8hp70 heater bypass

hawsk99gt · Jun 2, 2021

Hey as long as it is not hotter than my engine oil I am fine. I didn't want to do what FCA would want me to do and sit on it till the transmission burned up, again.

MRFREEZE57 · Jun 2, 2021

Wild one said:
The cars and heavy duty trucks don't pre-heat the tranny fluid,and they work fine in the winter.My wifes 2019 6.4 Challenger will take 50 miles to warm up to 110F with outside temps 30/32F if you're not beating on it.I can go to the city and back with it on a day where the outside temps are high 20's low 30's and it might get to 100F on the tranny temp.I'm in Alberta,little north and east of you,and you guys get mild winters compared to us,lol

I do see temps up as high as 188 deg when in traffic, that is with a PPE pan and the exhaust wrapped.
that is higher than I would like to see, seems they should have used a 150deg stat, stat would be better than the 180. I am thinking may order CAULK4's bypass as it appears very simple to install. would think in colder temp that the shutters would aid in warming up the fluid.

Musky Mike · Jun 3, 2021

MRFREEZE57 said:
I do see temps up as high as 188 deg when in traffic, that is with a PPE pan and the exhaust wrapped.
that is higher than I would like to see, seems they should have used a 150deg stat, stat would be better than the 180. I am thinking may order CAULK4's bypass as it appears very simple to install. would think in colder temp that the shutters would aid in warming up the fluid.

Just remember, you can remove grill shutters, go to a lower engine T-Stat, but it will do little for engine temps in traffic on a 5th gen, because there is no mech fan and the electric fan is set to come on over 200 (I forget the temp, 206 I think), so no air flow until the electric fan comes on.

caulk04 · Jun 3, 2021

https://drive.google.com/file/d/1Hw94YEMSg99wLGll5PliQ0KuWKToqSB6/view?usp=sharing

Finally wrote up a little better install info for those interested.

caulk04 · Jun 3, 2021

MRFREEZE57 said:
...seems they should have used a 150deg stat...

I wholeheartedly agree. I looked around quite a bit and couldn't find any commercially available thermostats to use.

HvyDuty · Jun 3, 2021

Hmm, maybe installed it backwards? Should I worry about a couple more ounces of fluid lost when I check?

Gonna wrap the crossover pipe when I’m back under there.

Wild one · Jun 3, 2021

caulk04 said:
I wholeheartedly agree. I looked around quite a bit and couldn't find any commercially available thermostats to use.

If you can cut and flare lines,one of these could be plumbed into the cooler lines. I've thought about using the 145 degree version for awhile now,just my cheap ass hasn't gotten around to ordering one,i'm Canuck,so i basically double the listed US price,by the time it's sitting on my doorstep.

High-Flow Engine & Transmission Oil Cooler Thermostat (improvedracing.com)

caulk04 · Jun 3, 2021

HvyDuty said:
Hmm, maybe installed it backwards? Should I worry about a couple more ounces of fluid lost when I check?

Gonna wrap the crossover pipe when I’m back under there.

I'd say you're likely fine, but if it were me I'd get a quart of fluid and do the procedure to check level. I'm also a very curious person.

I've been wondering off and on the last few days about your situation and was considering asking you to send me your stock thermostat to inspect and measure. You were also part of the reason I refined and expanded on my instructions.

caulk04 · Jun 3, 2021

Wild one said:
If you can cut and flare lines,one of these could be plumbed into the cooler lines. I've thought about using the 145 degree version for awhile now,just my cheap ass hasn't gotten around to ordering one,i'm Canuck,so i basically double the listed US price,by the time it's sitting on my doorstep.

High-Flow Engine & Transmission Oil Cooler Thermostat (improvedracing.com)

I remember these being brought up before. The problem with it for me is the same as my reasoning behind making my part. I didn't want to physically modify any of the factory parts.

Wild one · Jun 3, 2021

caulk04 said:
I remember these being brought up before. The problem with it for me is the same as my reasoning behind making my part. I didn't want to physically modify any of the factory parts.

Mines well off warrenty,so that part doesn't bother me much,it's my cheap ass that doesn't want to spend the money to buy the aftermarket thermostat,lol :waytogo:

hawsk99gt · Jun 3, 2021

real quick what color should the transmission oil be? When I was doing the CAULK4's bypass procedure and the oil that leaked out was clear. Wanted to make sure that my stealership put in the correct oil.

Wild one · Jun 3, 2021

hawsk99gt said:
real quick what color should the transmission oil be? When I was doing the CAULK4's bypass procedure and the oil that leaked out was clear. Wanted to make sure that my stealership put in the correct oil.

Basically it's clear,or has a very light greenish tint,and is about as thick as water,lol

hawsk99gt · Jun 3, 2021

Wild one said:
Basically it's clear,or has a very light greenish tint,and is about as thick as water,lol

OK sounds like the right fluid. Thanks! And it taste like cactus juice.

Wild one · Jun 3, 2021

hawsk99gt said:
OK sounds like the right fluid. Thanks! And it taste like cactus juice.

Can't comment on the cactus juice,i'm Canadian,so i've never tasted Cactus juice,lol

HTXRamExp · Jun 15, 2021

I'm interested in doing this mod for my 2019 classic. I'm down in Houston and temps are up the majority of the year, so no real concern with cold weather conditions.

Also looking into a Stant 180* thermostat and removing either the middle AGS slats or the system completely with the delete kit.

Being I am not tuned and have both OEM fans still installed, would this have any undesired effects?Should I just hold off until I get a tune for the truck?

Sent from my iPhone using Tapatalk

caulk04 · Jun 16, 2021

The only things I've done to my truck is pull the AGS slats out and install my thermo bypass. No need for a tune, even if you do install a lower temp coolant t-stat.

HTXRamExp · Jun 16, 2021

caulk04 said:
The only things I've done to my truck is pull the AGS slats out and install my thermo bypass. No need for a tune, even if you do install a lower temp coolant t-stat.

PM sent.

Sent from my iPhone using Tapatalk

MRFREEZE57 · Jun 17, 2021

received my bypass valve from caulk, looks to be a very well made part, just have not got around to installing yet.

HvyDuty · Jun 22, 2021

I’d like to update the results in my 5th gen now that it’s been a couple weeks with caulks modded tsat.
My transmission does run cooler now overall. It takes several more minutes for it to warm up.

Being a 5th gen, my truck does not have the mechanical fan and what I’ve found is that if I run my ac the electric fans kick on and help in keeping my trans temps no higher than 185

Sitting in traffic without ac on, temps will creep up to 199.

My cooling mods:

-caulk tstat
-grille shutter mod (only two slats)
-exhaust crossover wrap

I wonder if I can retroactively install a mechanical fan? Lol

crazykid1994 · Jun 23, 2021

HvyDuty said:
I’d like to update the results in my 5th gen now that it’s been a couple weeks with caulks modded tsat.
My transmission does run cooler now overall. It takes several more minutes for it to warm up.

Being a 5th gen, my truck does not have the mechanical fan and what I’ve found is that if I run my ac the electric fans kick on and help in keeping my trans temps no higher than 185

Sitting in traffic without ac on, temps will creep up to 199.

My cooling mods:

-caulk tstat
-grille shutter mod (only two slats)
-exhaust crossover wrap

I wonder if I can retroactively install a mechanical fan? Lol

May need to install a fan on the transmission cooler to help but that definitely seems very odd that it’s hanging out that high.

8hp70 heater bypass

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