Zf 4wg130

[KinkFM]

Hello all, I am new here and have a problem with my 'new' Hyundai HL730-7. The machine has less than 3000 running hours and is in new condition. However, it seems like the torque converter is not working properly. Especially in 3rd and 4th gear, it does not reach its speed. The maximum speed is 27 km/h where it should actually be 37 km/h.

There are no fault codes, and the gearbox shifts smoothly. The gearboxbox temperature is 50°C to 60°C. Anyone have an idea what could be causing this? Thanks in advance, Hains

 

[Vetech63]

A lot of factors determine max travel speed. Tire diameter, engine high idle, torque lock up.if equipped, retarded if equipped.....all have to be perfectly tuned. The only place that happens is at the factory when new......or in some engineers mind when he does his calculations. He'll, 27 km is fast enough

 

[KinkFM]

A lot of factors determine max travel speed. Tire diameter, engine high idle, torque lock up.if equipped, retarded if equipped.....all have to be perfectly tuned. The only place that happens is at the factory when new......or in some engineers mind when he does his calculations. He'll, 27 km is fast enough

The machine is fitted with standard factory tyres and the engine runs 2150 rpm. My main concern is whether there are any internal problems with the gearbox, or how I can possibly test this. At 30% speed difference from the factory value, it seems to me that something is not properly adjusted.

 

[Vetech63]

The machine is fitted with standard factory tyres and the engine runs 2150 rpm. My main concern is whether there are any internal problems with the gearbox, or how I can possibly test this. At 30% speed difference from the factory value, it seems to me that something is not properly adjusted.

If you are going to compare your machine to every parameter on a sales spec sheet............you're going to be looking for a lot of problems that aren't necessarily there.

 

[Bigbert]

Hi KinkFM,
my questions might sound strange, but I got these phenomenons in my business life in several cases:
1) Please check oil level in tranny. Low performance especially in 3rd, 4th might be caused by too much oil in transmission. Breather (on top of housing) is clear? Else a proper oil level check will not be possible. Possibly take it off completely.
2) Floor mat in cabine does not touch brake pedal? Brake drums got normal temperature after some ride?
3) how is speed in 3rd reverse? Similar to 3rd forward?

 

[Bigbert]

...and another idea:
Is the correct dipstick in the oil tube?
The oil level (transmission warm, neutral, engine at idle speed) should be around 50 to 70 mm BELOW center output shaft. When cold it might be a bit lower.

 

[KinkFM]

...and another idea:
Is the correct dipstick in the oil tube?
The oil level (transmission warm, neutral, engine at idle speed) should be around 50 to 70 mm BELOW center output shaft. When cold it might be a bit lower.

In the meantime, I have a new oil filter on order so I am sure there is no fault there. I read that Case recommends Hy-tran ultra in the 4wg130, and 15w40 engine oil in heavier ones? Hyundai talks about 10w30 / 15w-40 engine oil in the 4wg130. Which one is correct? As for the other tips, I'll let you know.

 

[Bigbert]

Hi KinkFM,

please see attached the lubrificant list of ZF for this kind of transmissions.
At the end it doesn't matter which viscosity 10W-40 means 10W for winter, 40 for warm.
Use any engine oil from the list, oil type has nothing to do with your issues.

 

[KinkFM]

...and another idea:
Is the correct dipstick in the oil tube?
The oil level (transmission warm, neutral, engine at idle speed) should be around 50 to 70 mm BELOW center output shaft. When cold it might be a bit lower.

Hello Bigbert,

This week, I'll get back to working on the machine. So far, I have checked the breather, and it is fine. You say the oil level should be about 50 mm below the central shaft when the transmission is warm. Do you mean below no.6? Centre shaft to oil level, or bottom shaft oil level? Both times there is not much oil left in the gearbox, and is also lower than the dipstick.

 

[Bigbert]

Hi KinkFM,
position 6 is correct. Oil level (engine idle speed, transmission warm, neutral) must be around 50 mm below mid/center/centre output shaft.There are usually three marks on dipstick, warm max, warm min (70-80 degrees C) and cold min. (40 degrees). With current european starting temps (0-10 degrees) 10-20 mm below cold min should be ok.
Please later check questions 2) and 3) from my 1st post.

 

[KinkFM]

I changed the oil today, but it made no difference.

The brake pedal and brakes come off fine. When I lift the machine I can turn the wheels well by hand.

The reverse speed is the same as the forward speed.

 

[Bigbert]

Hi KinkFM again,

so do I understand you right? 3rd reverse is as slow as 3rd F?
What is speed of engine with converter stalled?
Tests: A) Shift 2nd F, step fully on brake, wide open throttle (WOT), read engine speed.
B) Shift 4th F, same engine rpm?

You said you did an oil change: Old oil was clear, no smell of burnt or dragging clutches?

High idle speed of engine is 2150 rpm? Or higher?
Which engine speed when travelling WOT in 2nd, 3rd, 4th?

 

[KinkFM]

Hello,

Indeed, travellingspeed was about 18 km/h. Both directions.

Test A, full throttle 2200 rpm, when in gear it decreases to 2115 rpm.

Test B, same rpm.

Oil seemed to be ok. No strange smell.

Engine runs 2nd gear 2180rpm, 3th gear 2165 and 4th gear 2140.

 

[Bigbert]

Hmmm, really crazy.

Engine, converter, transmission seem to be allright.

Are tires worn out extremely different?

Are you sure when travelling there is no residual pressure built up in brakes?

Getting hot somehow ?

Check ratio of axles. Did someone change out differential inserts?

Possibly take out rear prop shaft for test.

You see I'm running out of ideas.

 

[KinkFM]

Yes it remains strange. To my mind, the stall rpm is on the high side. I saw in a manual of a newer Hyundai, but with the same transmission also described a stall test. I will also do the 'full stall test', see what the rpm becomes then.

The wheels are all worn the same. I will try to build a measuring point on the brake line, then I can see if there is residual pressure while driving.

I still need to check the gear ratio in the axles/end drives.