5spd swap rookie mistake

[boxy02]

Well, I thought I'd buy a 4-bolt shortened drive shaft in anticipation of installing my 5spd. I have a 4-bolt trans flange that I was going to swap into my gearbox...until I saw that the rear shaft splines weren't the same.

 

So, what now? Do I sell the 4-bolt shaft and get a 3-bolt or is there a 4-bolt trans flange out there with fine splines? 

Thanks in advance

Edited February 20, 2017 by boxy02

[halboyles]

The coarse splined flange is from early '02s,  Any later '02 4-speed would have the fine splined flange you need.  

[boxy02]

Thanks halboyles, that's good news!

[stephers]

Rogers tii has the fine spline flange's for sale new as well

[TobyB]

...it's been a while, but I have a vague recollection of the 4- speed fine spline being different than the 5- speed fine spline.

 

I have a firmer recollection of a very old thread about this subject.

 

I am positive that the 3 and 4 bolt 5- speed flanges interchange.

 

I am convinced that the 3- bolt guibo is thinner.

 

I am now going for a bike ride, as every BMW that we own is currently not working.

 

heh

 

t

 

[Mike Self]

From experience, the fine spline output flange is better than the coarse spline.  I had a coarse spline flange fail on my '73, when the car had less than 60k miles on it.  When removed, the "teeth" on the flange's inner ring were completely gone.  IIRC it was due to poor torquing of the flange retaining nut at the factory and/or a poorly heat-treated batch of flanges.  Bottom line was they had to replace the tranny output shaft as well as the flange with a fine thread setup.  No problems after that.  

 

Again, IIRC the changeover from coarse to fine was made in early January 1974.  

 

cheers

mike