News:

It appears that the upgrade forces a login and many, many of you have forgotten your passwords and didn't set up any reminders. Contact me directly through helpmelogin@dodgecharger.com and I'll help sort it out.

Main Menu

Speedometer pinion problem?

Started by 1BAD68, April 03, 2010, 04:54:58 PM

Previous topic - Next topic

1BAD68

I replaced my speedo pinion with a 34 tooth gear in my 904 trans. I have 3:55 rear gears and run 25.5" tires.
Now my speedometer is about 10-15 mph off too fast.
I read that I would need around a 34-36 tooth gear and picked the 34 because I figure its better to register a little fast than slow but I thought it would be only 1-3 mph fast..
Am I missing something here?

John_Kunkel

The math says you need a 36.5 tooth pinion so either a 36 or 37 would work; I would go with a 36 because it will make it run a little fast...helps avoid speeding tickets.

BTW, the odometer is a better indicator of the correct pinion, a faulty speedo can be off even with the correct pinion.
Pardon me but my karma just ran over your dogma.

dspaulding70

Where is the best place to get a 34 tooth pinion gear for my transmission?

will

Cope Racing Transmissions has them.

Dino

Extraordinary claims require extraordinary evidence.

dspaulding70

for my 70 727, would i need the long one or short one?

Nacho-RT74

Venezuelan RT 74 400 4bbl, 727, 8.75 3.23 open. Now stroked with 440 crank and 3.55 SG. Here is the History and how is actually: http://www.dodgecharger.com/forum/index.php/topic,7603.0/all.html
http://www.dodgecharger.com/forum/index.php/topic,25060.0.html

Paul G

The speedometer can be way out of calibration. Like John said, use your odometer to verify you have the right pinion. Best way is to get on the highway and use mile markers to verify actual miles of travel vs. odometer miles of travel.
1972 Charger Topper Special, 360ci, 46RH OD trans, 8 3/4 sure grip with 3.91 gear, 14.93@92 mph.
1973 Charger Rallye, 4 speed, muscle rat. Whatever engine right now?

Mopars Unlimited of Arizona

http://www.moparsaz.com/#