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DoubleTrouble

Power Max 4041 Hydro Problems

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DoubleTrouble
Hey to all; I have just bought a Power Max 4041 Model # 990954 and am trying to get it going. I got it fired up and running but the tractor will not move under its own power. I have checked the belt tension and the hydro-fluid. All I get is the tractor will ease forward like it wants to move but that it. If I jack the rear end off the floor the tires will turn but not when you lower it down. It has a Sundstrand Hydro-Transmission Model # 90-1113 in it. I was hoping that someone here could point me in the right direction and maybe even link me up to some repair manuals for both the tractor and the hydro-Transmission. Thanks in advance

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StanD
Does your clutch pedal have at least 1 inch of free play? Are belts OEM or aftermarket? Pivit point on lower section of clutch are usually worn out, bushings & shaft causing only one belt to pull. Also bearings in lower unit could be bad & seizing. Replace them before you end up needing shaft & pulley. Lastly could be hyro filter or hydro but usually one of the first. Yes, buy a service manual. StanD

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DoubleTrouble
Thhanks for the quick replys; The belts are tight and the tension spring is set at 8" as per owners manual. I'm not sure if the belts are OEM or not but I would guess they are OEM cause the tractor only has 730 hours on it. As far as the clutch pedal it as right at an inch play. I need more info as far as what you are calling the lower unit? are you talking about the Sundstrand Hydro-Transmission? or the gear box behind it? Is there a way to check the pivot point for ware or is this an educated guess.

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StanD
Lower unit of clutch being the lower housing, double pulley, & stub shaft. This the unit that pivets to loosen and tighten the drive belts. The bushings and shaft where this piveting assembly is keeps the belts in perfect alignhment, otherwise assemb. will cock slightly & one belt has to do all the work.If the bearings in lower unit are bad it can cause the same problem & also destoy the double pulley & stub shaft. StanD

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D-17_Dave
The reference to the "lower unit" and such is to help confirm your not loosing input power to the hydro pump. Since you have verified the belt adjustments then remove the cover from the top of the torque housing behind the dash and watch the input shaft of the hydro while running when you put the pump on stroke. You could have a missing key in a coupling or still have belts worn and slipping but a visual inspection of the rotating shaft will help identify this. This is about all you can do without a set of test gauges to test the pressures of both the charge pump and the high pressure pump.

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DoubleTrouble
The torque housing cover has been removed and both (upper and lower) shafts are rotating. The tractor tries to move but just tightens everything up like its going to move and that's it. This could be a shear key problem??? I am trying to round up a set of hyd gauges. Can you just hook them up to the quick disconnects on the front of the tractor or not? The 3 point hitch all works like it should. Are they controlled by the same pump???

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JP
Sure, lift one rear w/out the other off the ground, watch the drive shaft while trying to turn. It should turn (drive shaft) when one of tires are off the ground on each side.....

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CarlH
If you have not done so yet, changing the fluid and filter (using the correct Simplicity filter) may help. A plugged or incorrect filter can affect the performance of the hydro unit.

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D-17_Dave
You can watch the lower end of the charge pressure on the lift side of the relief valve only by plumbing into the quick couplings. This won't really tell you anything you NEED to know. You'll need several gauges at varying pressure levels and a repair manual to properly get into the hydro side of things. If the brakes work, even a little, then you can start the tractor and hold one side on hard then the other while the tractor is in forward. If you have a problem with the drop housings this will tell you which side. If the splined output shaft is stripped on the inside of the rear end it won't show you anything. If this didn't help, I'd jack one side up at the time and try to turn each wheel by hand or with a cheater bar for leverage. If one side turns freely after breaking loose the friction from the problem then that side will turn freely. The other side should have more resistance.

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DoubleTrouble
Sorry for so many question but this is all new to me. What kind of pressure I should read on the hyd. gauge? I was able to find one but it only goes upto 600 PSI. I will check the one tire up one on ground to night when I get home. As far as a filter it has a fram PH16 on it now is this the right on or should I switch. I will be changing it anyway just need to know what to replace it with?

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UCD
Fram filter is one of your problems. With these tractors one size fits all cheap filters do not work good. Replace the filter with an OEM Simplicity filter or a quality Wix, Napa, or Baldwin filter. Others have had problems similar to yours using Fram filters. They have replaced the filter and installed new fluid and cured their problems. Not saying it will cure your problems but it is a good place to start.

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Ronald Hribar
If you do change oil and filter, check the archives for correct procedure on draining,filling and priming system. Also believe you are not to push tractor when system is dry. But that may not be true.

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Brian313
I would start with what UCD said about the Fram Filter. Volvo penta marine engines instantly voids any and all warranties by using fram filters. And I believe mercruiser is right behind them.

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UCD
http://www.simpletractors.com/club2/topic.asp?ARCHIVE=true&TOPIC_ID=73310 http://www.simpletractors.com/club2/topic.asp?ARCHIVE=true&TOPIC_ID=36446 http://www.simpletractors.com/club2/topic.asp?ARCHIVE=true&TOPIC_ID=22583

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DoubleTrouble
Going back to what JP said earlier, I jacked up the tractor and tried to turn each wheel by hand. As I turned the Left tire there was some resistance but it turned but not the drive shaft. As I turned the right tire it turned freely with no resistance and the drive shaft did not turn. Is this a sign of a sheared key or something worse??? Can anyone verify what Ronald Hribar said about moving these tractors with a dry system??? Thanks to everyone for all the help!!!

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D-17_Dave
The resistance should be from you turning the differential gear section inside the rear end. With less resistance on the right side I'd say you have a splined section of a shaft ground up. This may be the shaft on the top of the drop housing or the output shaft of the rear end or the splined coupling that connects the 2 said shafts. Either way the input drive shaft should not turn unless you apply a LOT of force to the wheels AND put the pump on stroke. The hydrostatic pumps of this style are made up of 3 basic parts. 1, a positive displacement pump. When the engine turns the piston pumps' "rotating group" and the hydro's forward/reverse lever is in neutral the pump doesn't move any oil. When you place it "on stroke", it pushes oil in whichever direction you selected with the lever and oil travels to the motor. 2, the motor is inside the rear of the hydro case and has a fixed "rotor". This is the same section as the pump has but the rotor is in a fixed angle. The output shaft of the motor connects straight to the gears inside the rear end. This type of hydrostatic transmission is called a closed loop system and loops the oil flow in a circle between the pump and motor. This system works well and is a standard method of converting mechanical energy into fluid motion then back to mechanical energy. However there is some loss of efficiency involved, but it's controllable. 3, the last part is the charge pump. This pump builds low pressure and supplies the "loop" of oil inside the pump/motor with whatever amount of oil leaks out of the loop. The tolerances are very tight but some oil must leak out of the loop so as to cool and lubricate the system. Therefor if some leaks out, you must resupply the loop or the pump has nothing to build pressure against. In these systems the loop has the priority then the rest of the unused oil is tapped of and used for the lift. Now, going back to Ron's statement. If you turn the wheels without disconnecting the motor from the system the motor now becomes the pump. With nowhere for the oil to go it must bleed off internally or something must give. The result is a broken gear section inside the pump or motor which would be catastrophic. On the powermax's you can simply shaft the mechanical part of the tranny into neutral at the shifter. On the smaller tractors with Sundstrand pumps you must raise the pressure valves so the oil has an escape route. This will not allow you to pull the tractor at any speed but it will let you roll it into the shop or on or off a trailer in a freewheel mode. The older Vickers equipped tractors have a lever to disengage the hydro from the gears mechanical and no damage will result to the hydro from any speed of towing. Bottom line is any way you turn the tires you most likely won't see the input shaft turn regardless of the condition of any of the tranny parts due to the tremendous gear reduction between the hydro and the tires. I hope this makes sense. I also hope my computer doesn't lock up as it took me 30 minuets to two finger type all this out.:o)

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DoubleTrouble
Thanks for all the info I will be working on it this afternoon I hope doing a fluid and filter change and checking out all the other lead everyone has posted. Thanks again for all the help!!!

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UCD
There are two models of the Sundstrand 15 series hydrostatic transmission. The U type and the IN-line type. The Pow'r Max tractors use the In-line type. SundStrand series 15 In-line Hydrostatic unit Repair Manual http://www.simplicitytechpubs.com/6767PRINT/PDF_files/TP_500_0234_00_XX_S.pdf SundStrand series 15 U type Hydrostatic unit Repair Manual http://www.simplicitytechpubs.com/6767PRINT/PDF_files/TP_500_0235_00_XX_S.pdf


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arnoldir
Hello, Sorry for not chiming in sooner, but had to resolve my membership dues. I purchased a 720 and it had the same problem, very little torque at the wheels, and almost no pressure a the rear lift. It was fitted with the Fram filter. Replaced with Simplicity filter (no fluid change) and the tractor immediately regained the ability to spin the tires if the loader bucket was dug into the ground, and would eaisly lif a 300 lb box blade. The filter is on the suction side of the pump and can NOT be tighter than about 20 micron mesh, or it starves the pumps. My 2 cents, please value acordingly.

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DoubleTrouble
I have changed the filter to a NAPA/WIX brand and I have bleed/primed the pump by unscrewing the 3 setscrews one at a time and cranking the engine over till fluid came out, Which was almost as soon as I hit the key. I don't know if I was doing this right but I still can not get the tractor to move. I don't think that it could have gotten fluid through the filter that fast. Thank for all the help.

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DoubleTrouble
The input shaft going into the pump is turning thats as far as I have gotten on it next will be to do some checks back at the wheels and drop housings. The driveshaft you are refuring to is that in the pump/gear box or in the drop housing? I wont have a chance to work on it for a week or two as I will be out of town but I will post the results as soon as I can. Thanks

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