I have a 1991 d8n dozer with the transmission heating up, was good this spring of 2024 until this month. Changed trans oil, filters and found a collapsed filter with chunks missing from the filter (middle). I see one of the lines I’m assuming that the flow heads to the transmission case on top and the other from the pump. I had cleaned the oil coolers x2, new water pump, thermostat, flushed the rad. When running the the machine it would heat up to the max 140*F on the trans gauge, the engine gauge 208*F. Once it put in neutral the trans cools down quick within 4 min to 75*C and engine down to 180*C. There was suppose to be 3 belts for the fan but only has 2. I’m thinking the chunks from the transmission filter is plugging something up. I will be checking the transmission control in morning also the three screens. Let me know if any of you can help me. Ty
Engine 180*F
Temps are not extreme depending on ambient temperature. Maybe check your top and bottom radiator temperatures with a temp gun to make sure you have good heat transfer.
Post a Serial Number please. If those numbers are correct (please confirm) then the problem is with the engine cooling system not the transmission. The high temp alarm for the transmission does not activate until 260 DegF. Even 208 DegF on the engine cooling system is not enough to set off the high temp alarm (from memory 220 DegF). A test best done when it's dark is to have someone in front of the machine shine a light through the radiator (remove the covers/rock guards first) and move it over the whole area while a 2nd person in the engine compartment looks at the radiator from the inside for areas where the light doesn't show - indicating an externally-plugged radiator core. Other possibilities. Worn belts, worn pulleys, defective fan belt tensioner. Post photos for opinions on their condition.
Serial number: 9TC04078
Found the part of the filter that was at the transmission control in the tube. Everything runs good but transmission over heats a bit because I’m short 5 gallons of oil 30w. Clean all screens and the belt/pulleys for fan are good. I can push hard for about 45 min than the mechanical gauge for engine shows 220*F and transmission around 122*C. Put it park it cools right down in 5 min. The dipstick shows 1/16” of the tip of oil so I know low oil would cause this. I don’t have access to the oil until tue. Life in remote areas.
Also found to small O rings broke off the speed clutch and directional clutch
With the engine running or stopped.?
With engine low idle. Can be checked stopped cold or low idle normal operating temp