Ferret Gearbox Setup

[sexton]

Due to kick-back, I have been checking the X dimensions in a couple of Ferret gearboxes and found them well off. I have been using the table shown in the first photo to set them up. This was taken from the Ferret_Gearbox-Adjustments.pdf found on-line, which is a scan of the 1968 EMER by the looks of it.

 

But then I found the checking tool sketch in the second drawing and the X dimensions are quite different. Anyone know why?

 

Malcolm

 

Malcolm

[Richard Farrant]

Hi Malcolm,

As with all military publications they were constantly updated, in all aspects. The upper picture from EMER dated 1968 is the last revision and the one to use. When I worked for the military it was instilled in us to use the EMER's all the time in case information had been changed. These figures are a guide and especially relevant with new bands, but if you get the X heights to the nearest 0.050" it should be OK.

With respect to Andrew for his drawing, but I suspect the dimensions are from a very early version of the EMER, at least the tool is shown clear.

[robin craig]

Malcolm, when you say "kick back" you are talking about the Gear Change Pedal coming back up much further than normal on a gear change, when it just about puts your knee in your mouth? Is that it?

 

Robin

[sexton]

Richard, Thanks, good to know I am using the right one.

 

Robin, yes, that's what I'm talking about.

 

Malcolm

[Newcoregon]

Thanx all; This is exactly what happened to my Ferret [previous owner]. His foot slipped off a depressed band release lever... it violently sprung back and then went back to the front.. completely worthless..as in limp. I bought the ferret this way and have not been able to repair it.. it seems to be in the gear box? Thanks Newc in Oregon

[Richard Farrant]

Thanx all; This is exactly what happened to my Ferret [previous owner]. His foot slipped off a depressed band release lever... it violently sprung back and then went back to the front.. completely worthless..as in limp. I bought the ferret this way and have not been able to repair it.. it seems to be in the gear box? Thanks Newc in Oregon

 

Hi mate,

This often happens if the band has not been adjusting automatically. It is what is called going "over centre", this is when kick back can occur if you are not firm with the pedal.

 

Richard

[sexton]

So the pedal is just flopping up and down now? That's not good.

 

When you move the pedal up and down, does the short lever mounted on a shaft on the left hand side (looking forward) of the gearbox near the top move backwards and forwards? If it does, this confirms the linkage is still intact. My guess is you have already done this and that's why you now suspect the problem is internal.

 

There are some quite simple checks you can do, but they require access to the top of the gearbox.

 

Take the small cover held on by 4 bolts off. It's the one on the top just to the rear of the gearbox dip stick. In the hole, you will see the lever that is mounted at the other end of the cross shaft the external lever is mounted on.The external lever is item 5, the cross shaft is 3 and the internal lever is 6 on the drg below.

 

Move the external lever backwards and forwards and confirm the internal lever moves up and down. If it doesn't, the cross shaft is sheared or the splines holding the levers on the ends of the shaft have torn out.

 

The end of the internal lever pushes a hollow rod up and down. The hollow rod slides on a solid rod, item 10, that goes down a bar that runs from the front of the gearbox to the back, called the busbar, item 12. The ball at the bottom end of the solid rod is "trapped" in the busbar. You can see this all with a flashlight looking down the hole. Is the hollow rod still attached to the internal lever at the top? Does it slide up and down the solid rod? Is the solid rod still attached to the bus bar below? I suspect this rod may have broken or one of the ends has pulled out of the lever or the busbar.

 

You will also see a large spring under the lever. The rod between it and the busbar, item 15, transfers a very heavy load go the busbar. Are the spring and the rod intact?

 

Malcolm

 

Edited September 28, 2015 by sexton

[sexton]

Thanx all; This is exactly what happened to my Ferret [previous owner]. His foot slipped off a depressed band release lever... it violently sprung back and then went back to the front.. completely worthless..as in limp. I bought the ferret this way and have not been able to repair it.. it seems to be in the gear box? Thanks Newc in Oregon

 

Newc, regarding my reply above, there is something I want to confirm. What I read from your post is that the driver's foot slipped off the pedal, the pedal kicked up hard, and then it just flopped down on its own until it hit the hull. And now you can lift it up and down too easily.

 

But is it possible the driver's foot slipped, the pedal kicked up, and then he pressed the pedal down with neutral engaged? Because if he did depress the pedal fully down after the kick-back, the gearbox could have gone into neutral and got stuck in that gear. This also allows the pedal to be lifted up and down easily, but is is a different problem.

 

So the question is: did the pedal start flopping up and down right after the violent kick-back, or did it start after he pressed it back down with neutral selected?

 

Malcolm

[Newcoregon]

Hi Malcolm; I bought the Ferret from an estate, I used to be the driver for the elderly gent, and his attempt to drive it caused the problem. So far all indications are an internal problem. I need to open the cover and have a good look. Prior to my purchase some fellows attemped to figure it out, but no success. At leased the Clansman ect. is removed and I can get to the top of the gearbox. Thanks much Newc