just discovered- no reverse.....

[kwd509]

64 2a Diesel..... it had been abandoned for nearly 30 years......working on the transfer case, changing output seals and gasket between transfer case and gearbox....... As the gearbox is sitting on workbench and will soon be the focus of work (and learning), I started working the selectors today and ran through all 4 forward gears. But for reverse, the selector seems not to slide all the way, and the transmission remains in neutral.


I assume the first step is to determine if this is a selector problem or an internal gearing problem. Is there an easy way?
Thanks.

[SafeAirOne]

There should be a threaded rod and a jam nut sticking from the back of the transmission, through the vertical face of the transfer case, right behind the transmission shifter cover and just above the larger inspection cover on the top of the transfer case.

This threaded rod limits the travel of the reverse selector. Make sure the back of the reverse shifter rod isn't hitting the limiter before reverse is fully engaged. There is a small plate on top of the shifter cover that is held on with 2 screws. Under there, you have access to the reverse selector rod and the limiter.

If the shifter cover is off, you will be able to see what's going on inside the transmission as the reverse gear is visible using a flashlight. It should just slide rearward on its shaft to engage the gearing on both the mainshaft and the layshaft simultaneously, providing the other gears are in neutral.

[Apis Mellifera]

Try spinning the input shaft as you shift. You can remove the cover from the selector rods and look down in to see the reverse shift fork and idler. The fork could be broken or misaligned or the idler damaged.

[kwd509]

A little brushing, tad of brake Cleaning fluid /exterior cleaning, then spinning shaft and gentle persuasion and it had loosened up quite nicely.

Am I safe to say this calls for cleaning selector rods, rather than delving into gears?

Plan on removing cover tomorrow to have a peek.

Thanks.

[Apis Mellifera]

I'd be willing to bet the detent balls are sticking. The design flaw is that each half of the cylinder they live in is in a piece of cast aluminum. When the cover is joined to the gearbox case, the cylinder can be out of round. This can make the balls either stuck in or stuck out, despite the spring. The result is a difficult shift or a gear that jumps out on overrun. On my SIII, I replaced the selector rod seals, fitted the cover, and then drilled the detent ball holes 1/64 larger.