Clark 55b transmission slipping?

[Ryan151]

I just bought a Clark 55b I was wondering if anyone had any experience with the transmissions/ torque converters this loader seems to be pretty weak once out of first gear. It moves in the other gears but it does not get up to speed as it should in second and third gear. The engine rpm is governed at 2200 rpm right now which I will be turning up to the 2800 rpm the 4-53 Detroit should be at.

Any help would be great! Thanks!

 

[Mike Van]

I don't know about Clarks, but any of these need the right oil, clean oil, filters & screens to work right -

 

[Ryan151]

Thanks for the reply. I ordered a shop/service manual on the loader so I know what's going on with all that and what exactly to check. Second gear in the loader seems to be the strongest yet it even is still weak.

 

[oldseabee]

engine stall speed is critical to make the convertor give full power to the trans. Stall speed range 1800-1950 RPM at full throttle and hydraulics engaged at 2250 PSI and oil at 180 Deg F. with trans in high gear and machine locked down, Go down through the rest of the gears, observe the drive shaft between the convertor and transmission with the machine locked down and in gear there should be no movement , if the shaft is turning in any gear, the clutch in that gear is slipping, if it is moving in fwd or reverse in all gears then that clutch is slipping.
H Free Idle 2650 RPM.

 

[Ryan151]

What is the converter pressure supposed to be. With cold oil we had 175 psi which I think is too low isn't it supposed to be 240 psi with 180-200 degree oil? Thanks for the info though I hadn't thought about locking it down that way and observing the drive line but if the pressures are not right then the clutches would slip right?

 

[oldseabee]

That pressure you are reading at the convertor is clutch pressure, the clutch pressure regulating valve is mounted on the convertor, it looks like a plumbing fitting. there are two versions that are the same outside but have different pressures depending on what machine it is on, the 55B should be 240 - 280 the other version is 180-220. If some one bought a used one it could be the wrong pressure setting. There is no adjustment just different springs internally. If you have the wrong one you can get a spring set or replace the whole thing.
minnpar.com is handling clark parts also you can get maunals there just down load what you need.

 

[oldseabee]

I went to Lakewood High School grad. 1956.

 

[Ryan151]

Okay I'll check it out and see what I have for a regulator. It does look to have been replaced.... Recently

 

[MJS Services]

Okay I'll check it out and see what I have for a regulator. It does look to have been replaced.... Recently

What trans is in your loader? I have a 45C with the 18000 series, My 4-53 was only turning 2400 rpm's, machine felt like it slipped all the time, got the rpm's up to almost 2700 what a difference! but it still cant compare to my Dresser 515b

 

[Ryan151]

What trans is in your loader? I have a 45C with the 18000 series, My 4-53 was only turning 2400 rpm's, machine felt like it slipped all the time, got the rpm's up to almost 2700 what a difference! but it still cant compare to my Dresser 515b

I have a 28000 series trans Ill check the rpms and get them set to the proper spec of 2650 as the previous poster said. I know a 4-53 is good for up to 2800 but the converter ect may not be good for that high.

 

[Ryan151]

Still Having issues with this transmission. It does operate better now that I changed the oil and installed a filter(it was missing lol) trans was about 2 gallons low as well. Now however I am having oil leak out of the breather on the torque converter????? Is the converter possibly leaking and spraying oil up at the breather or maybe the drain is partially plugged? Not a major leak but its enough to make a puddle while is sits and idles for 5-10 minutes.

 

[Ryan151]

Non of the clutches are slipping though! locked the machine down and I get no driveline movement in any gears when engaged. only spins when the wheels turn.

 

[neil283]

Full serial number of machine would help in obtaining the correct pressures and engine speed specs.

 

[Ryan151]

Full serial number of machine would help in obtaining the correct pressures and engine speed specs.

here is the serial number 416C-968-CAC

 

[neil283]

Clutch pressure 240-280 psi
Convertor "In" @2000 RPM 40-75 psi
Convertor "Out" @2000RPM 30-55 psi
Cooler "In" @2000 RPM 20-44 psi
Cooler "Out" @2000RPM 20-25 psi
Convertor leakage 2 GPM Max@2000 RPM No load.
Engine Stall 1800-1950 RPM 3rd gear and hydraulics over relief. Do not stall for more than 30 seconds.
Engine HFI 2650 RPM
Main hydraulic relief pressure 2250 psi

All tests should be carried out at normal operating temperature. (180 deg F ).

Regards

 

[Ryan151]

Thank you Neil! Very good information! I am going to assume with oil coming out of my breather my converter is probably leaking excessively or the drain line is "plugged" or restricted.

 

[oldseabee]

The "breather" on the convertor is actually a check valve to let air in so you can't get a vaccuum in the system but should block oil coming out. there is a plastic check valve inside, and they are prone to come apart over time and start letting oil come out.

 

[Ryan151]

Oh very good thank you

 

[Ryan151]

checked the pressure today on for clutch pressures all gears forward and reverse are reading 162-165psi.... thats a bit far off of what it should be 240-280psi... going to order the proper springs and try that to see if this corrects it. at least I know that the transmission is likely good as all the clutch pressures are dead on together however it is low.

 

[mourafetis]

Hello!!
You can measure the converter leakage by taking the drain to a bucket for 1 min and measuring the amount of oil. If it is more than 2 galons in 1 minute at 2000rpm then you have an issue. If the return line to the transmission is not clogged, then you probably have a worn breather. If you replace it it will all be ok.
Also, if you have a slipping converter, you will get high stall speed (more than 1950 rpm), so it is also a way of determining the status of your converter.
Regards