8spd trans heater bypass parts and cutaway view

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caulk04

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Many of you have purchased my bypass valve for the 8HP TMU, more recently I've made a new aluminum cap/plug to replace the stock plastic one that can be a bear to remove. Here's a little look at what happens stock, bypassed, and with the new cap.

Reach out if you have questions or would like to insure your trans against overheating with a bypass valve and aluminum plug. Products available here

PXL_20240802_161104358.MP.jpg


Red arrow shows the port where fluid enters the TMU from the trans.
Blue arrow shows fluid exiting the TMU manifold into the heat exchanger (heater)
Blue circle is heated fluid returning from heat exchanger which then reenters the trans
Green arrow shows fluid leaving the TMU manifold going to the trans cooler/ac condenser up front.
Green circle is cooled fluid returning from the cooler reentering the trans.

markup.jpg

This cutaway shows what's packed into this housing as factory, plastic cap and thermostat inplace (fluid routing to heater):

stock.jpg

Here you see the bypass valve installed. Fluid flows only through cooler circuit, heater circuit is blocked

bypass.jpg

Here you see the bypass installed WITH the new aluminum cap I'll have available shortly. No telling where the restriction in this system is now, but it is decidedly NOT here. MUCH more open in this arrangement.

bypass cap.jpg
 
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HEMIMANN

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Should have made a kit to swap an RFE for a ZF!
 

EagleChief

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How in the world am I just now seeing this?! I've been on this forum for years, and yet, somehow missed this thread. Good work, on coming up with this idea!
 

oldstyle17

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So, out of general curiosity.. What temp is too low for the trans? I have done this bypass but without the fancy aluminum plug.(which I may need now haha) But now I am getting a low coolant temp code and my trans in the summer ran beautifully at around 145-150 in the Texas heat. Now that the cooler weather is hitting my trans is lucky to get over 100-110 on my drive to work. Is that temp too low? or am I just over thinking this. I just dont want to destroy my trans and currently debating on installing a new heater. I also thought about installing a new heater and running it in the winter and once summer temps return, reinstalling the bypass for the hotter summer and heavier towing season.
 

Sherman Bird

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Love the HP calculator in the background!

I'm having engineering....flashbacks.
Take SLOW DEEP breaths in, and exhale sharply! A bag over your face may be required at times! Visualize Pascal's Law and Ohm's Law... Gently hum Alms..... Do Calculus in your head... that's it! ;) ;)
 

Sherman Bird

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Many of you have purchased my bypass valve for the 8HP TMU, more recently I've made a new aluminum cap/plug to replace the stock plastic one that can be a bear to remove. Here's a little look at what happens stock, bypassed, and with the new cap.

Reach out if you have questions or would like to insure your trans against overheating with a bypass valve and aluminum plug. Bypass valves available here Aluminum plugs are available direct through me, PM or email at [email protected]

View attachment 552091


Red arrow shows the port where fluid enters the TMU from the trans.
Blue arrow shows fluid exiting the TMU manifold into the heat exchanger (heater)
Blue circle is heated fluid returning from heat exchanger which then reenters the trans
Green arrow shows fluid leaving the TMU manifold going to the trans cooler/ac condenser up front.
Green circle is cooled fluid returning from the cooler reentering the trans.

View attachment 549137

This cutaway shows what's packed into this housing as factory, plastic cap and thermostat inplace (fluid routing to heater):

View attachment 549138

Here you see the bypass valve installed. Fluid flows only through cooler circuit, heater circuit is blocked

View attachment 549145

Here you see the bypass installed WITH the new aluminum cap I'll have available shortly. No telling where the restriction in this system is now, but it is decidedly NOT here. MUCH more open in this arrangement.

View attachment 549146
This is good info. I stock the kits for Ford and GM 8 speeds. Get them from TransStar. Can you IM with your info and price list?
 
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