Moparts Tech Archive
Speedo Gear ChangeRR4406PK
From: Dayton, Oh
Registered: Dec 2001
Will I need to drain the trans in order to change the speedo gear ?
No, you'll only lose a little bit of fluid. Jack it as high as reasonably possible in the rear, and have a catch pan ready, just in case.
Don't bother to drain the trans. Just jack the rear of the car up as high as you can, support it with jack stands and pull the speedo gear adapter out. You will lose very little or no fluid this way
Make sure that you index the new gear proerly or it either won't read or will chew up the plastic gear. Depending on if you have it in too close or too far off the shaft drive.
What do you mean by "Index the new gear"??
All great replies so far. The housing has an O-Ring seal. Some fluid will leak out, but not much if you raise the rear of the car.
Depending on the number of teeth, there is a range setting and the index marks corresponding to the number of teeth must be lined-up with the arrowhead.
Also, I noticed that sometimes the gear-carrier/adapters can be different.
I once had to salvage a different adapter off another trans to allow the gear-tooth count gear I intended to use.
Once you get to that area, you'll see the adaptor is marked for the different gear teeth. It's pretty easy to see it if it's clean. Index accordingly
The most common speedo pinion adapter with the various positions highlighted.
You rotate the pinion adapter until the tooth range you're using is at the 6 o'clock position, as shown in the attached image.