I have a 1981 Volvo 245 GLT with 450 K+ miles.. but I am

having a problem. Recently, I lost my overdrive(OD)it died and replaced it

with a unit from a later model. However, now, my speed is being inflated as

I drive, e.g. 65 MPH is really 57 MPH and so on... Check with the guys at

the Volvo to ensure that I had the OD right gear to match up with my rear end gear. It is all correct.

Any suggestions? It is not only inflating my speed but also my miles.

/// The only thing that could do this is the gear for the speedometer. The mismatch you have between the speedometer and the OD unit must be the problem. Is the gear in the main transmission or the OD? It's in the OD right? It must be. Other wise the OD would read wrong every time you went from standart to OD.

When Volvo gave you the gear number did they understand that you had a later od OD?

Larry:

Thanks for your response. I did not inform the dealer that I had a later model OD however, it was my understanding that there was no difference in the units, i.e. the gearing is all the same. Plus the OD model number matched the rear-end that how we knew what gear to order.

Thanks

Train

Maybe you need to change the drive gear in the trans to the one out of

the old overdrive. If that is the only thing that you changed then that

is what's different now. I believe that you can change the gear from one

unit to another. The other thing may be that the speedo cable is bad and

is whipping around inside the cable housing? It sounds more likely to be

the drive gear to me.

Dave 82 242ti

Dave:

First thing I did when I realized there was a problem was replace the drive gear in the new one with the old one. They were the same. Turns out the gear that was in the OD was the wrong one. I will check the cable.

Thanks

Had a problem with my speedo-gear. Turned out that the bushing in the tail piece of the transmission was gone allowing the output shaft of the transmission to move excessively which eventually damaged the teeth on the plastic speedo-gear. I would suggest you check the play on the output shaft. It you can move the shaft up and down, or side to side, then you may have a problem. Relatively easy to repair, if you get it soon enough.

Wayne:

Thanks for your suggestion. I will check that first thing Monday. I will let you know.

Thanks

Train