RevMax 8 speed thermostat bypass

crazykid1994 said:

If you had the thermal management unit it would be super easy to create a piece similar to the thermostat that would just fit into the plastic cap, same as the thermostat, and reach far enough in to cover the rear hole. I think the factory thermostat just causes a restriction to the rear hole as there is no way for it to fully block it off by what I saw when I had it apart. You would need a thermal unit to make measurements though. A measured restrictor could actually work to keep the heater side functional to keep temps up but still allow more fluid through the radiator if that’s what was wanted. That’s actually why I’m sending caulk my thermostat. He is planning on creating a restrictor based off of the design of the thermostat in the fully open position.

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By rear hole you mean the bottom hole in the thermostat housing?


I am thinking a piece of pipe to use as a sleeve or cap off the bottom entirely with a solid piece of aluminium rod.

I would agree with Wild one. Block the flow of transmission fluid to the heater completely as opposed to trying for a blend or mix.
Am I understanding the physical characteristic of the heat sensitive thermostat and it's associated passageway correctly?
There are two openings in the side of the passageway that the thermostat is located in. Both on a lateral wall? One is deeper ( obviously LOL ) than the other. Actuallyy the deeper hole could in fact be in the bottom end of the passageway. The distal passageway if if left open will allow cooled fluid flow to the transmission. Blocking the proximal ( deeper ) hole would prevent transmission fluid from flowing to the heater. If the anatomy of the thermostat and the chamber it rides in is in fact what I am envisioning I now understand Caulk04's approach. Anyone with machining capabilities should be able to fabricate a "piston" to accomplish the goal. If the function of the passageways are reversed it may be a more difficult maneuver to accomplish.
Is this how the channel and thermostat are designed?

crazykid1994 said:

I agree with you 100% on that. Hence why I fully deleted the heater. My truck gets used for hauling and off-roading which is hell on the temps. My trans would get over 200° while off-roading which goes to show the factory thermostat is just a controlled restrictor. It does not shut the heater off completely.

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I'm not a fan of static controlled leaks,as they don't allow any give or take once things get hot. The thermostat restricts more of the bypass,the hotter it gets,which consequently sends more fluid through the cooler the hotter the fluid gets,while a static leak doesn't have the ability to restrict which way the fluid is routed when it gets hot.It's an either or situation with a static leak,no middle ground,while the thermostat has the ability to move the restriction for temperature changes

Different Drummer said:

I would agree with Wild one. Block the flow of transmission fluid to the heater completely as opposed to trying for a blend or mix.
Am I understanding the physical characteristic of the heat sensitive thermostat and it's associated passageway correctly?
There are two openings in the side of the passageway that the thermostat is located in. Both on a lateral wall? One is deeper ( obviously LOL ) than the other. Actuallyy the deeper hole could in fact be in the bottom end of the passageway. The distal passageway if if left open will allow cooled fluid flow to the transmission. Blocking the proximal ( deeper ) hole would prevent transmission fluid from flowing to the heater. If the anatomy of the thermostat and the chamber it rides in is in fact what I am envisioning I now understand Caulk04's approach. Anyone with machining capabilities should be able to fabricate a "piston" to accomplish the goal. If the function of the passageways are reversed it may be a more difficult maneuver to accomplish.
Is this how the channel and thermostat are designed?

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This is my take away on this but still looking to confirm.

3 holes. Top hole is radiator. Middle hole is the feed from the transmission. The bottom hole is to the heater. Yes blocking the bottom most hole would work. If someone made a plug to completely cover the bottom hole from inside the tstat housing would be the easiest and cleanest way to do the entire job and would negate everything Wild one and I have had to do. It would be super easy to measure and design a plug with 2 o rings to fit in. I debated filling the actual spot with jb weld putty instead of doing the heater plate but not sure how the putty would have done in atf.

Wild one said:

I'd be a little gunshy on trying to restrict the bypass...

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I mentioned this before but it's gotten lost. What I plan to make will make the cooler/heater operate as if the fluid is hot (thermostat open) at all times. However the OEM has designed the cooler to operate as far as flowing/blocking fluid in either circuit at full temp is how it will function at all times.

I haven't had the opportunity to fully examine one of these heater units, but I'd venture a guess that by simply removing the thermostat as revmax describes in their instructions you're allowing the fluid to follow the path of least resistance. I'd also imagine that doesn't put much fluid through the cooler. That's just my thoughts.

Stand by, once I get the thermostat in my hands I'll make up a prototype and get it installed pretty quick. I'll know very quickly if it takes the heater out of the equation.

Transmission is filled. Took 1/2 a quart to start coming back out of the fill hole after going through the sequence. Pretty easy to do and now I know for future. Would like to upgrade to the bigger aluminum pan in the future if it’s still available. It definitely takes a lot of lift to get the trans pan level.

crazykid1994 said:

3 holes. Top hole is radiator. Middle hole is the feed from the transmission. The bottom hole is to the heater. Yes blocking the bottom most hole would work. If someone made a plug to completely cover the bottom hole from inside the tstat housing would be the easiest and cleanest way to do the entire job and would negate everything Wild one and I have had to do. It would be super easy to measure and design a plug with 2 o rings to fit in. I debated filling the actual spot with jb weld putty instead of doing the heater plate but not sure how the putty would have done in atf.

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Got it! Plug the most proximal ( bottom ) channel, Cooled fluid arrives from cooler via Distal ( top or outer most ) channel and exits through the medial ( middle ) channel directly to the transmission.
Sounds good. The outer two channels must be in a lateral wall. Is the deepest channel ( the one that needs to be blocked ) in a lateral wall also? Or is it directly in the bottom of the channel?

caulk04 said:

I mentioned this before but it's gotten lost. What I plan to make will make the cooler/heater operate as if the fluid is hot (thermostat open) at all times. However the OEM has designed the cooler to operate as far as flowing/blocking fluid in either circuit at full temp is how it will function at all times.

I haven't had the opportunity to fully examine one of these heater units, but I'd venture a guess that by simply removing the thermostat as revmax describes in their instructions you're allowing the fluid to follow the path of least resistance. I'd also imagine that doesn't put much fluid through the cooler. That's just my thoughts.

Stand by, once I get the thermostat in my hands I'll make up a prototype and get it installed pretty quick. I'll know very quickly if it takes the heater out of the equation.

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If it accomplishes what I describe in post #328 I am all in for one.

Haven't heard anyone use proximal/distal since I had my busted up hand fixed a few years ago...

I can't confirm what you're saying because I don't know what each passageway does. But the mechanics of the cooler/heater will basically think the fluid is full hot all the time with the part I'll be making. I'd assume that that means the engine coolant would not interact with the trans fluid and that it would flow through the cooler up front at all times.

@Different Drummer hope this helps clarify. You can see all the passageways and how they line up.

The bypass hole to route fluid to the exchanger is the very bottom hole in the inlet side bore,then there's a return feed hole in the return side of the unit,as you can see by CK's pic above. Both holes tie into the main body of the unit. The plate is the easiest way to block off both holes. The thermostat side of things would need a block off plug fairly long to block the bottom bypass hole,and would need to be shaped to still allow fluid to bypass to the cooler,definitely not an impossibility but it would require a fancy plug to block the bottom hole while still letting fluid flow to the cooler holes farther up the bore.To me it'd be far easier to duplicate the Rev Max plate and just take the stock thermostat out of the equation.Anybody with a water jet cutter can duplicate the plate.

Bypass hole is the bottom hole in the side

It is amazing how similar the actual heat exchange unit looks like some fresh water boat cooling units I have worked with. Same shape and size. In the boats raw sea water is pumped to the heat exchanger where it cools the recirculating antifreeze mixture used in the engine. The raw water is then eliminated overboard through the exhaust.

I am not sure I like the plate deal. Seems leak prone to me. For your needs I like what you guys are doing with the total elimination of the heat exchanger and associated components.

For us seeking to go the inside passage so to speak, I envision a machined aluminum smooth plug on the end of a rod. The plug blocks the passageway to the heat exchanger and the rod seats into the end cap that is held in place with the C-clip. (The distal end, LOL) This would hold it in place. I don't see the need for any type of sealing devices like o-rings. Just a nicely machine fit should be adequate. Looks like the case is aluminum so by using aluminum you would not have dissimilar metals in play. The rod holding it in place shouldn't be any more restrictive to flow than the OEM rod and spring. When I say rod I picture it as being part of the plug. All being machined from one piece, not two separate pieces. Or, I suppose you could just place a spring in the bore to keep the plug bottomed where it needs to be and eliminate the rod portion. That would make the machining of the plug easier. The bottom bore looks smaller than the upper bore. I don't think I would trust it just sitting down in there without something holding it in though.

I'll defer to Grizztang and Caulk04 on the design. Sounds like they have some machine shop or maybe tool and die making experience.

I think Caulk would need the whole unit,not just the thermostat. The thermostat seats against the top of the stepped hole in the bore,so to get the right length and diameter to build a plug that drops into the barrel of the bottom bore he'll have to get a diameter off the stepped bottom hole,and he'll have to measure up from the bottom of the bore for the length.The thermostat uses the bottom plate of it's design to seal the bypass hole off.I'm not sure if having just the thermostat to duplicate will give enough data to build the bore plug

If you go back to post 136 ,then compare to the inside pic of the bore in the pic on post #333,you'll see how the bottom plate of the thermostat seals against the machined lip of the top of the bottom bypass hole,that's why i think Caulk would need the whole unit,and not just the thermostat itself

Wild one said:

I think Caulk would need the whole unit,not just the thermostat. The thermostat seats against the top of the stepped hole in the bore,so to get the right length and diameter to build a plug that drops into the barrel of the bottom bore he'll have to get a diameter off the stepped bottom hole,and he'll have to measure up from the bottom of the bore for the length.The thermostat uses the bottom plate of it's design to seal the bypass hole off.I'm not sure if having just the thermostat to duplicate will give enough data to build the bore plug

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Oh, I agree. Proper measurements with the proper equipment would be ideal.
At any rate, the housing in ones hands would be the appropriate approach. Too bad we did not think of this when you and Crazykid had yours off. Inserting the shank end of a drill bit into the bores of the passageway would have been an easy way to measure the bottom bore and the larger bore above it. The depth of the bottom bore could be determined even in the absence of a properly designed measuring device for the job. It would not be terrible difficult to make a rudimentary depth gauge for the job.
Looks to me like any method used to reliably block off the lower smaller bore would accomplish what is being suggested.

Just a rough drawing for concept.

Different Drummer said:

Oh, I agree. Proper measurements with the proper equipment would be ideal.
At any rate, the housing in ones hands would be the appropriate approach. Too bad we did not think of this when you and Crazykid had yours off. Inserting the shank end of a drill bit into the bores of the passageway would have been an easy way to measure the bottom bore and the larger bore above it. The depth of the bottom bore could be determined even in the absence of a properly designed measuring device for the job. It would not be terrible difficult to make a rudimentary depth gauge for the job.
Looks to me like any method used to reliably block off the lower smaller bore would accomplish what is being suggested.

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I never even thought to measure the depth of the bore when i had mine apart.It would of been easy enough to do to,with a set of vernier calipers.That's a ***** on my part,aarrgghh,lol.
BTW :you're a hell'va artist,lol

Can anyone indicate the fluid flow direction on these ports? I'm curious on the in/out and flow direction.