TJC
Well-Known Member
- First Name
- Tony
- Joined
- Aug 28, 2020
- Threads
- 45
- Messages
- 3,930
- Reaction score
- 9,840
- Location
- North Carolina
- Vehicle(s)
- 93 Miata, 05 Ranger 4x4, 20 Ranger 4x4, 23 CX-5
- Thread starter
- #31
It is indeed in the valve body. It is one of two temperature control points. The other is the external coolant valve that supply heated coolant to maintain transmission fluid temps at 195F. Racers pull the internal valve body thermal bypass out. I think it may be overkill for normal everyday trucks.Correct me if I am wrong but isn’t the thermal bypass on our transmission mounted inside, possibly the valve body? I know the 1/2 tons and up are or were externally mounted so removing them was easy.
I 've been monitoring my transmission behavior and fluid temps for going on 6 months. And I agree with the assessment that the transmissions behaves best at 150F- 165F.
But I want to be able to control the temps from inside the cabin. I can do that with a larger cooler and digital fan controller where I can dial in temp ranges until I find the optimal setting. I also want the ability to manually turn the fan on from inside the cabin. My digital controller does just that.
Mounting in the front of the truck doesn't allow room for the fan. It would be a passive system, and I'd have no control over the temps. It may over cool on the highway, and under cool in stop and go traffic.
This played a major role in my decision to go with the electric fan option. That and I can mount it most anywhere. Derale has some beautiful units. I'm building a clone of their systems, including the plenum/ mounting points. The aim is to add a skid plate under the drivers side rail up to the transmission brace, and mount the cooler assy on the top side of the skid plate, protecting it from water and debris. I'll run the lines from the transmission down the rail using the existing locking points along the rail above the skid plate to the cooler. It is a close fit at the transmission interface, where the transfer case front driveshaft goes to the front axle.... but I think there is room enough. Having the lift helps a bit. But those hoses just behind the oil filter are a bear to reach. You can also access the heat exchanger bolts and hoses from the same access area, but it is a tight fit.
On my first pass I may plan to pinch off the two hoses going to the heat exchanger, remove them from the heat exchanger and join them via a brass fitting to keep the flow circuit intact. I'll then remove the heat exchanger and install the AN8 hoses from the external cooler to transmission port and test/tune to see how well it functions.
If all goes well, I'll remove all the unnecessary hoses and block off the coolant valve. It will free up a great deal of space in that area.
That's my vision. We'll see how it goes. I'm going to bleed all over getting in there.... bonding with my truck!

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