J Type Overdrive slipping

[sparky_spit]

After surviving 2800 miles on the 10CR plus 900 miles on last weekend's Nachtrit, the J type overdrive on my single rail box has started slipping. This happened about 10 miles from home on the way back from the Nachtrit, so it was fairly condsiderate of it really.

Oil level is correct; solenoid operating okay; it's okay when cold; new oil and both filters and the ball-valve cleaned 4k ago, but when it's hot it feels the same as clutch slip does.

So what do we think? One-way clutch knackered?

One small point... the solenoid casing is an original one and a bit loose, and so it moves slightly when engaged. Could this cause slipping when hot, or am I clutching at straws? What does the solenoid actually push inside the OD? A mechanical lever or a hydraulic valve/piston? Whatever it is, is it sensitive to the amount of throw it receives?

[StagNL]

The solenoid casing moving about shouldn't be a worry in my opinion if it ain't much.  I take it the solenoid fastening nut is taught?  Anyway, what it operates is indeed a hydraulic valve system.

What you describe is very similar to my J-type slipping when hot.  It was fine cold but after 15 minutes or so it could start slipping.  Mine also slipped when the balance of the car was not neutral, i.e. when applying throttle on exiting a corner but before the cars' balance has returned to the centre.  

What happens if you drive for a while without engaging OD?  I drove a week without trouble only for it to return upon the first engagement of OD.

I my case the clutch linings were a little worn (pieces missing - I have photos), the flywheel clutch was a tad thin and my thrust bearings had found a way into the sump.  Somewhere amidst that lay my problem.  I have yet to put it all back together....  

Julian

[Alex]

I had the same problem on my spit 1500 when I got it.
I asked an overdrive specialist what they thought and they said to replace the cage thing in the overdrive unit.....unidirectional clutch?
It was a relatively easy thing to do just required the replacement cage and a gasket.

[Doug Paterson]

I had the same symptoms on a 6 month old recon unit with about 1000 miles on it.

One of the following 3 things fixed it (or a combination of the 3) as I did all at once in an effort to get it fully operational for La Carrera Cannonball

1.  Refilling with a lighter oil (EP75/80) as opposed to EP90 - don't think it was this and I'm going back to 80/90 this year.
2.  Changing the O-rings on the Solenoid Valve
3.  Fixing the play in the Solenoid body.  Issue was that one of the roll pins had dropped out allowing the body to move - noticeably.  I replaced the roll pin with one from a spare solenoid.

I think it was either 2 or 3 which did the business - my money is on 3.

The movement of the body could reduce the ultimate movement of the valve itself.

Its a cheap fix so I say - try 2 and 3.  Will cost you about £1 in parts......

It has been faultless for 4000 miles since.

[Pete Lewis]

have a browse at  
http://www.buckeyetriumphs.org/technical/jod/JOD1/JOD1.htm

there's 4 parts in the section but it covers just about everything J type   Pete

[Velocita Rosso]

Mike
If you want a professional answer, put the question to Peter at Overdrive services in Killamarsh near Rotherham. he`s the bees knees and wont tout for business unless its necessary. Ive been up there a few times(only 20 mins away) and given a bit of business.
If he then gives an opinion that it needs to go in ,we could come to some arrangement of getting it there