D6H LGP shifting issue

[Jr Kloulubak]

it will not engage in forward or reverse, sometimes it engages suddenly after a few minutes, trans oil pressure is correct, seems torque converter has lockup issue, any assistance appreciated...

 

[Nige]

Post a Serial Number please. It helps with locating information.

Does the transmission shift linkage feel “sloppy”.?
What oil are you using in the transmission. When was the oil & filter last changed.? Was the suction screen removed & cleaned at the same time.?
Take up the floor plate and observe the drive shaft between the converter and the transmission. At low idle RPM the shaft should stop dead when you engage any gear. Does it.?

 

[Jr Kloulubak]

no slop in linkages and new selector cables with correct adjustments as per service manual, we've been using Mobil H68 hyd oil for many years. checked trans suction screen(it's clean), filter replaced two days ago....trans shaft doesn’t stop when in gear and low idle, help..

 

[Jr Kloulubak]

my serial number is #4GG04096

 

[Nige]

we've been using Mobil H68 hyd oil for many years.

That's a first. I've never heard of anyone using straight hydraulic oil in a Cat powershift transmission before basically because it doesn't contain the required friction modifiers.

The fact that the drive shaft continue to spin when you select any gear indicates that the transmission clutches are not engaging which in turn means a lack of oil pressure.

Is the problem of failing to engage gears more pronounced when the tractor is cold.? If so the pump suction side could potentially be sucking air.

Last question: Do you have an Operation & Maintenance Manual for the tractor.? If you don't then here is a Link to a brand-new genuine manual for $43.

 

[Jr Kloulubak]

okay Nige, let me talk to my mehanic about the suction side leakage possibility and thoroughly check it and do pressure test again to verify, thanks and will update you on the results.

 

[Nige]

I would suggest that you put a gauge on the pump pressure test port and observe closely what happens as you jiggle the transmission shift around.

I don’t think the oil you are using is helping matters but then again I don’t think it is the root cause of the problem either.

 

[Jr Kloulubak]

hi Nige, update on shifting problem , you hit the nail on the head!
oring was broken on pump suction, replaced it and now shifts good!
pump pressure gauge reading is steady and on spec, no more needle fluctuations and air in oil!! thanks a million Nige!

 

[Nige]

I'm glad that you found the problem but get some proper power train oil in it please, otherwise you'll be repairing a burned-out transmission sooner rather than later...........
Hydraulic oil doesn't work long-term in a transmission that requires TO-4 specification oil.

 

[Jr Kloulubak]

Yes consider it done, I told our mechanic to switch over to Shell Rimula X30 just for the powertrain from now on.

 

[Nige]

Yes consider it done, I told our mechanic to switch over to Shell Rimula X30 just for the powertrain from now on.

Rimula X30 is an engine oil..........

If you use Shell products then for a Cat transmission you need Spirax S4 CX 30. That is Shell's version of a TO-4 powertrain oil that meets Caterpillar Specification.



Attached the spec sheet - http://tdc.ge/wp-content/uploads/2014/03/7_SPIRAX_S4_CX_30.pdf