jd400 yellow tractor with backhoe- shuttle shift misery

[markmc60]

I have an old JD400 yellow version, has a front end loader and backhoe attachment.
for years it has been slow to go into forward, well, it sat longer than usual, like 8 months, had no forward, none, nada. so, I pulled the screen and replaced the filters new hyd oil, still no forward, I raised the rear off the ground with the stabs and blocked it up. reverse works, forward just creeps. (I forgot to mention before I blocked it up, had an old fart tell me tow it to "release" any stuck clutches, I did. no work).
was told it was a reverser leaking, I pulled the reverse block and rebuilt it, nothing to it, pulled the in pipes and put new orings on them feeding the reverser. new hyd oil, now, I have nothing in forward or reverse, no pressure at all at the side test points.
HELP

 

[Tx Jim]

Could be leaking fwd clutch pack seals. Does linkage shift reverser control valve correctly IE no loose motion in linkage? Was filters & screen dirty?

 

[markmc60]

Could be leaking fwd clutch pack seals. Does linkage shift reverser control valve correctly IE no loose motion in linkage? Was filters & screen dirty?

nothing loose and shifter moves fine. filters and screen are clean.

and just where in Texas is coyote flats? LOL

 

[jb1390]

nothing loose and shifter moves fine. filters and screen are clean.

and just where in Texas is coyote flats? LOL

I used to own a JD 300 industrial, that I lost forward motion (twice, actually). Here is what I remember off the top of my head:

There is an internal transmission gear pump that provides low pressure (200 psi) oil for a variety of functions. There are priority valves contained in the shifter control block, which is located under the right-hand footrest. The clutch pedal works a valve in this control block, which provides low oil pressure to the reverser valve (contained in the same valve body). The shuttle shifter valve directs that oil to the forward or reverse clutch pack pistons.

Did you split the tractor when you performed work earlier?

Do your other hydraulic functions work correctly?

Before you lost both forward and reverse, did you have pressure at the reverse port, but no/low pressure at the forward port?

 

[markmc60]

I used to own a JD 300 industrial, that I lost forward motion (twice, actually). Here is what I remember off the top of my head:

There is an internal transmission gear pump that provides low pressure (200 psi) oil for a variety of functions. There are priority valves contained in the shifter control block, which is located under the right-hand footrest. The clutch pedal works a valve in this control block, which provides low oil pressure to the reverser valve (contained in the same valve body). The shuttle shifter valve directs that oil to the forward or reverse clutch pack pistons.

Did you split the tractor when you performed work earlier?

Do your other hydraulic functions work correctly?

Before you lost both forward and reverse, did you have pressure at the reverse port, but no/low pressure at the forward port?

did not split the tractor, the "external Hyds work as always. I can't answer your last question, I do not know the answer.

 

[jb1390]

did not split the tractor, the "external Hyds work as always. I can't answer your last question, I do not know the answer.

There are test ports located on the valve body underneath the right footrest. They are straight thread, o-ring seal plugs. ( I think 3/8" fine thread). You will need an adapter fitting, but you need to check pressure at these ports. I believe there are 3 - one overall pressure, and one each for forward and reverse.

When you push the clutch pedal, it rotates a bar which opens a valve. There is a roll pin in the bar that runs underneath the tractor - make sure the roll pin is intact and that the linkage moves correctly.

What did you take apart when trying to fix? Did you take any pictures?

 

[Tx Jim]

and just where in Texas is coyote flats? LOL

30 miles South of Ft Worth according to Google and me

 

[Billrog]

If it doesn't have enough power to spin the wheels when up against something the torch converter may be shot. If so and you replace it , it's a good time to replace the pump as well while your in there it's a 4.5 hr. job.

 

[jb1390]

If it doesn't have enough power to spin the wheels when up against something the torch converter may be shot. If so and you replace it , it's a good time to replace the pump as well while your in there it's a 4.5 hr. job.

I'm pretty sure that his tractor does not have a torque converter. It's a dry clutch, and then 2 sets of wet clutches - one forward and one reverse.

If it's the forward clutch pack or o-ring that needs to be replaced, that's way more than a 4.5 hour job.

 

[Tx Jim]

I'm pretty sure that his tractor does not have a torque converter. It's a dry clutch, and then 2 sets of wet clutches - one forward and one reverse.

Ditto on NO torque converter. It sounds as if reverser clutch linings are toast.