Transmission temperature 10speed with 3.0 LZO Duramax

[newdude]

4 hours ago, Rick_ said:

So you are saying that there is a water to oil transmission fluid "heater" along with an air to atf heat exchanger?  Where do I get hold of a diagram/microfiche of that routing?   Is the water to oil cooler a bar plate job between the trans thermostat and the air to oil cooler?

In the 2022 10L80/90? valve body there is a valve called the Cooler Thermostat Valve that gets modded to eliminate regulation to the flow to the cooler.  There are two styles - the 2022 has no brass thermostat, but later versions seem to have it.

Testing today after the valve body kit install, zero change in gauge temp unloaded - 180F at 84*F unloaded, so the atf heater is doing its job.   The positive so far is the lag in shifting from R to D has been eliminated.

 

There is a brass "thermostat" in the Cooler Thermostat Valve that is removed with the NextGen kit for the 10L1000 - 135F gauge temp with a 5000lb boat in small rolling hills at 85*F.   

 

 

The exchanger is bolted right to the driver's side of the transmission.  Would I go as far as to call it a heater?  No.  Does it aid in warming up the ATF to reduce friction as quickly as possible?  Yes.  What's the internals to it?  No idea.  Never cut one open.  

 

However, it's primary role is maintaining transmission temperatures once up to temp.  No different than an oil to water exchanger for an engine oil cooler setup like GM uses on say 2010-2024 Camaro with V8, or 6.6 Duramax.  

 

 

Gas 10L80s (so 1500 truck with gas V8) have a thermostat in the valve body but not the cooler lines.  2019-current.

 

3.0 Duramax with 10L80 don't have a thermostat in the valve body.  They have one in the lines going to the auxiliary cooler.  2020-current.  
 

[PunchT37]

Mine runs 145 to 158 ,95% of the time. ‘25 1500 with 5.3 and nht option. Wonder how long it will last? Wonder how much water is in the oil? Bought it in Oct 2024. 
 

This was today in south Louisiana. 

[newdude]

11 hours ago, PunchT37 said:

Mine runs 145 to 158 ,95% of the time. ‘25 1500 with 5.3 and nht option. Wonder how long it will last? Wonder how much water is in the oil? Bought it in Oct 2024. 
 

This was today in south Louisiana. 

 

 

 

That's the proper range for the gas 10 speed with the thermostat still in the valve body.  TBV opens at 143F.

 

3.0 Duramax runs different temp. 

Edited Friday at 02:24 PM by newdude

[Rick_]

I traced the atf cooling system in my 1500 and it comes out of the transmission, into the bar/plate liquid/liquid heat exchanger, as stated above.  Then it crosses over to the external thermostat/bypass and then  to the aux cooler in front of the main radiator.  Hence, on this routing, the PPE thermostat bypass eliminator is an $85 piece of bling that does nothing for reducing atf temps on this truck.  I think I'll temporarily clamp a needle nose vise grip on the coolant feed hose to the bar/plate cooler and see how much the atf temp drops.  With the use of ULV trans fluid, I'm not convinced running the trans cooler than OEM spec is going to be detrimental to the life of the transmission.   
I found this interesting on the Dana/Long site stating that they make transmission cooling/heating bar plate heat exchangers.  I worked with Dana/Long on a few projects when I was at the gas powered fun factory. https://www.dana.co.jp/downloads/PTG/Long/Dana_TOC_SpecSht.pdf  Bar plate heat exchangers are just a stack of stamped parallel path fluid channels, assembled and vacuum furnace brazed to make the final assembly.  Want more cooling/heating, just stack more plates until you run out of package space.  
Anyway, thanks for the info, much appreciated.