Car Forum World

It's a '90 Ranger S Cab, 2.9 L with and A4LD trans, and sat for two years with a wasted trans. I swapped the trans out for a reman A4LD, and all is swell except for the speedo. In the dash it now reads considerably faster than real mph, and past 65 mph the needle buries itself past 85, and real speed is close to 65. Needle motion is smooth. The original speedo drive had 17 teeth, and the substitute drive is the same. Cable and cable engagement looks to be good. Tire size and rear end ratios are stock no change out, and the speedo worked good before the trans failure. anybody have any ideas?

Part two my factory tach intermittantly will read approx 500 1000 rpm higher than average 700 rpm at idle norm, showing 1200 at idle, then sometimes after returning to "idle", will function properly for awhile. My schematics don't show the factory tach. What circuit is the tach drive connected into, and do I possibly have a bad ground or dash buffer? I am stumped..

Had the same thing happen on an '88 Ranger with the same engine. Turned out to be the OSS.Output Speed Sensor switch on the transmission. 'Bout a $15, five minute fix.

As far as the speedo, a tranny place will have to install the propper reduction gear at the cable input to the tranny.
$60.00 +/

Tach? most likely a loose ground, or power wire. tough to diagnose.