HD11E Direct drive trans pressure
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=94941
Printed Date: 03 Jul 2025 at 6:57pm
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Topic: HD11E Direct drive trans pressure
Posted By: Gargoyle
Subject: HD11E Direct drive trans pressure
Date Posted: 10 Sep 2014 at 10:18am
I'm still going round and round with my trans pressure on my 11E serial 8878.
Pressure is very hit or miss. Dave or Trevor or one of the guys here mentioned that I might be sucking air through the cracks in the lines or at the fittings. I done what I can to tighten the fittings and found no cracks and it's not much better.
At times the gauge will read no pressure @ any rpm. If I back the dozer up an incline, so that the right rear is high, and run in neutral, the pressure jumps up. The sump is on the front left of the trans. This suggests to me that the fluid level is low.
I don't have a dipstick and I filled the fluid per the recommended amount. But, is it possible that I'm simply low on fluid?
If you had intermittent pressure, would you be ok with it?
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Replies:
Posted By: gemdozer
Date Posted: 10 Sep 2014 at 12:30pm
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You should have a oil streaner on left side transmission and he is bolt to the stering cluch housing he maybe clogged and you should have to a oil filter on right side did you check it and could be too the oil pump in front transmission is worn and not builting pression
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Posted By: DMiller
Date Posted: 11 Sep 2014 at 7:28am
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If it is similar to our 7G models there is a scavenge strainer at the bottom of the main trans, it takes suction on the lowest point and delivers that oil to the suction housing area at the left mid region strained for use, keeps the main suction for trans pump full so if that strainer is clogged will not deliver in quantity enough to keep from sucking air.
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Posted By: Gargoyle
Date Posted: 11 Sep 2014 at 6:29pm
I finally decided to bite the bullet and pulled the sump. I was curious about the pressure relief valve.. It seemed as though the pump had lost it's prime.. even if they aren't primed.
The pressure release plunger was jammed at the bottom of the valve. I was able to free it, but if it was stuck at the bottom, I don't understand if that would cause the valve to release pressure. I'll have to stare at it some more to figure out how it works.
I'll get it put back in tomorrow.
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Posted By: Gargoyle
Date Posted: 12 Sep 2014 at 6:09pm
Pump is back in.. still can't get it to pump fluid.
The return for the sump is from the bevel gear chamber. How fluid gets to the bevel gear is beyond me.. It must flow from the trans to the bevel gear chamber directly. Anyway, I fought this all day. I opened the filter housing and fired the engine for a moment. I finally started pulling the pressure lines one at a time looking for a clogged line.
I did notice that the pressure line that comes from the bottom of the filter was bone dry. Gravity alone should feed some fluid. I blew the line backwards and got some fluid, but it was very slow. It was cool today and the fluid is pretty thick.. I'm wondering if I made a mistake in using 50 weight drivetrain fluid, instead of hydraulic as Laztyts suggested.
Anyway, it seems that the whole sump system needs to be primed. But I can't see a way to do that.
I'm almost at the point of draining the tranny completely, re-filling with farm hydraulic (starting at the bevel gear chamber) and seeing if I can get some results..
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Posted By: Gargoyle
Date Posted: 12 Sep 2014 at 7:12pm
A few points that I forgot to mention:
The strainer/screen is in the bevel gear case.. It was surprisingly clean.. The filter is new. The filter housing was full of gunk that I cleaned out a year ago.
The sump impellers spin freely, and I'm assuming show wear, but I didn't see anything broken.. I have no way of judging the wear on the impellers, so they might be really worn..
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Posted By: Mactractor
Date Posted: 13 Sep 2014 at 4:31am
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If your tractor is hydraulic steer clutch, 50 weight oil is way too heavy. Some lube guide charts say 30 weight, but that is also too heavy for the steer clutch pump drive. They shear off the drive dogs if you use anything heavier than 20W. 10W auto trans fluid is commonly used in HD6E wet clutch trans/back end and its lubes everything including bevel gear and pinion just fine as it does in the powershift HD6 and HD7G
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Posted By: Gargoyle
Date Posted: 13 Sep 2014 at 10:19am
It's a dry steering clutch..
I went with the factory recommendation, even though Trever here suggested farm hydraulic..
I'm draining the trans today. Going to try hydraulic
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Posted By: gemdozer
Date Posted: 13 Sep 2014 at 11:57am
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The hydrolic oil in transmission should't be good and if you disconnect the suction line from the oil pump and refill that line this could help. and when you refill the transmission the bevel gear case is the same level than the transmission
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Posted By: Gargoyle
Date Posted: 14 Sep 2014 at 5:17pm
With 6.74 gallons of farm hydraulic, I still had no pressure.. I pulled the line at the output side of the sump and had tons of fluid when I throttled up. .. so I started cracking the lines one at a time.. each time I fired it up and throttled up.. the 50 weight that I spent all that money on had clogged the hard lines.. the new hydraulic poured through...
Still no pressure at gauge.. I pulled the line to the pressure gauge and it was clogged and the treads on the gauge shot.. Once I got pressure to the gauge, the connection leaked like crazy and the gauge still read nothing..
I bought a new cheapy oil pressure gauge. As soon as I get a brass connection that will fit the old line and adapt to the new 1/8" plastic tubing that feeds the gauge. I will be set..
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Posted By: Gargoyle
Date Posted: 15 Sep 2014 at 7:25pm
Well if I pull one of the trans lines loose and fire it up, I have no flow at idle, but some flow at higher rpms..
Still no pressure at gauge and very little flow getting to gauge...
I'm thinking its worth a different sump pump. If anyone has a pump in decent shape, let me know, I'd be interested.
Part number 623316
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Posted By: Gargoyle
Date Posted: 24 Sep 2014 at 9:34am
I pulled the pump again. Looked it over, blew it out, put it back together..
On top of the pump was a small plug buried in the grease.. The hex key was stripped out but I managed to get it out. Put in a new one.
Re-installed the pump.. I pulled the new plug and fired up the motor. About 10 seconds and trans fluid spit up through the plug.. I re-installed the plug and in about 15 seconds I had trans pressure.
I'm guessing that air was trapped in the pump. Funny, the manual doesn't even show this plug and my manual didn't mention it..
Lesson learned....
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