# JD401C reverse problem



## mlappin (Jun 25, 2009)

So I have a JD401C that has an issue with the reverser. Shift into forward its fine, flipping the lever into reverse and its a long time finally locking up tight. Once locked in you can stand on the brakes in about any gear and kill the engine, so once in, no slip.

We have a JD400 that also had issues once, had to go 4-5-6-7-8 when on the road to get it up to speed or the reverser would slip. Tore that one down probably over twenty years ago and all it needed was all new o-rings on the internal tubes that transferred oil to wither clutch pack. Installed all new sealing rings as well while it was apart.

I'm pretty sure with the 401 its an internal problem with the reverser valve assembly. As I pointed out, forwards is fine, reverse once locked up stays locked and will kill the engine.

I know we have a few longtime JD mechanics as members and was wondering if my theory of a bad gasket in the reverser assembly holds water?

This one gets used way too much to have it down for long if it's more an internal issue rather than external.

Clutch pressures have been adjusted as well as clutch pedal free travel.


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## Tx Jim (Jun 30, 2014)

My knowledge of JD industrial tractors is very limited as I was employed at an "agriculture only" dealership. My 1st thought is to check linkage to be sure reverser control valve is being shifted fully into reverse position. Control linkage has a history of getting worn therefore not shifting valve correctly.


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## mlappin (Jun 25, 2009)

Tx Jim said:


> My knowledge of JD industrial tractors is very limited as I was employed at an "agriculture only" dealership. My 1st thought is to check linkage to be sure reverser control valve is being shifted fully into reverse position. Control linkage has a history of getting worn therefore not shifting valve correctly.


I've checked that but I'll check again, I'm pretty sure the only "stops" in the linkage is in the valve itself. The backhoes is so worn out it probably has twice the travel the 401 has.


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## Tx Jim (Jun 30, 2014)

I can't remember if shift valve has a port to check pressure in reverse. I'll advise you to acquire a 401C tech manual.


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## mlappin (Jun 25, 2009)

Tx Jim said:


> I can't remember if shift valve has a port to check pressure in reverse. I'll advise you to acquire a 401C tech manual.


They do, they have two 1/8" pipe plugs in the top of the body, one for forward, one for reverse, both read the same more or less once reverse actually locks up. I have the sections on valve body adjustment, clutch pedal adjustment (two stage clutch) and clutch finger adjustment.

I'm still thinking its a valve body issue, they have the build in accumulator to adjust shift speed, I'm wondering if a gasket is blown somewhere for the reverse circuit and it leaks too much oil off as they do have the adjustment screw that controls shift speed, thinking is its leaking a tad less than the screw port can supply whence the long lag before it locks up tight. I'm thinking once first cutting is finally done, order the required gaskets and try that first. If that doesn't fix it might have to wait till this winter to split it and rebuild the internals in the reverser assembly.


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