Noisy ZF / transmission options

[coupe2800cs]

old thread on the 5 speed https://e9coupe.com/forum/threads/alpina-csl-5-speed-gearbox-zf-s5-18-3-schnitzer-gs-koepchen.27673/

, there was guy in Ireland that does ZF gear boxes, think I recall reading about parts to make a 4 speed into a 5 speed on his website...

 

[coupe2800cs]

today I drove the Taiga for 350 miles. It has the ultra rare ZF 5 speed box, with 1:1 on 5th, mated to a 3,64 diff. The engine is a heavily modified 3,5 with mapped ignition and modern FI. Has 365 hp and 420Nm of torque,
The box was rebuilt by a ZF specialist in Kassel, Germany. It is inherently noisy!. Very nice to operate, and a long lever.
i also have a NOS 4 speed ZF, with matching prop shaft with smaller screws. I might use it in the very early 2800 CS that my father bought used in 1971. I have heard that BMW changed to Getrag because they were cheaper, but donˋt know if itś true

Was curious if the ZF 4 speed driveshaft is different on Coupes than those with 262? I have a early 2800cs has the ZF 4 speed, I have a extra driveshaft from a E12 in the event I need it in the swap I'm doing to a 262 box.

 

[coupe2800cs]

ZF 18-3 - 5 Speed Dog Engagement Gearbox - Elite Racing Transmissions

Elite Racing Transmissions offer for sale complete ZF S5 18-3 Historic gearboxes which are a direct replacement for the original ZF gearbox. They are completely new, with all parts being manufactured by ourselves in house. Parts can be interchanged with the original gearbox, you can also buy...

eliteracingtransmissions.com

 

[Markos]

ZF 18-3 - 5 Speed Dog Engagement Gearbox - Elite Racing Transmissions

Elite Racing Transmissions offer for sale complete ZF S5 18-3 Historic gearboxes which are a direct replacement for the original ZF gearbox. They are completely new, with all parts being manufactured by ourselves in house. Parts can be interchanged with the original gearbox, you can also buy...

eliteracingtransmissions.com

There is huge support for the S5-18/3. It is used in all kinds of period motorsport and there are numerous companies making custom gear sets. ZF makes and sells the cases and housings bits also. The only thing of value from a four speed ZF in making a 5spd is the first part of the case, and the bell housing. Most S5-18/3’s have six bolts between the bell housing and the case, but the BMW box only has four. You are still looking at at least $5K to make a 5spd, perhaps less if you pickup a complete set of old gears. As the site above mentions, you can’t mix newly designed gears with original ZF gears.

Also you see the link above that they mention dog engagement. They are selling dogleg shift patterns, and synchromesh or dog engagement. Also known as a dogbox.

If you are bored:

 

[coupe2800cs]

There is huge support for the S5-18/3. It is used in all kinds of period motorsport and there are numerous companies making custom gear sets. ZF makes and sells the cases and housings bits also. The only thing of value from a four speed ZF in making a 5spd is the first part of the case, and the bell housing. Most S5-18/3’s have six bolts between the bell housing and the case, but the BMW box only has four. You are still looking at at least $5K to make a 5spd, perhaps less if you pickup a complete set of old gears. As the site above mentions, you can’t mix newly designed gears with original ZF gears.

Also you see the link above that they mention dog engagement. They are selling dogleg shift patterns, and synchromesh or dog engagement. Also known as a dogbox.

If you are bored:

Race car dog box noisy ! Think there are few gear shops in Los Angeles, and in North Carolina that can make gears that will last a life time, even straight cut gears can be a real drag after so many miles, think they have a helical gear option?

 

[Dan Wood]

When we first bought the 2800CS there was what I thought a lot of transmission noise from the ZF transmission. After pulling the trans I found the pilot bearing was wrong and too large for the pilot shaft (pic attached). Hoping this may have caused the noise, a new clutch, throw out bearing, etc was installed. The noise is still there and reading this post it sounds "normal". The other possibility could be the wrong pilot bearing caused the front transmission bearing to wear.
In the 70s we did use STP as I also read in this post to quiet the rock crushers.
Is there any consensus on what fluid is recommended to quiet the beast? Thicker fluid, STP, witches brew?
While we can live with noise we certainly don't want total transmission failure.

 

[Dan Wood]

I am going to use 50/50 Redline MTL and Brad Penn Classic GL-4 80/90w gear oil
Thanks for the response I received.

 

[bmw2800cs]

La Jolla independent told me that parts are not available for the ZF - I have a 71 2800cs with a ZF. Another very prominent person in this forum said the parts are available in Germany. So what help am I? I guess I'm trying to say that you should verify if you can even get the parts before you go down the path of re-building it.