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7040 Transmission

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=131181
Printed Date: 28 Sep 2024 at 2:23pm
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Topic: 7040 Transmission
Posted By: WNeuberg53
Subject: 7040 Transmission
Date Posted: 10 Nov 2016 at 8:28pm
Going to look at a 7040 with power divider trans tomorrow. Is there anything I need to watch out for? The newest Allis we have is the WD series so this is a huge step up and any help would be appreciated



Replies:
Posted By: Tbone95
Date Posted: 10 Nov 2016 at 9:12pm
Well, first off, "Power Director"

They are pretty bullet proof. Do routine common sense stuff like make sure it will go into all of the gears. There can be linkage type issues which are relatively simple, but you're going to want to know. Make sure the floor buttons work, these are shift on the go. When you step on the foot clutch, it will automatically drop these to low, that's normal. But it should shift into high, and stay there even at low engine RPM Stand on the breaks good when you're driving and you should be able to stall the tractor. If not (and the breaks work!), the torque limiter is slipping. Bigger dollars there.   


Posted By: Orange Blood
Date Posted: 11 Nov 2016 at 3:53pm
I know this is a little late for you possibly, but additionally cold oil will mask minor PD problems in some cases.  It's a good idea to let the tractor warm up to operating temp, drive it around a little bit, and then what I do is put it in low range, 1st gear, and drag the brakes heavily but not locked, and shift the floor buttons both ways, with the engine about 2200 RPM.  If that passes, I do the same thing again, still low range but in the top trans gear.  If the engine revs at all, first let go of the brakes, and quickly bring the throttle back down so you don't damage anything further, but you will know you have either a slipping Power Director, or Torque Limiter.  If you do get slippage, for an instant while the power train is slipping, quickly turn the steering wheel both ways about half a turn each direction, if it is hard likely the torque limiter is slipping, if the steering is still easy, the Power Director is likely slipping.  The Torque limiter is somewhat less work to fix, but I always pull the Power Director when it is split just to look things over, and replace the seals, because I don't like splitting them twice. 

A slipping Power Director does not always mean a split is required, low hydraulic circuit pressure can be the cause of it, and that pump is external as well as the pressure regulating valve, but if pressure has been low for very long, you clutch packs are probably toast, due to heat buildup from slipping.

A note on the amount of braking, don't lug the tractor down with the brakes to the point of actually stalling the tractor, just make the engine work like it is pulling a big disk.  There is an actual procedure that forces the torque limiter to slip, which requires a healthy amount of brakes.  If you brake too hard, you WILL get slip, because you are supposed to.

Something else to check, is the trans brake, To check it, drive the tractor, depress the foot clutch only about 2/3s of the way to the floor, the tractor should coast, and only stop from rolling friction, or foot brake application.  Do the same test, and this time without going faster than walking speed, depress the clutch all the way to the floor, if adjusted properly, and everything is working, the tractor will come to a pretty quick stop, might even bump you forward in the seat, but it shouldn't slam you through the windshield either.

The inching clutch function should also be checked.  This is accomplished by depressing the clutch fully, placing the tractor in a desired gear, say low range, and an upper gear, and only a bump above idle.  Very slowly raise the foot clutch, the first inch or so of foot travel, won't really do anything as the clutch brake is still on, but as you move beyond that first bit of travel the inching clutch feature will start to move the tractor slowly.  At this time the trans brake, and the low side Power Director Clutch marginally engage at the same time, if you continue to slowly raise the foot clutch you will feel a slight change in clutch spring pressure in your foot, at that point the clutch brake is off, and the low side clutch fully engages and the tractor will move at full speed for that gear selection, the portion of travel for the inching feature is very slight, and is easy to miss.  It operates hydraulically the same way a dry engine clutch would that you are used to in your WD45, gradually engaging the clutch, but the travel is very slight from not engaged to engaged, no more than 2" is my experience. 


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Still in use:
HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060
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Posted By: WNeuberg53
Date Posted: 11 Nov 2016 at 9:44pm
Thanks for the input guys. All seemed good so I bought her, can't wait to get it home.



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