speedo and shifting

[dcmorgan2004]

ok so my speedometer stopped working, and apparently I lost my overdrive at the same time. so I'm at a loss, don't know what I should check first. any suggestions would be appreciated.

1990 ranger 2wd 4cyl a4ld.

 

[RonD]

1990 ranger used speedometer cable and a VSS(vehicle speed sensor) on the same unit at the transmission.

That would be where to start

A look here at what it looks like: http://www.therangerstation.com/tech_library/speedometer.shtml

3rd and 4th picture down

Could have a driven gear problem, gear attached to above unit, or it may be the drive gear inside transmission.

Speedometer of course uses the speedo cable

Computer controls Torque converter lock up(TCC) and OD(3-4 shift) in a 1990 A4LD transmission, and it uses Speed for that, which comes from the VSS

So I would start at the source for both, the transmission unit, it is on the tail shaft drivers side

Worse case is the Drive gear on tail shaft has failed, which can happen but less likely

Pictures here of what that setup looks like: http://www.explorerforum.com/forums/index.php?threads/88-to-94-a4ld-tranny-swap-issue.218721/

About half way down are the pictures
Drive gear is held in place by a ball on the shaft

Tail shaft housing can be removed to replace worm gear, just some bolts, not a huge project