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H3 Alpha trans temp

fowlken8

Well-Known Member
Messages
246
Location
Southwest
And now I cannot edit my posts. Whatever. Anyways I'm aware that the 5.3 and the 4L60E tend to run warm but don't know if I should be concerned. Yesterday was mid 90s, had my A/C on. Traffic here just sucks, stop and go for 30-45 minutes. The scangauge showed that the trans temp got up to 204, it didn't climb any higher. The engine temp also hit 204 which I'm not too worried about given the outside temp, A/C and traffic. The trans takes a while to warm up from what I've seen, but once it does it just climbs to just over 200. I don't have a standalone trans cooler. I'm on 35s.

I'd like to know if those numbers seem ok? Want this sorted out before pulling the trailer next month. I'd hate to ruin the Alpha pulling up all the crazy grades around here, luckily the trailer weighs 3100 lbs.
 

JPaul

Well-Known Member
Messages
2,394
Location
Way up north, UT
With a stock cooling setup, yes that is normal. The trans cooler is built into the radiator so it will at least get as warm as the coolant temps after a while. To keep the transmission cooler you need to either add a secondary cooler after the radiator or switch to a standalone cooler entirely. Just need to make sure it is a large enough cooler since air to liquid coolers are less efficient than liquid to liquid.

I personally went with a Tru-Cool LPD 4590 cooler. It's rated for 28,000 lbs GVW but is less than 12 inches square. I also ended up adding a thermal bypass so that until the transmission reaches 180* it won't go through the cooler and just loops back in. Once it reaches temp the bypass opens and lets fluid flow through the cooler.
 

JPaul

Well-Known Member
Messages
2,394
Location
Way up north, UT
Ouch, just checked prices on the LPD 4590. I bought mine in 2019 for $84 shipped. They've more than doubled in price since then apparently, if you can even find them. Lot's of Chinese knock-offs out there of the Tru-Cool coolers, so be careful.
 

Doc Olds

Well-Known Member
Messages
113
Location
Boat Town MI
When was the last time you changed the Trans Fluid and Filter?

I would call 204F all of 4F over normal and maybe 14F over preferred, so no need to freak out.
 

fowlken8

Well-Known Member
Messages
246
Location
Southwest
I've been watching my temps closely. My engine and transmission hit 200+ regardless of highway vs stop and go driving. Unsure how normal this is, but my engine temp needle never gets past halfway. Just don't want to fry anything next month. Luckily I'm only pulling 3k lbs.
 
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