| Author | Message | ||
| Roy Childs (Rchilds)
Registered Member Username: Rchilds Post Number: 4 Registered: 5-2007 Posted From: 75.160.168.201 Rating: N/A |
Can anyone explain where the Dextron fluid is going. I am adding about a quart everry 150 miles. No visible drips on the ground... Thanks, Roy The engine coolant is not oily, just checked it. (Message edited by rchilds on May 19, 2009) | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1072 Registered: 12-2000 Posted From: 71.3.157.139  Rating: N/A |
Check the engine coolant. Does it appear "oily"? If so, you have a leak in the transmission cooler that is on the side of the engine. That is the only place I can think of where fluid could go without dripping on the ground somewhere. Jack | ||
| Roy Childs (Rchilds)
Registered Member Username: Rchilds Post Number: 5 Registered: 5-2007 Posted From: 75.160.168.201 Rating: N/A |
The engine coolant isn't oily. Just checked it | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 829 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
Roy, I think Jack is in the right church, just the wrong pew. Assuming your trans cooler is a dual cooler, (engine and trans oil) mounted on the side of the block, any chance your trans fluid is getting into the engine oil instead of the coolant? How much, if any engine oil are you adding, and did your oil consumption go down when the problem started? If you have only an oil-to-air cooler, our suggestions are OFF. Happy hunting, G | ||
| david moody (Buzzincuzzin)
Registered Member Username: Buzzincuzzin Post Number: 8 Registered: 3-2009 Posted From: 68.35.242.57 Rating: N/A |
That is an enclosed hydraulic system. If you're losing ANY fluid it's a potential major problem. Have a pro take a look ASAP. | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 220 Registered: 2-2007 Posted From: 207.200.116.13 Rating: N/A |
Check the vent. A quart is not alot if its not going into the engine or obviously leaking. Does it go lower than 1 quart or will it hold at 1 quart? Mine is as full as it will hold without throwing fluid out when hot and is under the high mark unless its real hot. Your system holds gallons and needs room for expansion. An example is my cooling system that holds about 23 gallons. When cold, I can top off the expansion tank all the time with almost a gallon, but if I just leave it alone it rarely goes more than a gallon low. My HTB 748R will throw out what it doesn't want when I stop it when hot and do my cool down at high idle or even idle speed, so look on the ground and see if this is whats going on. If it is, recalibrate you high mark for further reference. The filter is also sensitive to pin holes and losing its seal. It is a high pressure filter and needs regular service. They also get rusty on the outside and develope leaks over time. Make damn sure that you get the right one, an oil filter may fit, but they won't hold the pressure. If you have to pull the cooler down take a real good look at the old and new gaskets, they are not all the same even though they look like it at first and if they are not replaced exactly, you will have big problems. | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1074 Registered: 12-2000 Posted From: 71.3.157.139 Rating: N/A |
As far as replacing gaskets, once again have the transmission and engine serial numbers with you when you go to DD or Allison. I took my 8V71 serial number to the local DD to order a couple engine gaskets and told them I also needed a pan gasket for an Allison 740 transmission. The first thing he said is "we need the transmission serial number". I said "all I need is the pan gasket". He said "there are several different pan gaskets, we need the serial number to get you the correct gasket". Jack | ||
| David Dulmage (Daved)
Registered Member Username: Daved Post Number: 247 Registered: 12-2003 Posted From: 61.10.5.98  Rating: N/A |
Check to make sure your transmission fluid filter is tight. It is external to the transmission. DaveD (Message edited by DAveD on May 20, 2009) | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 779 Registered: 10-2006 Posted From: 76.194.80.204 Rating: N/A |
If you still cant find the leak, NAPA sells florescent oil you can add to the tranny oil. A special flashlight and set of goggles and the oil is about $50. Far cheaper than a R&R + rebuild on the tranny. FF |