jamesmartin
Well-Known Member
depends on amount but if oil was fairly clean without blackening or metal sheen then i would be happy
Dead normal don't worry about it.
It would of course been better had you said this in the first place. You have something sticking in the box. As the oil and box warms it is freeing off. Possibly a piston in the valve block. Or a solenoid valve sticking.
Keith i think if either of the sprag clutches fail no amount of warming up or running of engine is going to make them work. They just fail to grip and that's and end to it.
Datatek
Well-Known Member
You are most likely right Tony, but looking at the cam mechanism that operates the 1st gear sprag I just thought it could be sticking.
If he had not just changed the oil, maybe you would say warm up is thinning oil, then thinner oil is getting through parially blocked filter. Common enough problem for sticky gear changes when cold. But as he has changed oil and filter it sounds to me like it's a sticky valve not engaging drive clutch. Then when the oil and gearbox internals get warm it frees off. Possibly a valve block clean would sort it. But that is not really a job you want to try unless you have done a few before or have a full set of service sheets to work with. Even then it's a bloody mine field with all the different rate springs to contend with. Used to do the old model 35s almost blindfold, but these things look a bit more of a proposition. You can buy a service tray for them i believe with compartments for each component so you strip and rebuild in a logical sequence. But my days of stripping these things are long gone.
jamesmartin
Well-Known Member
cleaning them in jizer tank can make one lock up that wasnt (sticking),and so presumably fresh oil will as oil has high detergent qualities,how log that lasts in p38s is something i have no experience as often whole unit is loose and beyond sticking up in classics and disco 200 and 300 would often work again fine
Yeah your right James. They can be bloody finicky things to play with. Specially if you've never seen inside one before. You only need a knats whisker in some to screw them up, others seem to work fine full of ****.
Datatek
Well-Known Member
Just changed the oil for the third time and this time I dropped the sump and fitted a new filter. Not a lot of **** in the bottom but a thin coat of a sort of grey slime. It's made a little difference to the dodgy changes, 1st to 2nd is now normal but 2nd to 3rd is still accompanied by a burst of revs. So it looks like the box will have to come out. Can't make up my mind whether to use the one out of my spares dog with 162K on it or to go for a re-con from Ashcrofts. Will have to decide soon.
Looks a bloody great lump to get out, any tips welcome, like is it better to take the transfer box off first and then the box or hit it all in one lump?
The burst of revs is caused by one clutch letting go and the next one not acting quickly enough. Changing from 2nd to 3rd, clutch 6 disengages and clutch 5 engages. That is supposed to happen simultaniously but there is obviously a pause occuring. Still say you have a sticky valve block.
Datatek
Well-Known Member
From a base of no knowledge, that is what it has always seemed to me. Don't fancy dropping the valve block in situe though. I've tried swapping the ECU and just about everything else I can think of. Others seem to think it's a clutch pack, but it engages with such a jolt it does not feel like a slipping clutch to me. I'm using it as a manual at the moment and it changes fine if I back off the throttle and it will pull with no slip (apart from the torque converter until it locks) in third, with the torque convertor locked the drive is solid in third.
jamesmartin
Well-Known Member
if you have spare box for parts they are reasonably easy for competent person to do ,although dont strip valve block theres nothing you can do to it that washing in paraffin or such wont do + thers a few tiny plastic ball that fit in specfic places easily lost if worn you cant repair as machined fit parts ,since no black in oil it is probably oneway clutch or sprag clutch same thing easy checked as should only turn one way and grab instantly the other
