Testing the overdrive.

[bennygoodman]

I'm in the final stages of my GT6 restoration and was just wondering before I put everything back together is there any way of testing if the overdrive is working without actually driving the car?

[yorkshire_spam]

When I refitted mine I ran the engine without the propshaft connected to test the OD

[Andy Flexney]

put some tape round the input shaft, and fasten it in to a drill that has plenty of torque. Get the gearbox spinning and flick in the overdrive. You will notice the propshaft flange will turn quicker and you the drill makes a different sound. Have someone holding the gearbox or fasten it to the bench otherwise it might spin over when you start the drill.

AndyF

[Royboy66]

That's what I did  8)

http://youtu.be/tliIRyrtLuQ

[Phwoar]

royboy66 wrote:

That's what I did  8)

http://youtu.be/tliIRyrtLuQ

Well now, there's a trick, I don't think it would have occurred to me do that and I've got a couple of gearboxes that need testing.

Proper job.

[Pete Lewis]

if you want to test a gearbox or overdrive you should really drive the mainshaft and check the change in revs and synchro
action by checking the spin up of the input shaft ( with a clutch disc fitted)
might seem  odd but all gear box operation  be it synchro or over drive  is actually driven from the mainshaft , not the input shaft.

does take more power to turn but  will test  sychro/baulking/clashing /OD pump/ operation properly .

you should be able to change gears without crashing whilst under power the sync rings will spin the disc up /or down and allow smooth selection to take place . (  this is how it works when driving)

Pete

[Freebird]

You can check that the OD comes in and out this way, but not whether it's up to transmitting the power to the road without fitting it to the car.

I recently fitted a 2nd hand J type to our Spitty and found the uni directional clutch slips if provoked giving all the symtpoms of clutch slip when the OD is disengaged. So now it's got to come out again - Grrrrrrrr.

[UJPrice]

Freebird wrote:

You can check that the OD comes in and out this way, but not whether it's up to transmitting the power to the road without fitting it to the car.

I recently fitted a 2nd hand J type to our Spitty and found the uni directional clutch slips if provoked giving all the symtpoms of clutch slip when the OD is disengaged. So now it's got to come out again - Grrrrrrrr.

Bloody thing, should have checked it before we put it in or at least before we put all the interior back in. Wish this thread was created sooner  ;)