ZF 4WG 200 Issue

[Jake Tigchelaar]

Hey all, I've got a 2014 Liu Gong CLG 842 III loader with just under 2000 hours. Got it off auction this summer, it'll just be used for snow. It's actually a nice machine - ZF drive train and Cummins engine.

Hasn't done any work yet, just been driving it around for fun. First couple months had no issues, as it got colder (not sure if it's cold related) it started giving me a low trans pressure light as it shifted gears. The light goes away as soon as it shifts. It shifts pretty decent, and haven't noticed anything else concerning. It does this in auto and manual. If I'm in neutral and manually shift through gears, it still gives me the low pressure light.
Did a fluid and filter change and no difference.

Anybody got any ideas as to what might be going on?

 

[old timer]

Hi Jake, lets see if i can help you.

First thing I would do is a main pressure test, not overly familiar with a Lui Gong but with the older ZF's
the main pressure test point is just below the centerline of the transmission control valve. Should be 10 bar minimum (1 bar is 14.7 psi for us math nerds)

If the main pressure seems good but drops a lot when shifting, the next step is to perform a clutch calibration. If it is not available thru the dash menus, you will have to plug it in with an AEB calibration tool (checks the clutch fill time). I might suspect that is your problem, should be done every 500 hours or every transmission oil change.

Seeing as you are in Ontario, might try contacting Bull Powertrain. They have never steered me wrong, might even be able to rent/borrow an AEB.

I have rebuilt my share of those, leave it to the professionals to rebuild. Lots of special tools needed.

Hope this helps, good luck

 

[Jake Tigchelaar]

Thanks for the advice! I figured a pressure test was likely the first step. Appreciate the recommendation. It looks like Bull Powetrain is in Sudbury which is a good 5 hours north of me. I'll do a search for someone more local.

 

[Bigbert]

Hi Jake,

the 4WG200 in your Liugong got a rather simple shift pressure system. The light got some damping delay during long (cold) shifts, but not good enough to overcome cold temps. So either fill in thinner oil, or block radiator by some surface or live with the light coming up.
Famous AEB (clutch calibration) will NOT work on the WG200, only possible with newer trannies like WG130/160/190/210/260/310. The old range WG120/150/180/200/250 has a simple pressure ramp for clutch modulation, no fastfilling etc.

 

[Jake Tigchelaar]

Thanks Bigbert. That's good to know.
Do you guys happen to know the fitting size for the pressure test points?

 

[Bigbert]

M10x1

 

[Nige]

The light got some damping delay during long (cold) shifts, but not good enough to overcome cold temps. So either fill in thinner oil, or block radiator by some surface or live with the light coming up.

Depending on exactly what type of oil is specified for that particular transmission is there a possibility of using a multigrade transmission oil.?

 

[Bigbert]

I'd recommend 5W-40 in this case. See attached the complete list of lubricants.

 

[Jake Tigchelaar]

Thanks all. I had used 15w40 this fluid change. If I find pressures are OK, I may switch to 5w40 as suggested.
I'm also planning to send an oil sample to get tested to be safe.

 

[Jake Tigchelaar]

Hey all, wondering if this new information helps provide a better idea as to the issue.

I haven't had the chance to pressure test yet, but we got our first snow call-out yesterday! It was awesome. Just about 10-12 cm but enough to have some fun. The loader pushed snow awesome. This being the first time we were actually working this machine, I got to see more of what is going on with the transmission. Low pressure light still comes on with every shift, but it seems like 2nd gear is potentially the problem. As soon as I started to push snow in 2nd gear, it would right away kick down to 1st gear. 1st, 3rd and 4th all worked great while pushing.

Just driving in 2nd gear with no load is fine, it's only when there is load on the machine.

Does this information help at all @Bigbert?

 

[Bigbert]

Hi Jake,

so congratulation.
I do not see any issue on tranny right now. The auto shift into 1st is possibly a kind of a kickdown feature: With gaspedal sufficiently down and low ground speed system will select first.
Guess, you operated in pos. 4 on selector. I'd expect no downshift in pos. 2.

Good luck

 

[Jake Tigchelaar]

I was running in 3 on the selector, if I remember correctly I did at one point have it in position 2 and it did kick down, but I can't say with certainty, so I will have to remember to try that next storm.
Thanks!

 

[Jake Tigchelaar]

Update.
I didn't check the screen/filter on the suction tube when I changed the oil originally. I wanted to get lighter weight oil in it, so I did that today. Suction screen was clean. Put in 5w40 oil. Still acting the same. I haven't checked pressures yet, that's next step. There is two kickdown buttons, I checked today and neither of them work.

I can drive in 2nd gear until I have a load on (ie put the snow blade down) and then it automatically kicks down to 1st gear. Every other gear is totally fine.

The fluid level is checked by a site glass on this. I noticed that it doesn't seem accurate based on the amount of fluid I took out. If I go by the site Glass levels, the pump makes a hec of a lot of noise.

Not sure if anything here helps with any diagnosing?? @Bigbert

 

[Bigbert]

Jake, which kind of gear switch is fitted in your Liugong? Photo?
As long as you got min. 15 bar in all clutches when pressurized, everything is fine. Pressure drop during shifts is normal and necessary for modulated slippage of clutches. The colder the oil the longer the modulation, the longer time with "warning" light. However "warning" light during shifts is fully normal. 1 to 2 sec, I'd expect.
I'm not 100% sure how progamming of kickdown is done on Liugong grader. Possibly these guys wanted to avoid too long drive in extreme converter mode in 2nd, so system switches to 1st with heavy load on converter. But again, please share picture of gear switch.