right i've had the car a few months now and when i first got it the speedo bounced around alot, never really close to the accurate speed.

after removing the clocks, then the speedo cable, then the speedo drive i can still not get the thing to work at all! i can only think that the problem could lie in the gearbox in the form of a damaged nylon wheel that runs off the diff?

can anyone shed a little light on this for me as its now driving me crazy!! cheers.

 

Spin the cable by hand does the speedo work ?
I believe that they suffered form DIFF bearing wear that causes the speedo drive to gear to shag out.
tabetha

 

Try another speedo if you can, if that doesnt cure it then as said your gearbox is probably goosed

 

cheers for the replies guys, ill have a go with a new set of clocks but im not sure it'll work as when i spin the cable like you say the speedo moves.

i've had the clocks out and driven the car with them removed as so i can see if the actual cable is spinning but it doesn't, occasionally spins for a few seconds but then it stops again.

whats the best bet, gearbox rebuild or just get a new rst box. not sure i want to loose the lsd and get a 3i box?

thanks!

 

well if the cable doesnt spin constantly then the box must be at fault if you're sure the cable is ok?

Was the nylon drive gear worn?

 

not sure mate, i removed the speedo drive from the gearbox housing, the worm that spins but you cant actually inspect the nylon drive gear that runs off the diff unless you take the gearbox apart. fairly sure thats what its got to be though.

 

you can remove the nylon drive gear easily, theres a locking pin you have to remove and then it simply pulls out.........

 

nah mate thats the worm that pulls out, the actual nylon drive gear is attatched to the gearing inside the box. i think its the part in the box that has gone.

 

ohhhhhhhh do you mean the drive gear on the differential then?

 

yeah thats the one mate, think it may be seized or worn maybe even a broken tooth. the thing is they are like 10 quid to replace but it would mean stripping the gearbox to access it. might be easier and cheaper in the long run to just swap boxes?

 

Im sure they are metal as its a part if the differentials casting

 

no mate i can promise you that they are nylon, they cost £8.99, its just fitting the bloody thing. i had an old damaged RST box in the garage so i took it apart to see and the diff bearings were actually seized on the damaged box too.