speedo drive

Anonymous · Post by **Anonymous** » Tue May 23, 06 3:30 pm

since owning the car the speedo has never worked , coz i saw a reciept for some work in that area, i always assumed it was the speedo head that was busted, and was very wary of removing the exploding plastic dash, today after changing the oil and checking for trans leaks, i decided to investigate further, the cable is not snapped, it's lubed up and turns ok, put the cable inner into the s/head turned it and the needle moved

pleased coz now i know head is ok, the next part i would suspect, is the speedo pinion am i correct? i can get a hold of the part where the cable goes in and it just spins around and it dont feel like its connected to any thing, i would have thought this would not move as the pinion engages the worm gear on the output shaft, unless the worm gear is stripped? also the one i really want to know is if i pull the pinion adaptor out of the casing will i get a flood of trans oil out from there or will i be able to pull it and do the job in situ? thanks for any info, trev

Anonymous · Post by **Anonymous** » Tue May 23, 06 4:04 pm

Trev, I believe you will get a couple of litres of fluid in your face if you just pull it out, so be ready with a container

I`ll be changing mine soon if or when my wheels ever turn up

Dave-R · Post by **Dave-R** » Tue May 23, 06 4:19 pm

Trev. The bit that holds the speedo drive gear is built into a cam. The gears are different diameters for different rear gears. The drive gear housing needs to be turned so that the gear engages in the output shaft teeth.
There are numbers stamped on the housing to indicate where to turn it to for each gear you fit.

Dave-R · Post by **Dave-R** » Tue May 23, 06 4:23 pm

Look at the photo and you can see the tooth numbers stamped around the housing. You line these up with a mark that you will find in the trans.

Guy · Post by **Guy** » Tue May 23, 06 4:34 pm

here are the different colours and number of teeth

tooth colour

24 WHITE
25 BLUE
26 RED
27 WHITE
28 BLUE
29 BLACK
30 YELLOW
31 GREEN
32 BLACK
33 YELLOW
34 GREEN
35 ORANGE
36 RED
37 WHITE
38 BLUE
39 GREEN
40 ORANGE
41 RED
42 WHITE
43 BLUE
44 BLACK
45 Yellow

All available from Cope Racing Transmissions CTR for $20.00 http://www.coperacingtrans.com/transmissions.htm

Anonymous · Post by **Anonymous** » Tue May 23, 06 4:44 pm

ok cheers guys, dave im i right in understanding if this is in the wrong position whith the wrong pinion it wont work?

acording to the web site i need partnumber 2538933 but on the listings that number is not there?

Dave-R · Post by **Dave-R** » Tue May 23, 06 4:45 pm

Or if you are getting anything from Year One anyway you can stick one on the order from there.

http://www.yearone.com/serverfiles/head ... =117AA5042

Dave-R · Post by **Dave-R** » Tue May 23, 06 4:46 pm

It needs to be adjusted to engage and because you have changed rear gears it is probably the wrong gear anyway.

Use this to work out how many teeth you need on the gear. Just enter your tyre size and rear end ratio. You do need Microsoft Excel on your PC though.

http://challenger.mpoli.fi/web/AUTOMATICchart.xls

Anonymous · Post by **Anonymous** » Tue May 23, 06 5:12 pm

dave, dont have excel unfortunately, tyre size 27" 3:55 if you could look at it for me when you get a chance i would appreciate it thanks, T

Dave-R · Post by **Dave-R** » Tue May 23, 06 5:18 pm

Trev. When I said tyre size I meant like 235/70/14 which I think is the tyre size you run? That works out as 27 inches anyway. You need a 34 or 35 tooth gear.

Anonymous · Post by **Anonymous** » Tue May 23, 06 5:29 pm

hi dave 275/60/15 are my rear tyres.

turned it to the right numbers on the adaptor and!

whoohoo! for the first time since i got the car, my speedo works!

doctor dodge does it again cheers dave

Dave-R · Post by **Dave-R** » Tue May 23, 06 6:04 pm

Trev wrote:hi dave 275/60/15 are my rear tyres.

Well then they are 28 inches tall and you need a yellow 33 tooth drive gear for the speedo.