04.5 LLY Built Suncoast Running Hot?

[04LB7yz]

So I have a 2004.5 LLY with a Built tranny using suncoast parts and a precision converter. Tranny has probably 35-40K on it and has been in two trucks. It came out of my 2004 LB7 after I wrecked it. When it was in my LB7, temps never really rose above 170 while towing heavy or beating on it at any temp outside. My LLY under normal driving conditions will creep on 210 on a 75 degree day if i have been driving for a while. Say sitting in traffic or something like that. Why is it that it runs so much hotter in my LLY? Is this something that i should be concerned about? Will an aftermarket cooler solve the high temps? Any help is greatly appreciated!! :thumb:

 

[Mike L.]

So I have a 2004.5 LLY with a Built tranny using suncoast parts and a precision converter. Tranny has probably 35-40K on it and has been in two trucks. It came out of my 2004 LB7 after I wrecked it. When it was in my LB7, temps never really rose above 170 while towing heavy or beating on it at any temp outside. My LLY under normal driving conditions will creep on 210 on a 75 degree day if i have been driving for a while. Say sitting in traffic or something like that. Why is it that it runs so much hotter in my LLY? Is this something that i should be concerned about? Will an aftermarket cooler solve the high temps? Any help is greatly appreciated!! :thumb:

You may have a partialy restricted heat exchanger or cooler.

 

[04LB7yz]

Alright, I will check that out and see if its blocked. Would it be beneficial for me to put an aftermarket cooler on it on it? Also what is considered too hot? I've done quite a bit of research on it and everyone seems to have their own idea on it. At what temp will the Alison start to self destruct? Thanks for the help!

 

[ikeG]

My lly did this when I had overfilled the trans.

 

[A. Stock Lbz]

My lly did this when I had overfilled the trans.

I over filled mine by 3/4 of a quart and did this also. It dropped 10-15 deg when I filled it up rite.

 

[SoCalMike]

If you run dex3, at 240/250f the additives will break down and the fluid will be trash..

 

[catman3126]

why does over filling them make them run hotter? what does it do?

 

[TheBac]

why does over filling them make them run hotter? what does it do?

Ive always wondered that myself.

 

[WolfLMM]

Well I'm not a trans expert, but overfilling any hydraulic system can lead to foaming. As fluid heats up it expands.... That's "why" there is a vent on the top of the trans, to give the fluid a path to escape.

 

[Mike L.]

The fluid rises high enough to be caught in the turning gear train. PTO gear or tone wheel on the front rotating assembly which will cause churning of the fluid and heat.

 

[TheBac]

Thanks Mike.

 

[Rancelot211]

Mike how much does one of your coolers run for an lmm.

 

[04LB7yz]

Thanks guys! My fluid level is a little on the high side.. Not by much but i will take some out and see what happens. What temp is considered "hot" for an accurate reading on the dipstick? I have always wondered this because the level changes as the tranny temp gets hotter or colder.

 

[SoCalMike]

Thanks guys! My fluid level is a little on the high side.. Not by much but i will take some out and see what happens. What temp is considered "hot" for an accurate reading on the dipstick? I have always wondered this because the level changes as the tranny temp gets hotter or colder.

At 175f (transmission temperature) the fluid level should be at the middle of the lower hot hash mark. This is what my builder has told me.

I just make sure at operating temp or as close as I can get it to 175f, the fluid level is in the middle of the "hot" section of the dipstick.