Thread: Difficulty with Fairey Overdrive

Most likely gear whine.
The gear on the overdrive has done miles on another transfercase and has worn a certain way.
When you put the overdrive in you have two different gears that have not worn in together and therefore you get noise.
there is little you can do about it.(except for fitting new transfercase and overdrive gears)
If all checks out .....then just drive it and live with the extra noise.

As 101 Ron says. But check whether the operating mechanism is touching the bodywork (I had to shorten the screw on the side of the transmission tunnel which was touching the bracket for the lever). If anything is touching the body it will make it a lot noisier.

If there is slight wear on the output shaft of the overdrive where it rotates on the input shaft, or the input shaft is slightly worn, even if the needle roller bearing was replaced, it will still allow the output gear to move slightly out of line, resulting in the noise you hear.

John

Thanks 101 Ron & John

I compared the gear on the overdrive with the one I removed from the gearbox output.

The one from the gearbox looks much newer and is in very good condition. I guess it's probably been changed at somepoint in Arthur's life.

The one on the overdrive isn't bad, but is comparatively worn. The edges of the teeth are a bit rounded.

I can imagine replace the overdrive's gear would be very expensive, and maybe not possible to even get hold of on.

I wonder if I should ask the engineering firm that changed the bearings to see if they can do something that would make the o/d gear mesh the same way as the gear I pulled off (using it as a template), without having to go to the expense end effort of also replacing the transfer case gear?

--Elvin

Originally Posted by LandyDude

Thanks 101 Ron & John

I compared the gear on the overdrive with the one I removed from the gearbox output.

The one from the gearbox looks much newer and is in very good condition. I guess it's probably been changed at somepoint in Arthur's life.

The one on the overdrive isn't bad, but is comparatively worn. The edges of the teeth are a bit rounded.

I can imagine replace the overdrive's gear would be very expensive, and maybe not possible to even get hold of on.

I wonder if I should ask the engineering firm that changed the bearings to see if they can do something that would make the o/d gear mesh the same way as the gear I pulled off (using it as a template), without having to go to the expense end effort of also replacing the transfer case gear?

--Elvin

The gear is available from Rovers Down South in New Orleans, but is, as you guessed, very expensive. One suggestion I can make is that you check the condition of the idler shaft and needle rollers bearings in your transfer case - any wear here will allow the idler gears to move slightly out of mesh, and become noisy. They can be replaced in situ.

John

The whine may reduce as the gear beds in.

Faireys usually whine quite a bit when engaged, however are usually quiet when disengaged.

What is the gear like on your 2nd fairey? It isn't too difficult to swap them over.

Originally Posted by JDNSW

The gear is available from Rovers Down South in New Orleans, but is, as you guessed, very expensive. One suggestion I can make is that you check the condition of the idler shaft and needle rollers bearings in your transfer case - any wear here will allow the idler gears to move slightly out of mesh, and become noisy. They can be replaced in situ.

John

Thanks John. You're right, I had a look at the price on the Rovers Down South web site and the gear costs more than what I paid for the o/d

I will look into your suggestion on the idler and bearings. In reading the workshop manual its not a quick job, but as you say can be done in situ.

My inital concern is if the noises are going to lead to some damage. I'm planning a longer trip next month and figure if there is any risk in it packing it in when outback I'm better off with out the o/d even if the trip is a bit slower Who needs to drive faster than 75 kph anyway...

~Elvin

Originally Posted by isuzurover

The whine may reduce as the gear beds in.

Faireys usually whine quite a bit when engaged, however are usually quiet when disengaged.

What is the gear like on your 2nd fairey? It isn't too difficult to swap them over.

Thanks Ben

I cleaned up what I thought was the better of the two units. But I think I should fit the other one and see how it compares. If it makes less noise, maybe I should swap the o/d output gear (if the thinking its the bit not meshing right with the transfer case input gear) or I go and reco all the bearings in that unit too and use it instead. The reason I chose the other o/d to fix up was because its synchro ring looked like it was in better condition. Seems I didn't pay enough attention to the output gear.

I'm hoping I can make something good without having to get into pulling bits out of the gearbox or tranfer case as that appears to be a lot more work and no so easy to do on the workbench

~Elvin

Hi Dude,

I think your noise is (as already mentioned) the meshing of the o/d input with the T'case. Not much to add on that...

However - I learned from harsh experience to carry all the parts needed to remove the o/d with me at all times (the stuff you removed to install the o/d). I smeared it all in grease and wrapped it up in an old shirt - that is carried in my tool box. When the input gear or sleeve does go (and eventually one will) you are buggered without the original bits (include a new lock tab as well).

On the T'case idler - it is a very easy job that takes about an hour. I did mine out in the street last year. I replaced the entire gear and bearings as the old gear was very pitted - resulted in a huge reduction in gear whine (unrelated to the o/d).

Cheers,

Adam