2004 2500hd tranny fluid choice

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236
Location
In the field
I do some heavy towing here and there. What is the best option for shearing resistance and keeping the fluid cool? Will maxlife match amsoil or redline under heavy duty conditions? I was also looking at the mag1. Great price. Thx
 

ls1mike

$50 Site Donor 2021
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6,822
Location
In the Garage...
I have been using DEX 6 in my 2002 2500 HD for the past 3 years, 15,000 miles. Tow about 8000 lbs 3000 to 4000 miles a year. The 4L80E likes the DEX 6 or Dex 3.
 
Messages
5,651
Location
Iowa
Does yours have a factory cooler? My best friend has an 05 powered by the 6.0l with the cooler and gauge- and he regularly tows as much as 21,000 GCVW which would be 14,000+ lbs loaded trailer (truck 6500lbs) up steep hills, out of fields and 30+ miles to the hay market. The gauge almost never moves over 150* and all he ever uses is parts store labeled Dex 3. Truck has 175k and NEVER misses a beat.
 

Alltherage

Thread starter
Messages
236
Location
In the field
I have the cooler. I just changed the tranny oil cooler lines and it seems to get warmer than it did before. 140-150 not towing and 165-175 towing in summer. Normal temps based on my research. I have heard of full syn fluid staying cooler but who knows
 

ls1mike

$50 Site Donor 2021
Messages
6,822
Location
In the Garage...
What about long grades or big hills? Out here on the larger passes (8000 feet or 10 to 11 miles of 4 to 7 percent grade) with a large after market cooler I can see 200 to 210 for short periods of time towing close to 8000 lbs. I grew up in Catskill. NY and the hills there are not like out here in Washington state, so I am not sure I would be a good comparison. I know flat land towing I am right at 155 to 160.
 
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