Speedo problems

[Bearindabush]

So, I found this when I pulled the speedo drive chasing a non working speedo. Anyone seen this before? I got a repacement which was different, which made the speedo move but not properly, eg; speedo still increasing while slowing. Any thoughts?? '94 TD27 4X4

 

[tweak'e]

i would test the output.
not sure if its a pulsed output or voltage. but most likely you will get a voltage reading and that should go up as you drive. if it goes down as you go down in speed then its most likely instrument issue.
if its goes unsteady then i would guess the speedo drive gear is loose on the main shaft.
i don't have the d21 book but i suspect its similar to the early td27 d22's.

 

[izzibri@gmail.com]

is it worth pulling out new one to see if the gears are matching ,you would see exessive wear imediately. could there be plastic stuck in the internal gear box drive

 

[Bearindabush]

Thanks for the input guys, so, an update, I've changed the dash cluster to one that is supposedly good and I've driven about 30km. The speedo seems to work but it's showing just over double the speed. I pulled the speed sensor and it looks good. Now, when I got this vehicle, the wires to the 4wd and nuetral switches on the transfer case were disconnected so I got an auto electrician to connect them up, still no warning light for 4WD? Could the error in the speedo reading be caused by the electrics thinking it's in low range?

 

[tweak'e]

Could the error in the speedo reading be caused by the electrics thinking it's in low range?

no. the sensor is on the output shaft after the low range. makes no difference if in high or low.
sounds like you have got a different speedo and sensor combo.

might pay to ID the gearbox and transfer in case you have one out of something else eg terrano etc.

 

[Bearindabush]

sounds like you have got a different speedo and sensor combo.
Thanks mate, that's been my thought all along, the supplier sent a different sensor