HST Plus DS Hi/Lo hiccup

[rScotty]

The other day an odd thing happened as I was driving the M59 back to where it sleeps.

I had been doing some backhoe crane work, & was just putting along at maybe 1800 RPM in high range with the dual speed (DS) lever in Hi. At a small incline I didn't change the foot pedal, pushed the dual speed lever down for Lo .... - and the tractor suddenly felt like I had stepped on the brakes and the engine stalled.

After checking it over I re-started and everything seems fine now - although I am not sure it is responding the same as it used to when the DS lever is in Lo.... I'm not quite sure. It sort of feels like it does in 4wd - but it's not. Like a slight bit of extra drag or if the brakes were slightly on. If anything changed, it's very slight & subtle. I usually work with the DS in Hi & set there it is just the same as always.

The next day it wouldn't start and that turned out to be a corroded battery terminal.... and that might have been the cause of the stall.

But now I'm a little suspicious of shifting to Lo & I'm wondering if anything similar has happened to anyone else with a HST+ transmission?

rScotty

 

[Smokeydog]

Not yet. Strange hiccup but you are probably right about the battery connection being suspect. Routinely shift to low in high range to climb the driveway. Back to high, high coming down.
Switching regularly hi/lo in medium range for mowing and FEL work.
Happy traxx

 

[rScotty]

Yes, it hasn't done it again. I replaced the original battery terminal connectors after it happened - had to, since they were all eaten up - I'm unimpressed with both the original battery cables and connectors. Some time before I had ordered nice battery post connectors from Amazon but hadn't put them on.

Today I was doing some maintenance and noticed that although it normally runs in Manual HST mode and slow attack, the HST optional setting had somehow changed to Auto H-DS and fast attack. So I changed it back to Manual and Slow attack & things seem normal again.

Last week the hiccup might have been three things all happening at the same time: an electrical glitch that happened just at the same moment I manually toggled the DS for LO, and also at that same moment the Auto H-DS "intelligent" shifter decided that it was time to auto-downshift to LO. So I got LO gear, but the electrical glitch shut down the motor. Hopefully it doesn't happen again.

Also took the opportunity today to remove the hand brake and switch the EGR valve back on.
rScotty

 

[wmonroe]

What do you mean “switch the egr valve back on”?

I would bet the glitch was like you stated a stack up of things that all happened at once. The corroded battery cables probably didn’t help either.

 

[rScotty]

What do you mean “switch the egr valve back on”?

I would bet the glitch was like you stated a stack up of things that all happened at once. The corroded battery cables probably didn’t help either.

The EGR valve is activated by a temperature-sensitive pressure switch. By putting a valve in the pressure line the EGR can be controlled to produce less heavy black smoke.

 

[5030]

I love black smoke...lol Tells me it's working.

 

[Fallon]

I love black smoke...lol Tells me it's working.

Black smoke is just unburnt fuel going out the exhaust. At the fuel prices these days I don't find it that entertaining.

 

[rScotty]

I love black smoke...lol Tells me it's working.

Not me. To me black smoke says the engine is struggling with a poor mixture. Probably it's struggling because I'm not in sync with the throttle and the load. Black smoke makes me think, "Oops, I can do better than that."
rScotty

 

[5030]

Your view and mine differ.

 

[rScotty]

Your view and mine differ.

Well that's fine. Hopefully it won't be the last time. It's already not the first or only...

 

[wmonroe]

The EGR valve is activated by a temperature-sensitive pressure switch. By putting a valve in the pressure line the EGR can be controlled to produce less heavy black smoke.

Got it, thanks

 

[mikester]

When was the last time you did a full hydraulic fluid change? I find my HST more responsive with less HI/LOW hunting/hesitation in 3rd gear. I haven't noticed the hesitation in 1st or 2nd.

 

[rScotty]

Got it, thanks

A bit more info.... Kubota'a version of an EGR valve is nothing at all like the simple old EGR "clatter valves" used on automotive gas engine intake manifolds for a couple of decades in the late 60s to 80s.

The Kubota version is pretty complex & was only used for a few years. I don't know if Kubota's EGR engines had anything to do with emissions regulations, but adding an EGR to their popular & proven old direct injection 03-M series engines just happened to fit a loophole called the "Interim" Tier 4 Emission Regulations.

That loophole allowed Kubota to continue with their old proven 03-M direct mechanical injection engine in some tractors from 2007 to 2012 . The EGR version was discontinued when the interim regs expired and soot (black smoke) reduction became more strict.

Those EGR motors appear to be good reliable engines. Maybe they are a bit of a fuel hog like any diesel that "rolls coal" when loaded down.... As near as I can tell by turning the EGR on our M59 on and off, it's not the EGR that makes them smoke. I'm not 100% sure, but suspect they smoke because of retarded injector timing to produce less NOx emissions - which also fits the Interim Tier 4 regs.
rScotty

 

[rScotty]

When was the last time you did a full hydraulic fluid change? I find my HST more responsive with less HI/LOW hunting/hesitation in 3rd gear. I haven't noticed the hesitation in 1st or 2nd.

Well, that's interesting. How did you know? I am probably due for a full hydraulic fluid and filter change. It has about 400 to 500 hours on the last one. I don't use the fluid hard and rarely use over half throttle unless I'm roading it. The fluid is perfectly clear and tests well on blotter paper. I'm considering just swapping in a few quarts of new SUDT to offset any additive depletion and perhaps changing the filter.

Up until that single isolated instance I had never noticed any Hi/Lo hunting in 1st, 2nd, or 3rd range. But then I don't use HST+ Autoshift, just the manual trigger on the steering column. It's always been instantaneous until the hiccup.
rScotty

 

[5030]

Well that's fine. Hopefully it won't be the last time. It's already not the first or only...

One never knows do they? I probably should have said, not continuous black smoke, only time mine blow off visible particulates (smoke) is when throttling up or assuming a load (like spooling up my disc bine). When running, they just give off heat from the stacks, no visible smoke at all.

Continuous black smoke is an indicator of over fueling or a clogged air filter or some other issue that needs addressed.

If course the post 4 units 'digest' that smoke in the SCR units or the DEF units in the case of larger displacement units which at some point need cleaned or renewed. The smoke is still there, you just don't see it...

 

[5030]

The Kubota version is pretty complex & was only used for a few years. I don't know if Kubota's EGR engines had anything to do with emissions regulations, but adding an EGR to their popular & proven old direct injection 03-M series engines just happened to fit a loophole called the "Interim" Tier 4 Emission Regulations.

Interesting comment. According to my shop manuals, both of my M9's are 'Interem Tier 4' engines but neither have any sort of EGR on them. The only device they have on them is the wastegate or what I refer to as the 'puff limiter' which is similar to what Mack used on their diesel engines to mitigate the 'puff of black smoke when throttling up the engines. The ones I have are a spring loaded affair that I've never fooled with. No need to. Well depicted in the workshop manuals. Both of mine are the 3 valve engines as well.

 

[wmonroe]

I agree the retarded valve timing causes some smoke and also greatly contributes to the smokey cold starts. The same engine prior to interim tier 4 had the timing advanced quite a bit more. It’s on my to do list to adjust but haven’t found the time yet.