No forward movement but reverse works L3750dt

[heppeone]

Hi all. Still working on my L3750dt traveling issue, forward travel limited to the lowest gears (8-gear trans/ 4 high- 4 low), reverse works fine in all 8. Tractor has the Hydraulic Shuttle type, with a single disk dry clutch and FEL. I used the FEL quite a bit before this problem started happening, honestly I was learning how to use it at the time and probably (likely***129315 made mistakes in clutch use.

I split the tractor today to replace clutch, unfortunately I ordered the parts for a dual clutch, but, I’m not seeing what I’d consider a damaged clutch disk and plates don’t “look” bad either. Thoughts?

Sometimes I can get forward gears to engage by switching from reverse into forward several times, without using the clutch, then will start slipping out again. The shuttle control valve allows this model to shift without using the clutch. Thoughts?

Appreciate any input, I’ve got the workshop manuals for tractor, but not some of the special testing tools etc.

 

[Roadworthy]

Is it possible something with the shifters is misaligned or bent? It could even be an interlock thing.

 

[rbargeron]

IMHO the issue is all in the hydraulic shuttle valve. The forward clutch pack isn't getting pressurized and/or is leaking down, failing to remain engaged. Check the shuttle linkage first - it may not be pushing the valve far enough. The shuttle is a pair of wet clutch packs inside the transmission - they are likely ok if reverse works. The shuttle valve may have a problem. Study the WSM and parts drawings, take the valve apart and clean it out. Good luck, Dick B

 

[SidecarFlip]

IMHO the issue is all in the hydraulic shuttle valve. The forward clutch pack isn't getting pressurized and/or is leaking down, failing to remain engaged. Check the shuttle linkage first - it may not be pushing the valve far enough. The shuttle is a pair of wet clutch packs inside the transmission - they are likely ok if reverse works. The shuttle valve may have a problem. Study the WSM and parts drawings, take the valve apart and clean it out. Good luck, Dick B

Exactly and the valve is externally accessable. You need the WSM to ascertain the correct lockup pressure as well as a liquid filled gauge and adapter to access the gauge port to obtain the reading. Just upped the lockup pressure on my used M9 a month ago. The WSM will call out the correct pressure range.

It is possible that the pack has issues but if it did, you'd have no movement at all. I strongly suspect the valve body has some crud in it or the pressure relief valve is not operating correctly.

Have to ask you if you are changing the fluid at recommended intervals or just forgetting about it?

 

[North Idaho Wolfman]

Hi all. Still working on my L3750dt traveling issue, forward travel limited to the lowest gears (8-gear trans/ 4 high- 4 low), reverse works fine in all 8. Tractor has the Hydraulic Shuttle type, with a single disk dry clutch and FEL. I used the FEL quite a bit before this problem started happening, honestly I was learning how to use it at the time and probably (likely***129315 made mistakes in clutch use.

I split the tractor today to replace clutch, unfortunately I ordered the parts for a dual clutch, but, I’m not seeing what I’d consider a damaged clutch disk and plates don’t “look” bad either. Thoughts?

Sometimes I can get forward gears to engage by switching from reverse into forward several times, without using the clutch, then will start slipping out again. The shuttle control valve allows this model to shift without using the clutch. Thoughts?

Appreciate any input, I’ve got the workshop manuals for tractor, but not some of the special testing tools etc.

You've went into the mechanical clutch, but have you went into the hydraulic clutch pack?
Because it goes into reverse easy and all the time, I'll say I suspect that you have a synco issue on the forward side of things.

 

[North Idaho Wolfman]

It is possible that the pack has issues but if it did, you'd have no movement at all. I strongly suspect the valve body has some crud in it or the pressure relief valve is not operating correctly.

That's not true, it has a dual clutch pack so it's very possible that the forward section of the clutch pack is damaged yet the Reverse section is still intact.

 

[SidecarFlip]

Think I'd still start at the easiest part, the external modulating valve and check the lockup pressure and see if there is any crud in it before getting inside the case.

 

[heppeone]

Thanks everyone, I’m not receiving notifications when replies come in, maybe I need to update my email address. Regardless, thanks for the advise and recommendations. The tractor is still split due to hurricane chores, I do have the shuttle valve off, will disassemble and examine. Wish I had pressure checked system prior to splitting, but some had me convinced it was the clutch, though I’ve doubted that from the beginning. Will update

 

[heppeone]

Update Sept 22 2019 (new ((same)) issue

IÂ’ll keep it short. Got tractor put back together with new fluid, put original clutch back in because it looked completely fine and was within spec. Test went great, all gears working as should, forward/reverse, high/low, 4wd and pto, FEL also did great at dirt pile. Put back on work pad to button up a few other items then noticed a leak on shuttle valve pipe fitting requiring me to address, I jacked wheels up so I could diagnose which pipe fitting it was while catching lost fluid. Fixxed issue and ran tractor through all the gears while still jacked up, no issues.

HereÂ’s where the problem comes in. I put tractor down to start work, lost both forward and reverse gears ***129318;***8205;***9794;***65039;, back on pad via granny gear.

K, hereÂ’s what I learned just prior to putting together. When I went to replace hydro filter, I found a large piece of debris in filter housing on intake side, dealer said itÂ’s a piece of brake pad ***128549;, so obviously thereÂ’s debris in the system. I have disconnected the brake linkage system to possibly avoid more debris entering the fluid. What I KNOW is, both clutch systems work, as well as priority valve, shuttle valve, hydraulic pump, I say this because everything worked. Probably should not have run tractor through all her gears while on jacks, too high rpms in the rearend most likely kicking up debris that may have settled.

So, my thought is I must flush entire system at very least, and rear taken apart to fix brake disks, though honestly taking that apart may have to wait, flat property and not in my best health. HereÂ’s my question, is there a good way to flush out the entire hydro system? I plan to capture the oil and filter through cheese cloth or the like and reuse to keep flushing.

Anyone had to go through this? Advise? Always open to good ideas. The advise yÂ’all have given above has been great, and thanks.

 

[North Idaho Wolfman]

Update Sept 22 2019 (new ((same)) issue

IÂ***8217;ll keep it short. Got tractor put back together with new fluid, put original clutch back in because it looked completely fine and was within spec. Test went great, all gears working as should, forward/reverse, high/low, 4wd and pto, FEL also did great at dirt pile. Put back on work pad to button up a few other items then noticed a leak on shuttle valve pipe fitting requiring me to address, I jacked wheels up so I could diagnose which pipe fitting it was while catching lost fluid. Fixxed issue and ran tractor through all the gears while still jacked up, no issues.

HereÂ***8217;s where the problem comes in. I put tractor down to start work, lost both forward and reverse gears ***129318;***8205;***9794;***65039;, back on pad via granny gear.

K, hereÂ***8217;s what I learned just prior to putting together. When I went to replace hydro filter, I found a large piece of debris in filter housing on intake side, dealer said itÂ***8217;s a piece of brake pad ***128549;, so obviously thereÂ***8217;s debris in the system. I have disconnected the brake linkage system to possibly avoid more debris entering the fluid. What I KNOW is, both clutch systems work, as well as priority valve, shuttle valve, hydraulic pump, I say this because everything worked. Probably should not have run tractor through all her gears while on jacks, too high rpms in the rearend most likely kicking up debris that may have settled.

So, my thought is I must flush entire system at very least, and rear taken apart to fix brake disks, though honestly taking that apart may have to wait, flat property and not in my best health. HereÂ***8217;s my question, is there a good way to flush out the entire hydro system? I plan to capture the oil and filter through cheese cloth or the like and reuse to keep flushing.

Anyone had to go through this? Advise? Always open to good ideas. The advise yÂ***8217;all have given above has been great, and thanks.

I really shouldn't matter what debri is in the fluid, as it gets filtered before it's delivered to any system.

There really isn't much of a way to flush it out unless you just dump a bunch of fluid in it and then drain it back out.
Losing more than you had lost originally makes me wonder.
Did you take the entice clutch apart and check the drum seals?

 

[heppeone]

Not sure which seal you are referring to. I hsve not gone into the hydraulic clutch, yet.

 

[heppeone]

For anyone following, including myself for future reference, hereÂ’s latest updat on Sept 25 2019

Drained hydraulic fluid again, new filter, put filtered fluid back in, same issues. Decided to remove FEL to get to all hydraulic system easier. Soon as I disconnected the hoses I got power steering back at low rpm, took tractor for a spin and although thereÂ’s still a slight delay with forward high gears engaging, it ran all around the property.

Thinking a good complete hydraulic system test is in order, starting with the pump. Any thoughts regarding the FEL system? Could there be an issue in there? Really do use FEL far more often than 3-point/pto system.