the two new transmission mounts in, the driver's side one looks torqued/squished a bit and I can't figure out what is causing it... any ideas?
http://i62.tinypic.com/2us98ox.jpg

Removed heatshield and checked CSB. it looks like the outside layer is flaking a bit (due to heat?) but there are no cracks, and does not look damaged.
http://i57.tinypic.com/j6lg6s.jpg

http://i59.tinypic.com/w6z1nc.jpg

Pictures to come after they get off of my phone.


Edit: Added pictures... also, while looking at the online E24 manual, I've discovered my guibo has been installed backwards... f**k... Do I need a new one, or can I just reinstall it correctly?
http://i59.tinypic.com/ejdber.jpg

[fiveseven808]

Update:
Guibo was replaced a few hundred miles ago, and that solved everything. I have pictures of the old guibo's self destruction

EXCEPT, now it sounds like my car is eating the guibo again... CSB looked fine when I replaced the eaten guibo (it was brand new with the driveshaft a few thousand miles back).

Transmission mounts are new, engine mounts don't seem to move at all when the engine is revved.


Any ideas?

[carsnplanes]

Update:
Guibo was replaced a few hundred miles ago, and that solved everything. I have pictures of the old guibo's self destruction

EXCEPT, now it sounds like my car is eating the guibo again... CSB looked fine when I replaced the eaten guibo (it was brand new with the driveshaft a few thousand miles back).

Transmission mounts are new, engine mounts don't seem to move at all when the engine is revved.


Any ideas?

I could be wrong but I thought the guibo bolts, three of the six need to be facing the towards the rear and three towards the front. This I thought was to clear the rear of the tranny from the spinning bolts. Again, have to look at a picture to be sure of which three I'm thinking of. Yours are all facing forward and the threaded ends may be too close to the tranny and touching while spinning.

[fiveseven808]

I don't know about any other transmission configurations but it is impossible for the bolts to be inserted from the transmission side on my car. There is not enough clearance between the flange and the end of the transmission to slide a bolt in.

[carsnplanes]

I don't know about any other transmission configurations but it is impossible for the bolts to be inserted from the transmission side on my car. There is not enough clearance between the flange and the end of the transmission to slide a bolt in.

There is a certain spot that you can. Again, going from memory as I did a tranny auto to manual swap a few years ago.

[CW6er]

Carsnplanes is right about the bolts, but it is not because of clearance.

Look at your photo's above. The 3 drive shaft ears should have the nuts bearing against them, not the bolt heads. The idea is that head of the bolt bears against the rubber guibo and is held still while tightening the nut against the ears of the tranny/driveshaft. This way the nut won't twist the rubber in the guibo while it is being tightened if the bolt is in the other way around.You can look this up in the Manual:
http://www.malloc.nl/BMW/635CSi/pages/en/26110510.html#refertoc
(Workshop Manual - Replacing the Guibo)
I don't know how critical this is though. I've seen other people install the bolts wrong, but I don't know if they get away with it or if the life of the guibo is shortened? If you read the manual, at the very end showing the newer guibo (there are 2 types), it shows an illustration with the bolts installed as you have them and in the text above further up from it, they imply that you can hold the nut that bears against the rubber guibo still and tighten the bolt head on the ears. You might try loosening the bolts and re-torquing them using this method?