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D7E transmission FUBAR! Could really use big help! Very sad!

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2 years 10 months ago #234426 by bobby1
Thanks! Luckily I did catch that little tid bit in the manual!!! I certainly wanted to run the engine uncoupled. I figured one of the two sides would have to have axial float to get the yoke installed and take up any variance.

At this point, I am now rolling heavy dice as something else could fail in the machine beyond the transmission.

Before I remove the trans, I would like to find the easiest way to inspect the bevel gear area. This machine got brand new bevel shaft bearings and seals only 60 days before this failure but I fear coolant might have hurt it. Any ideas? Once I make a plan and get better weather, I want to drain all the trans oil so I can inspect everything......hopefully.

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2 years 10 months ago #234430 by edb
Hi bobby1,
looked thru all pages of this thread and these tired old eyes did not seem to find a pic of your machine.

You can easily gain access to the B/Gear area by removing the big round plate on the rear face of the main Steer Clutch and Brake housing/frame
IF you do not have an attachment such as a Winch or Cable Control on there. The standard Cat ripper usually does allow access to said cover plate.

Hyster Power Controlled winches have an issue of seizing up the Fwd or Rev clutches that may lock the transmission live PTO shaft which is the Transmission input shaft flange you tried to turn after removing the uni-joints from the T/C.
These winches are hydraulic controlled and so people have issues in learning how to control these winches and end up frying the said clutches that spin the clutch pack outer cases and plates whilst the drive out discs spin freely inside the clutch drums at a fair amount of speed differential.
The control levers need to be correctly positioned so the brake is released for controlling the winch--if I recall correctly I stand to be corrected.

When the cables get old and full of crud it can be difficult to feel the detented lever positions so the Fwd/Rev clutches can be part applied and overheat and warp the discs/plates.

www.alliedsystems.com/ASP3/winchparts-no...1&filter=&location=&

www.alliedsystems.com/ASP3/winchservice-...1&filter=&location=&

www.alliedsystems.com/ASP3/winchops-noncurrent.asp

If fitted you may find the Military spec winch data here at the Allied web site links above.

Did many of these at the Dealer but I do not know what symptoms the clients had experienced before bringing in said units for us to overhaul.

Cheers,
Eddie B.

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2 years 10 months ago #234435 by edb
Hi bobby1,
I would also like to add that if there is no free play in the Trans shaft then the issue would be within the Trans itself ---if some free play is evident then it may be a Winch or other rear attachment if fitted.
Cheers,
Eddie B.

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2 years 10 months ago #234446 by bobby1
EDB, this machine is certainly fitted with a Hyster D7H winch unit. However, as you describe, I did not detect any free play of the front trans input shaft at all. Once I broke the yoke apart, I tried to move it back and forth with a pry bar. No way it is moving. But if that winch couples to that PTO output shaft at the back of the trans, and the input shaft is continuous to it, it might be something we need to look closer at before a tear down??

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2 years 10 months ago #234447 by Wombat
The input shaft goes right through and is the PTO at the output end of the shaft.

Wombat

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2 years 10 months ago #234448 by bobby1
Appreciate it. Right now I need to determine a way to verify if the winch is causing these issues. I am still absorbing all the material EDB has provided and trying to understand the winch. To be honest, it was not even on my radar to understand it, but seems I better! d

I do believe from the reading, this will be a "power control" winch as it has a hydro pump coupled on the TC housing, and a two lever arrangement on the side of the seat area. There are two cables going to it. Neither of which feel right. I don't think the brake cable will even work at all, and other is not much better.

If someone could quickly explain if there is a scenario in which the winch unit could stop the trans shaft from spinning, even when not running, that would be helpful. It sort of looks like the clutch packs are typically fully engaged and need hydro pressure to open them? or do I understand that right?

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2 years 10 months ago #234460 by Old Magnet
On power shift tractors the winch input shaft is driven from the torque converter output shaft.
The winch input shaft has a hydraulically activated oil-type clutch. There is no connection between the input shaft of the clutch and the output gear (clutch drive) until oil pressure activates the clutch.

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2 years 10 months ago #234461 by bobby1
Thanks! To clarify my understanding per the manuals EDB provided. The "input shaft" going into the winch would be locked to the main axle going through the trans at to the output of the TC and would spin. Power is applied to the winching system through 1 of the 2 clutches, FWD and REV? So there again, if tractor is not running, shaft should be free?

I did take the top plate off the hydro valve for the winch. The levers were a little sticky. The brake lever was nearly completely seized but now moving.

I think my hope is that if I can get the brake released (I think this one is wet and hydraulic?), I'd like to see if I can get the drum to free spool a bit, which should prove the clutches are free?

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2 years 10 months ago - 2 years 10 months ago #234466 by Old Magnet
Again, there is no power or connection going to the winch until the input clutch is engaged.
Directional clutches and brake have no affect on the drive without clutch coupling.
With both directional clutches engaged (no hydraulic pressure) the winch drum cannot turn.
Last edit: 2 years 10 months ago by Old Magnet.

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2 years 10 months ago - 2 years 10 months ago #234480 by edb
Hi Team,
if the winch clutches are seized from overheated buckled discs and plates as described above there will still be some free play in the Trans Input/PTO shaft due to slack in the winch drive coupling splines and the back lash of the winch Bevel Gear and Pinion.
As OM describes above normally the winch Fwd and Rev clutches are free to spin within themselves until a Fwd or Rev clutch is selected--if both clutches are fubar then the unit can be locked as a result or at least getting very hot quickly due to the buckled clutch plates/discs.

As you describe that the Trans input shaft is locked solid I would suspect a planetary gear failure in the transmission.

Scans below are to give you an idea of the Trans layout and how little room there is for stray parts.
You can also see the PTO splined end of the Trans. input shaft.
These scans are typical of a D7-8-9 trans of the day and are from Cat School hand outs from a PS Trans school I did in 1965 as an Apprentice. The pages are from a Service Manual for one of the above machines.

Maybe check the trans suction screen and filter element for metal particles that may have been picked up since testing of the machine.

Hope this helps.
Regards,
Eddie B.
Attachments:
Last edit: 2 years 10 months ago by edb.

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