Sliding out of 4th while OD engaged.

[tuko]

On my hybrid I have rebuilt series transmission with a Fairy Overdrive. Both components work great in my hybrid but the past few months she has begun to slide out of 4th when the overdrive is engaged.

Testing to see if it was the transmission is the culprit, I've driven the hybird at various speeds in 4th direct trying to make it slide/jump out of gear, but it won't. But once I have the overdrive engaged and going down the highway a few miles she will slide out of gear again. I've tried this at various speeds and there was no difference.

With reading on this forum I seen many complain of noisy overdrives but I have to say that mine is quiet, theres no additional noises over that of the transmission. Shifting is perfectly smooth, not binding or grinding. This would lead me to think that the overdrive is not at the point of being worn out, but possibly the coupling clutch sleeve is worn.

I found here: http://www.rockymountainspares.co.uk/?page_id=41 that you can buy an "OVERHAUL KIT FOR FAIREY OVERDRIVE COUPLING".

Has anybody 1) had the same problem with their fairy overdrive? 2) installed the above overhaul kit and 3) cured their similar problems?


Cheers,
Todd.

[I Leak Oil]

Have you checked to make sure the main shaft nut is tight?

[tuko]

Have you checked to make sure the main shaft nut is tight?

Jupp, tight as she can be.


Todd.

[I Leak Oil]

Well then that's certainly odd...I can't think of any reason why the OD would have anything to do with the transmission slipping out of gear. When you tested it with the OD disengaged did you run it at the same RPM and grade as you did with it engaged?
The clutch sleeve is working engaged or not but if the nut is tight the internals of the OD shouldn't affect the transmission.
Strange for sure...

[Terrys]

Have you checked to make sure the main shaft nut is tight?

This was my first thought too.

[tuko]

I agree with you both, I saw on this forum that there is a lot of discussions about overdrives so that's why I asked here.

All the other gears stay engaged, it's just 4th thats giving me this headache. BTW, the test runs were on the same road at the same speeds as I usually know where to expect the trans to slide out of gear.

I can check the main shaft nut again as it's been a year since I've had the OD removed.


Todd.

[rejeep]

just in case you haven’t checked.. or looked closely..

I had this problem in my series when I first installed my Roverdrive..
well kind of..

the bend on the overdrive cane was slapping into the gearbox cane enough to slip out of gear.. the shifter didn’t move enough to visually notice at first.. took several minutes to figure it out.. put a slight bend in the cane and no problems..

[I Leak Oil]

I can see that popping the OD out of gear but I don't see it popping his tranny out of 4th gear.

[rejeep]

4th is down and to the right
the OD lever moves forward on my Roverdrive
while engaged in 4th my OD lever did come in contact when shifted until I bent it..
I believe the gearbox is in 4th in this picture.

[I Leak Oil]

OK gotcha! So the OD lever was physically pushing the main gear lever forward, right? (for some reason I can't view your picture)

[LaneRover]

Mine did the first time I drove it so I changed the OD lever. I could see how if it was touching a little that one could knock the other out of gear.

Brent

[tuko]

Interesting response guys and to be honest I would have never thought of that one one. I'll take a look at the OD gear lever but if my memory servers me correctly I seem to think that my lever looks like the image provided, with plenty of clearance from the transmission gear lever.


Todd.

[rejeep]

well that picture was before i put a bend in it.
even if it doesnt clash upon engagement it could vibrate enough to nudge it a bit