• Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

My 68 Cat D6C

Mcrafty1

Senior Member
Joined
Oct 12, 2019
Messages
441
Location
Central Maine
Occupation
Earth work
I was pushing debris from a land clearing job recently and the distance I was carrying the load was considerable, probably two acres...The day was hot but the machine wasn't showing signs of heating in either engine or torque converter. do to the distance I had to push I attempted to hurry the machine a bit by doing some of the distance in 2nd gear. I was doing this because I didn't see the need to run full RPM and thought that by pushing in second gear at around half throttle or a little more I would save some fuel and not work the old machine as hard. What happened was as the day warmed up and I had made many runs at one point the machine slowed and then stopped altogether but the RPM's didn't change. It appeared as though the torque converter gave up. I idled down and checked all the fluid levels and got back on the machine put it in 1st gear and it worked fine. After that experience I stopped pushing long distance in 2nd gear and the tractor work fine for the remainder of the job. I did a lot of hard pushing with it after the problem occurred but mostly in 1st gear it never slipped again, worked as it should. The tractor is the one in my sig and the serial# is 76A5579 All oil and filters are new and cat specs. What would cause this and what can I expect to see develop because of it? Thanks in advance for any help with this.
 

Tinkerer

Senior Member
Joined
May 21, 2009
Messages
9,342
Location
The shore of the illinois river USA
I think the engine should be run at full throttle all the time. It maximizes air flow through the radiator and keeps all the fluids flowing fast through their coolers.
I ran all sorts of dozer for a long time, and I do not ever recall having the engine overheat.
There is a mechanical problem about to rear its ugly head if you have to run in 1st to avoid "anything from slipping "
 
  • Like
Reactions: JPV

Mcrafty1

Senior Member
Joined
Oct 12, 2019
Messages
441
Location
Central Maine
Occupation
Earth work
I think the engine should be run at full throttle all the time. It maximizes air flow through the radiator and keeps all the fluids flowing fast through their coolers.
I ran all sorts of dozer for a long time, and I do not ever recall having the engine overheat.
There is a mechanical problem about to rear its ugly head if you have to run in 1st to avoid "anything from slipping "
Thanks for the reply, I wasn't running the tractor half throttle to avoid anything overheating, it was to conserve full and not push the old machine as hard, I never tried running the machine in 2nd at full throttle, maybe it wouldn't have did what it did if it had been running wide open? IDK, I guess I'll need to keep a close eye on things and see what develops.
 

nicky 68a

Senior Member
Joined
Apr 14, 2013
Messages
1,159
Location
england
Perhaps the 2nd clutch packs are worn and heating up abit?
I’m not a fitter,but sometimes transmissions would get 3rd gear clutch packs swapped into 2nd or 1st.
As for running at half throttle,I know what you mean as I’ve done it myself.I could have been kidding myself though
 

Mcrafty1

Senior Member
Joined
Oct 12, 2019
Messages
441
Location
Central Maine
Occupation
Earth work
Time will tell I guess, as good as it works now I wouldn't consider tearing it apart for any reason. I'm going to try using it wide open throttle and see if it does it again.
 

D5Dan

Well-Known Member
Joined
Sep 29, 2021
Messages
119
Location
Oxford, Maine
McCrafty next time it stops pushing like that lift up the center floor section (mine has a T-handle twist, aka- no tools needed to remove) to see if the driveshaft is still spinning... If it had stopped, then your torque converter would be the top suspect; if it had been spinning, then ur 2nd gear clutch packs would be the suspect.
I would also take an infrared temp gun to check various components to see if/what kind of heat is coming into play (kinda a “trust but verify” ur gauges). Especially the trans oil cooler up by the engine...maybe it’s not flowing correctly and caused ur 2nd gear clutch packs to heat up and get pissed off??
Of course the better stat to track would be some tranny pressures; but you’ll need the real mechanics to step in on that process...I’m not quite there on that procedure (nor do I have the gauges, yet...).
I assume your machine has the cleanable screen/magnet setup like mine...I’d pull that and look for fuzz and chunks...requires no replacement parts...but like my situation, might introduce more questions than answers?!?
Hopefully it’s just an operator “error” and ur old horse was telling you to smarten up ;))...
 

Mcrafty1

Senior Member
Joined
Oct 12, 2019
Messages
441
Location
Central Maine
Occupation
Earth work
McCrafty next time it stops pushing like that lift up the center floor section (mine has a T-handle twist, aka- no tools needed to remove) to see if the driveshaft is still spinning... If it had stopped, then your torque converter would be the top suspect; if it had been spinning, then ur 2nd gear clutch packs would be the suspect.
I would also take an infrared temp gun to check various components to see if/what kind of heat is coming into play (kinda a “trust but verify” ur gauges). Especially the trans oil cooler up by the engine...maybe it’s not flowing correctly and caused ur 2nd gear clutch packs to heat up and get pissed off??
Of course the better stat to track would be some tranny pressures; but you’ll need the real mechanics to step in on that process...I’m not quite there on that procedure (nor do I have the gauges, yet...).
I assume your machine has the cleanable screen/magnet setup like mine...I’d pull that and look for fuzz and chunks...requires no replacement parts...but like my situation, might introduce more questions than answers?!?
Hopefully it’s just an operator “error” and ur old horse was telling you to smarten up ;))...
Thanks for the reply, I have the tractor back home now and will check the screen asap, I cleaned the magnets off and replaced the outer section when i did the drain and fill I found nothing unusual when I changed that and all the other filters and oil. But that doesn't mean there isn't anything there now. I will follow up with what i find but I won't be on it for a while, too much work backed up for my other equipment. Thanks for the help. Also thanks for the idea of checking the drive shaft from the torque converter to the transmission, I hadn't thought of that. Maybe your are right about the old girl not liking the pushing without running full throttle. One can hope right?
 
Last edited:
Top