UPDATE: Diesel to flush transmission???

[jigglypuff]

Update: so after a lot of consideration and enjoying the conversation on this forum, I decided to do a diesel flush.

I appreciate all the advice and my decision was informed by, and considered, all the advice. In the end my old school uncle, who has done diesel transmission flushes for longer than I’ve been alive, convinced me.

My procedure: 1. Drain tranny overnight, clean filter screen. 2. Replace screen and all plugs, fill tranny with three gallons of diesel. 3. Run engine for three minutes (no play on hitch or loader). 4. Drain diesel overnight, clean screen. 5. Replace plugs, screen, fill to specs with hydraulic oil. 6. Back in business

I admit that I was skeptical at first and remained so after reading reply’s to my original thread, and was leaning toward a straight hydraulic oil flush. In the end I trusted my uncles judgement.

After running the clean diesel for three minutes, it drained out a milky colored thicker consistency that told me it flushed out a high percentage of the water contaminated hydro fluid.

The hydraulics are back in good working order and everything seems to be working right. Any long term affects to the pump or it’s seals will be reported here, but nothing noticeably out of wack after running a tiller on the back end for a couple hours.

This might not have been the “right” way to flush a transmission, but it was a way that worked for me. I guess you don’t always have to follow the textbook when it comes to certain things.

Any comments or questions welcome


Hi

On another thread I’m getting some great advice on addressing some hydraulic issues (no lift, water contamination, possible crossed hoses) on my new to me L3000DT 4wd, manual trans. I planned to address the problem in part, by draining and flushing the transmission (7.4 gal capacity) twice before final fill. Flushing with cheapest possible hydro oil.

I stopped at a local kubota dealer to wish and browse new tractors and a friendly mechanic suggested I simply add three gallons of diesel, yes, diesel, to the drained transmission, run engine for two minutes (don’t work hitch or loader) drain out diesel, then make final fill with clean hydro fluid. The end

I did a double take and asked “diesel in the transmission??” to which the mechanic replied with a smile “it’s amazing what diesel can clean.” I asked at least two more times and he said it’ll do the job, save 15 gallons of wasted hydro oil and that $6 of diesel vs $100 + of hydro fluid (using cheapest stuff) is obviously cheaper.

A forum search on this came up empty and was wondering if others have tried this or had any hot takes on this method?

Would diesel have an adverse effect on the L3000 DT dry clutch or gears? Is this crazy?

I’m intrigued.

 

[whitetiger]

Hi

On another thread I’m getting some great advice on addressing some hydraulic issues (no lift, water contamination, possible crossed hoses) on my new to me L3000DT 4wd, manual trans. I planned to address the problem in part, by draining and flushing the transmission (7.4 gal capacity) twice before final fill. Flushing with cheapest possible hydro oil.

I stopped at a local kubota dealer to wish and browse new tractors and a friendly mechanic suggested I simply add three gallons of diesel, yes, diesel, to the drained transmission, run engine for two minutes (don’t work hitch or loader) drain out diesel, then make final fill with clean hydro fluid. The end

I did a double take and asked “diesel in the transmission??” to which the mechanic replied with a smile “it’s amazing what diesel can clean.” I asked at least two more times and he said it’ll do the job, save 15 gallons of wasted hydro oil and that $6 of diesel vs $100 + of hydro fluid (using cheapest stuff) is obviously cheaper.

A forum search on this came up empty and was wondering if others have tried this or had any hot takes on this method?

Would diesel have an adverse effect on the L3000 DT dry clutch or gears? Is this crazy?

I’m intrigued.

The clutch never has any fluid on it.
The diesel would not have any adverse effect on the gears.
Problem is, diesel is not a very good lubricant for bearings, thrust washers, bushings, etc. Worse yet is your hydraulic pump is circulating fluid any time the engine is running and diesel fuel could destroy it. Also, you would have diesel throughout the hydraulic system which would contaminate the new hydraulic oil as soon as the engine is started. If your tractor is a hydrostat, it would be a catastrophic disastrous result.

Do not add diesel to flush your system, use hydraulic fluid only. When flushing the system, you only need to pour in 3 gallons of fluid, no need to fill it to the MAX mark.

 

[SDT]

Hi

On another thread I’m getting some great advice on addressing some hydraulic issues (no lift, water contamination, possible crossed hoses) on my new to me L3000DT 4wd, manual trans. I planned to address the problem in part, by draining and flushing the transmission (7.4 gal capacity) twice before final fill. Flushing with cheapest possible hydro oil.

I stopped at a local kubota dealer to wish and browse new tractors and a friendly mechanic suggested I simply add three gallons of diesel, yes, diesel, to the drained transmission, run engine for two minutes (don’t work hitch or loader) drain out diesel, then make final fill with clean hydro fluid. The end

I did a double take and asked “diesel in the transmission??” to which the mechanic replied with a smile “it’s amazing what diesel can clean.” I asked at least two more times and he said it’ll do the job, save 15 gallons of wasted hydro oil and that $6 of diesel vs $100 + of hydro fluid (using cheapest stuff) is obviously cheaper.

A forum search on this came up empty and was wondering if others have tried this or had any hot takes on this method?

Would diesel have an adverse effect on the L3000 DT dry clutch or gears? Is this crazy?

I’m intrigued.

I've done it multiple times on older tractors. I have operated the engines much longer than two minutes with mostly diesel in the transmission sumps without ill effects.

Of course, one would never do this in a HST transmission.

Fully lower lift and change filter(s) before refilling with the correct oil. I usually allow sumps to drain overnight with all drain plugs removed.

SDT

 

[jigglypuff]

The clutch never has any fluid on it.
The diesel would not have any adverse effect on the gears.
Problem is, diesel is not a very good lubricant for bearings, thrust washers, bushings, etc. Worse yet is your hydraulic pump is circulating fluid any time the engine is running and diesel fuel could destroy it. Also, you would have diesel throughout the hydraulic system which would contaminate the new hydraulic oil as soon as the engine is started. If your tractor is a hydrostat, it would be a catastrophic disastrous result.

Do not add diesel to flush your system, use hydraulic fluid only. When flushing the system, you only need to pour in 3 gallons of fluid, no need to fill it to the MAX mark.

The tractor is not HST, its gear driven. Have to stop completely to switch gears.
Good to hear that I can use only about 3 gallons, not the full capacity. Thanks for the tip!

 

[jigglypuff]

I've done it multiple times on older tractors. I have operated the engines much longer than two minutes with mostly diesel in the transmission sumps without ill effects.

Of course, one would never do this in a HST transmission.

Fully lower lift and change filter(s) before refilling with the correct oil. I usually allow sumps to drain overnight with all drain plugs removed.

SDT

Would my 2000-2003 count as an older tractor? The l3000dt is a non hst transmission and only has one filter in the form of a small tube like strainer. Are you saying this diesel procedure would have no I’ll affect on my particular tractor?

 

[SDT]

Would my 2000-2003 count as an older tractor? The l3000dt is a non hst transmission and only has one filter in the form of a small tube like strainer. Are you saying this diesel procedure would have no I’ll affect on my particular tractor?

If you are asking if I have ever used diesel fuel to flush the transmission of an L3000dt, the answer is no.

That said, I would not hesitate to use diesel fuel to flush a gear type transmission for a short period.

Not a HST or GST, only gear type.

I would certainly clean the strainer after the procedure and before adding the correct oil.

SDT

 

[North Idaho Wolfman]

I think you missed the part where whitetiger said that running it with diesel in the sump can destroy the hydraulic pump.
One thing that wasn't mentioned is the PS control, the seals in those are very adverse to any contamination, including fuel oil.

Flush it with cheap Hydraulic oil and nothing else!

 

[jigglypuff]

I think you missed the part where whitetiger said that running it with diesel in the sump can destroy the hydraulic pump.
One thing that wasn't mentioned is the PS control, the seals in those are very adverse to any contamination, including fuel oil.

Flush it with cheap Hydraulic oil and nothing else!

I did overlook that part I guess. If one runs an engine for two minutes with diesel in tranny, how much diesel would circulate through the pump if the hitch or loader are not moved? Does the tranny circulate fluids to the pump immediately upon engine start?

Sorry if I'm naive about this, Im a novice at tractor mechanics and am willing to learn and pick up a few tricks too.

 

[RCW]

While I can't speak to the diesel-flush issue, the hydraulic system is open center.

An open center system circulates fluid through the looped circuit(s) at all times, whether implements are moving or not.

Thus, fluid would be going through the pump at all times the engine is running.

 

[jigglypuff]

While I can't speak to the diesel-flush issue, the hydraulic system is open center.

An open center system circulates fluid through the looped circuit(s) at all times, whether implements are moving or not.

Thus, fluid would be going through the pump at all times the engine is running.

Ah, ok. Thanks for that explanation. Sounds like diesel in the pump is a bad thing, even in short bursts

 

[SDT]

I think you missed the part where whitetiger said that running it with diesel in the sump can destroy the hydraulic pump.
One thing that wasn't mentioned is the PS control, the seals in those are very adverse to any contamination, including fuel oil.

Flush it with cheap Hydraulic oil and nothing else!

It will be interesting to learn why/how diesel oil, which is a lubricant, could damage PS or hydraulic pump seals, which are, no doubt, neoprene or similar synthetic materials.

Note: Not biodiesel, which I would not use in anything at any time for any reason.

SDT

 

[GeoHorn]

It will be interesting to learn why/how diesel oil, which is a lubricant, could damage PS or hydraulic pump seals, which are, no doubt, neoprene or similar synthetic materials.

Note: Not biodiesel, which I would not use in anything at any time for any reason.

SDT

Before I”d use diesel fuel... I’d use cheap lightweight motor oil. Before I’d use cheap lightweight motor oil... I’d use cheap hydraulic oil. A cheap hydraulic oil is generic auto transmisison fluid that can be bought for about the same as diesel.

 

[jigglypuff]

Before I”d use diesel fuel... I’d use cheap lightweight motor oil. Before I’d use cheap lightweight motor oil... I’d use cheap hydraulic oil. A cheap hydraulic oil is generic auto transmisison fluid that can be bought for about the same as diesel.

Good point. Seems though, that cheap hydro fluid is cheaper than cheap auto tranny fluid, at least around my parts.

At this point it seems that there’s a consensus that a diesel flush is not recommended, despite the kubota mechanic and my old school uncle’s insistence that it’ll do the job. Their take is that a gear tractor would handle diesel in tranny and clean well, but I got no take from them wether or not diesel will affect the hydraulic pump. I’ll go with caution and flush with cheap hydraulic fluid and NOT diesel.

I’ll follow user whitetigers advice and use 3 gallons for the flush. Should I still do this twice, at three gallons per flush? I’ve seen in other posts that one flush is sufficient, so I’m not quite sure. I still intend to use the sea foam too.

 

[SDT]

Good point. Seems though, that cheap hydro fluid is cheaper than cheap auto tranny fluid, at least around my parts.

At this point it seems that there’s a consensus that a diesel flush is not recommended, despite the kubota mechanic and my old school uncle’s insistence that it’ll do the job. Their take is that a gear tractor would handle diesel in tranny and clean well, but I got no take from them wether or not diesel will affect the hydraulic pump. I’ll go with caution and flush with cheap hydraulic fluid and NOT diesel.

I’ll follow user whitetigers advice and use 3 gallons for the flush. Should I still do this twice, at three gallons per flush? I’ve seen in other posts that one flush is sufficient, so I’m not quite sure. I still intend to use the sea foam too.

If mine (aside from using diesel) I would probably flush twice and certainly operate for more than two minutes.

I would also be much more reticent to use Sea Foam, or just about any other snake oil, than diesel , cheap hydraulic oil, etc.

SDT

 

[D2Cat]

I had water in the manual 4 speed transmission in my trencher. I drained everything and flushed it using the Super UDT I had drained from my L4240 HST. Ran it around for 5-10 minutes and drained. It is a totally separate unit (just a transmission) from any hydraulics on the machine.

 

[jigglypuff]

If mine (aside from using diesel) I would probably flush twice and certainly operate for more than two minutes.
SDT

I had planned to run the engine with cheap hydraulic fluid til it got up to temperature - 20 minutes or so. Then give the loader and hitch some play to run fluid through there.

Can I still run it to temperature filled with only three gallons per flush? Or do I have to fill to capacity (7.4 gallons)?

 

[SDT]

I had planned to run the engine with cheap hydraulic fluid til it got up to temperature - 20 minutes or so. Then give the loader and hitch some play to run fluid through there.

Can I still run it to temperature filled with only three gallons per flush? Or do I have to fill to capacity (7.4 gallons)?

Avoid the Sea Foam.

Use diesel or cheap tractor fluid per your persuasion. Your' call.

Two minutes is insufficient to fulsh anything.

Two, three, five, ten gallons ? Who knows? Whatever is sufficient to maintain oil level above the level of the inlet strainer.

This is not rocket science.

Neither cheap tractor fluid nor diesel fluid will harm your gear driven Kubota, given the absence of abuse.

Gheese!

SDT

 

[jigglypuff]

Avoid the Sea Foam.

Use diesel or cheap tractor fluid per your persuasion. Your' call.

Two minutes is insufficient to fulsh anything.

Two, three, five, ten gallons ? Who knows? Whatever is sufficient to maintain oil level above the level of the inlet strainer.

This is not rocket science.

Neither cheap tractor fluid nor diesel fluid will harm your gear driven Kubota, given the absence of abuse.

Gheese!

SDT

Thanks for the input. I know it’s not rocket science to list, but it’s kinda rocket science to me. How do I know that I’m maintaining the oil level above the inlet strainer? The trans capacity is 7.4 gallons

 

[SDT]

Thanks for the input. I know it’s not rocket science to list, but it’s kinda rocket science to me. How do I know that I’m maintaining the oil level above the inlet strainer? The trans capacity is 7.4 gallons

If you must be ABSOLUTELY sure, fill to the "low" mark on the dipstick.

If you need only be "confident" pour in 3 or 4 gallons and move on.

SDT

 

[WheelHorseNick]

I've heard of people recommending a diesel flush on the old gear-drive transmission in the old Wheel Horses. Granted, they are transmissions only, no hoses, no hydraulics, just strictly a gear box.

I've never done it myself, but again, I've heard it recommended before.