Gears *** speed sensor???
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,037
Likes: 28
From: Montclair New Jersey
Gears *** speed sensor???
I haven't decided which gear ratio I am going with either a 3.07 or 3.54. I know I have to change the drive gear and the driven gear in the trans to correct the speedometer but; do I also need a new speed sensor?? I have a 1986 auto with 275/40/18 all around.
thanks....
thanks....
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Because the speedo driven gear size changes to suit the rear ratio;
the factory used 2 VSS with different offsets to accommodate the difference
One did 35 -39 tooth driven gear ;
the other 40 -45.This one in no longer available new.
Many claim to have successfully used the lower one for higher gears by rotating it 180 degrees to change the offset.
( need to mod hold down VSS clamp
the factory used 2 VSS with different offsets to accommodate the difference
One did 35 -39 tooth driven gear ;
the other 40 -45.This one in no longer available new.
Many claim to have successfully used the lower one for higher gears by rotating it 180 degrees to change the offset.
( need to mod hold down VSS clamp
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,037
Likes: 28
From: Montclair New Jersey
I was told to get GM part# 25007308. That part is available for $125. Is this right information?? How far off would the speedometer be if I left the stock speed sensor?
thanks.
thanks.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
With the right speedo gears it will read correct
Problem is to do with the gear engagement .
The 40/42 tooth driven gear you require for 3.07 rear is larger than the 35 tooth 2.59 gear
you will be taking out and you are using the same 17 tooth drive gear
so the center line of the VSS has to be moved to accommodate the larger gear.
May work for a time but theory says it will be too tight and will strip one or both gears out
PM WVZR-1 ;
he is the speedo gear guru
