Hd6 wet clutch pump

Hello all, does anyone know of a replacement pump for the wet clutch on my hd6? Mine is toast so I rigged up a diesel lift pump to a switch but I don't think it's building enough pressure to over come the filter and internals plus it loses prime very easy. Im open to suggestions or replacements. Thanks

Unfortunately I don't have the pump any more.

I have the small pump t 27491 = 620201

I should have the pump fork and I try to open the pump for check inside condition

I check the inside pump and she loog good but the fine shimm inside is bad and when am turning the shaft left side she oké but right side he turne and stop and have the fork

Am tinking the pump need the gasket 621363 inside for adjustement but am not a mechanic men

They are a 'barnes' pump. And afaik are same fuel pump is used on smaller detroit 2 strokes

tits tyres and tracks

they all cost you money

Is there anything different between the pumps on the 344 for pumping oil to the clutch and what the Detroit, im guessing 2-71, would be for pumping fuel? I know it couldn't be as easy as that..lol

I wonder if anyone's tried this or if it can be done. I've had no luck looking up the part number. Salvage yard near me would pull one of an old machine for $300 but I dont know about that. Seems a little high. My buddy has one on a non running 6g but it would be a bear to get to.

Les Kerf wrote:

Primos75 wrote:

I wonder if anyone's tried this or if it can be done. I've had no luck looking up the part number. Salvage yard near me would pull one of an old machine for $300 but I dont know about that. Seems a little high. My buddy has one on a non running 6g but it would be a bear to get to.

This is a screenshot of the Barnes fuel pump for the 2-71 Detroit Diesel from the HD5 parts manual:

That is a left hand pump shown in the photo.

Edited by Codger - 23 Apr 2026 at 5:35am

That's All Folks!

In your application of that pump I've not found any specifications; but they are simple to modify. That spring shown in Les's photo, (#11) is what actually sets the relief pressure, or opens the bypass as mentioned. I've seen those pumps relieve at 20psi, (shot) and I've seen them make in excess of 100psi using diesel fuel as the fluid medium. I've never seen them in a hydraulic fluid other than fueling application myself.

The red pump is from a 6V-92TA, the green pump from an 8V-71, and the yellow pump in back is from a 3-53. All are Detroit engines I currently own. The two front pumps are left hand, the yellow rear pump is right hand. You can ascertain this by looking at the venting ports facing up and are seen on the two front pumps. The relief valves are on the left with the front pumps, on the right with the yellow rear pump in the photo. The wrench on the right is one I bent up to access hidden fasteners and worked well.

I've seen you chasing the same thing over on FB and I've found technical questions are best handled over there unless gossiping about farm stuff which fits well on this site any longer. But that is just my opinion.

Both sites have their place however.

That's All Folks!

It would be helpful to know what PSI the system operated at, as well as flow.

I have never seen the pump AC used. I have replaced a pump in the wet clutch on a Cat 9u D6, it is smaller than the DD fuel pump. But no idea of flow or PSI it operated at.

I know of a late AC HD 11 ag cat the owner had a pump special built to replace the AC pump. This was 20 years ago and was 2000 to 3000 dollars. So adapting a similar pump looks to be a cheaper way to go.

Primos75 wrote:

Very similar to the wet clutch pump i posted. Does anyone know what the psi and gph the pump should have for the clutch? The manual says the filter has a bypass at something like 18psi I think.

I did find some specs on the hydraulic pump for the HD6 steering clutches; it has two sections, one section for each side. It did not give a specification for the pressure but did state that "Hydraulicsystem pressure is non-adjustable; system is designed with proper "built-in" operating pressure to disengage steering clutches"."

The manual does state that each set of gears has 1.5 gallons per minute capacity @1200 rpm.

I would guess that if you found a pump capable of ~2+ GPM and started out at ~20 PSI you could turn up the pressure until it could cycle the clutch it should work.

HD6 Merv wrote:

...

Master clutch oil pump is only a circulating lube pump. And oil pressure is only around 20 psi. I know this because ive seen some late 40M series HD6 that had a clutch pressure gauge fitted in the dash.

Also the drive coupling used on all the pumps is the same 2 fingered 5/16 square coupling used on the GM, as that is what some of us have bought when the pump couplings wear out. The triple section pumps can wear out the couplings if people run too heavier oil in the HD6E tractors

Ahhh... now we are getting somewhere! Big smile

Thanks for the input Thumbs Up

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