Lotus Elan and Lotus Elan Plus 2 Forums

Just noticed I never responded with the fix for this!

In the end it was caused by the worm gear on the gearbox output shaft being a little loose.
So nothing to do with right angle drives, cables, speedo etc.....

This worm gear is held in place purely with a friction joint that is tightended by a bolt (from memory) on the end of the output shaft.

When my engine was out (about 16,000 miles ago) we did a minor maintenace overhaul on the gearbox too and found this joint loose.

Hey presto.....almost perfect speedo.

Peter

Was just about to reply with the same answer and then realised how old the thread was - I had a similar thing happen with my 5 speed box (reported on another thread ages ago) jumping speedo then nothing at all. Careful use of a variable speed drill showed that the speedo and cable were fine so it was the drive gear on the output shaft of the gearbox...

Over a weekend, my father and I then took the engine and gearbox out, tightened up the nut on the end of the output shaft and then put it all back together. Fixed. (we did sort a few other things out at the same time mind!)

C

I have replaced my speedo drive on my 5 speed gearbox, I did it from inside the cab, mats out insulation off then cut a small triangle of glassfibre away from in front of the gearstick then with a long socket extention you can remove the 1/4" whit hex head screw that holds the fork clamp. Then with a coat hanger suitable bent the speedo drive will lift out. Easy!!

Yes, that bit is relatively easy, however, if the drive gear that's on the gearbox output shaft comes loose (i.e. the gear in the gearbox that drives the speedo drive) you've got no other way of fixing it than taking the engine out...

It's very frustrating as it's a very simple fix (you just re-torque the big nut in the propshaft flange on the output drive shaft from the gearbox) once you've you've got the engine and gearbox out.

C

I have a new one (+2 speedo cable) I bought by mistake for my S4. Its a little longer than the baby elan. Any one needs it they can have it for 75% of what RD charges.

James