speedometer drive gear

C

chris varming

Member
Gentlemen, I have problems with my speedometer, that does not work. I have rebuilt a P6 over the last two years. The other day I had my first drive in it and everything went as expected. However, the speedometer did not work at all. I then changed speedometer, and cable and angle drive but still no good.
I had a look at the gear box itself (BW65) and found that the drive pinion does not engage with the speedometer drive gear, in fact 4 different drive pinions were tried with the same negative result.
I had a closer look at the drive gear on the shaft and found that the drive pinions all fitted perfectly in a spare gearbox (also BW65).
Comparing the drive gears through the whole made for the pinion housing, the teeth on the gears were going in different directions (top left to bottom right) and (top right to bottom left) and I wonder if the syncromesh gear on the P6 has been given a wrong gear?.
The obvious solution would be to remove the engine and gear box on the P6 and change the rear extension housing from the spare BW65, then the drive will fit the drive gear, but can anyone come up with a more simple solution? - I hope I have explained my dilemma sufficiently, and would be grateful if you could give me some advice, as a BW automatic is = a black box for me. regards, Chris Varming
 
You can remove the tailshaft housing without the need to remove the gearbox.

Just based on what you've said all I could think is that someone has fitted an SD1 BW65 and changed the tailshaft housing, but not changed the speedo drive gear as well.
 
harveyp6 said:
You can remove the tailshaft housing without the need to remove the gearbox.

Just based on what you've said all I could think is that someone has fitted an SD1 BW65 and changed the tailshaft housing, but not changed the speedo drive gear as well.
Click to expand...

Bang on the money Harvey.
Unfortunately the drive gears are not a straight forward swap, as the internal diameter of the gear is different.
You can however machine the drive gear from P6B to fit the SD1 output shaft.
The other option is a total strip of the box, and change the output shaft.
Also worth checking the length of the propshaft flange bolt, as the SD1 shaft is shorter, so the bolt needs to be longer.
 
Thanks for your reply - I'll go for the option to have the P6 drive gear machined to fit on the shaft of the SD1 BW and I'm ashamed to confess that the "someone" who forgot to change the speedo drive gear 2 years ago - was in fact me... :oops: regards, Chris Varming
 
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