RevMax 8 speed thermostat bypass

[crazykid1994]

I'd do exactly what I did with my Harley.

Heat the thermostat up and take measurements of it when it opens up. Then make a solid plug (likely aluminum) that copies those dimensions. This way, the cooler/heater operate exactly as the factory designed it to when the trans is HOT. It would just trick the mechanical components into thinking it's hot all the time, if that makes sense.

If anyone isn't clear on how that thermostat works, the small plunger that fits down into the plastic plug will extend as the thermostat gets hot and opens, that pushes all the other parts down into the body of the heater which will open/close passages. I've not had my hands on one to see how they open/close and what the fluid paths are to see just how the flow is designed.

That was sort of where i was going with defeating the pellet thermostat and extending the pin,only cause i don't have access to the tools to make a dummy plug,lol. I think you have a great idea Caulk. Khristopher would you be up to sending him your thermostat.

I can send it to you but at this point I don’t need the dummy plug since I have the blockoff plate installed. PM me and we can talk

 

[caulk04]

Here's a photo of the stock thermostat and the plug I made for the bike. It's much smaller than what you'd find in the truck, but the same concept applies.

 

[Wild one]

A few pics

 

[Wild one]

I deleted the heater completely.Tapped the bypass holes and JB Welded in some 5/16's plugs into the bypass holes,sure cleans up the side of the tranny.Also looped the coolant hoses on top of the transmission together . Once you disassemble the unit,it's pretty easy to see how they route the coolant through the heater and how the fluid bypass is routed. Only took a couple evenings to clean it up,lol



Bypass holes plugged





These are the updated transfer tubes,with-out the O-ring on them. I'm not sure when FCA updated these tubes,but i think anything newer then 16 probably has these tubes instead of the earlier leak prone O-ring versions

 

[crazykid1994]

When I do a pan and fluid at 50,000 I’ll be going that route. Looks so much better. Should share that to FB as well. Then I can fully delete the heater hoses too

 

[grizzstang]

I am interested in plugging the passage in the thermostat hole that goes to the heater. I am just not sure what hole needs to be blocked or how to block it yet. Maybe even just make that hole smaller somehow so the bulk of the fluid will flow through the cooler.


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[Wild one]

I am interested in plugging the passage in the thermostat hole that goes to the heater. I am just not sure what hole needs to be blocked or how to block it yet. Maybe even just make that hole smaller somehow so the bulk of the fluid will flow through the cooler.


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Hang on a week or so Shaun,i have some stuff being made by Aaron Machining,should be done by next Friday,then look me up.
Rick

 

[Wild one]

When I do a pan and fluid at 50,000 I’ll be going that route. Looks so much better. Should share that to FB as well. Then I can fully delete the heater hoses too

I've been wanting that damn heat exchanger gone for awhile Khristopher.Every time i had to do something under the truck,it pissed me off,lol. Just looking at it,made me perturbed,even if it wasn't in the way.Worst of it is the thermal unit is actually made in Canada,aarrgghh,lol

 

[crazykid1994]

Great news. Had a chance to take the truck out tonight. Truck was fully warmed up. I didn’t have the ac on so the radiator fan was on low. 75° out. Trans got to 132° after 30 or so minutes of driving. Will have better info next weekend for sure but the results are definitely promising.

 

[Different Drummer]

Man! You guys are moving at light speed! That'll teach me the perils of getting busy and going AWOL for a couple of days!
I was thinking of the idea of just eliminating the whole heat exchanger thingy and doing the required re-plumbing to put the rectangular block in service that the HD truck use. Looks like Wild one has pretty much accomplished that by using half of the Thermal dingus to secure the o-ring tubes into the Tranny by plugging the radiator coolant openings. Great work guys, I am sponging it all in for when my warranty has gone by-by.

 

[Wild one]

Man! You guys are moving at light speed! That'll teach me the perils of getting busy and going AWOL for a couple of days!
I was thinking of the idea of just eliminating the whole heat exchanger thingy and doing the required re-plumbing to put the rectangular block in service that the HD truck use. Looks like Wild one has pretty much accomplished that by using half of the Thermal dingus to secure the o-ring tubes into the Tranny by plugging the radiator coolant openings. Great work guys, I am sponging it all in for when my warranty has gone by-by.

This can all be done basically for free,lol. 5/16" X 18 NC set screws are a virtual perfect fit for the fluid bypass holes after you tap them,i didn't even drill the holes,just ran a tap through them.If you pull the pipe plug out and the plug for the thermostat,it's wide open internally to blow all the shavings out from running a tap through the bypass holes,then JB Weld the set screws in place,loop the coolant hoses together either on top of the tranny,or at the engine,and just re-install the fluid part of the thermal unit,and toss the bulky heat exchanger into storage,or into your recycle bin if you don't want it laying around,peeing you off,lol. The hardest part of the job is getting at the heater hoses on top of the thermal unit,i ended up unbolting the tranny crossmember and driveshaft then used a floor jack under the transfer case to drop the tranny down slightly to have enough room to get at the hoses.You might be able to do it with-out dropping the tranny,but for all it takes to pull the 4 bolts out of the crossmember ,i found that to be the easiest way to get at the hoses.To remove the tranny fluid lines,you need to pop the small white plastic caps up and off the circlips,then use a small pick to pull the circlips holding the cooler lines into the thermal unit,and the cooler lines just pop up and out of the thermal unit.Hang onto the circlips,as they might want to fly off on a tangent and are small enough to be hard to find if they do,ask me how i know,lol. I did it over 2 evenings,just to let the JB Weld some time to set up,but if you used pipe dope/sealant on the set screws you could do it easy in a couple hours. Once the unit is dis-assembled i just used my old syphon wash gun and some gas to wash it up,then blew it out really good to get rid of any traces of gas.A varsol tank would do the same thing,but i don't have one,so it was gas and the good ole syphon wash gun hooked to my compressor,yea i know the redneck way to clean things,but that's me,lol

 

[crazykid1994]

I deleted the heater completely.Tapped the bypass holes and JB Welded in some 3/16's plugs into the bypass holes,sure cleans up the side of the tranny.Also looped the coolant hoses on top of the transmission together . Once you disassemble the unit,it's pretty easy to see how they route the coolant through the heater and how the fluid bypass is routed. Only took a couple evenings to clean it up,lol

View attachment 234878

Bypass holes plugged

View attachment 234879

View attachment 234880

These are the updated transfer tubes,with-out the O-ring on them. I'm not sure when FCA updated these tubes,but i think anything newer then 16 probably has these tubes instead of the earlier leak prone O-ring versions

View attachment 234881

What plugs did you use? I’ll be deleting the heater block this week. Picked up a leak between the plate and the main body of the thermal unit where the o rings seat... not very happy. I’ll be going to my dealer and see if I can get some unicorn oil for the transmission. Pull the thermal unit off and tap the holes same as you did so I can get rid of the coolant lines and the leak. I can’t seem to find 3/16 plugs local

 

[crackerjack1957]

What plugs did you use? I’ll be deleting the heater block this week. Picked up a leak between the plate and the main body of the thermal unit where the o rings seat... not very happy. I’ll be going to my dealer and see if I can get some unicorn oil for the transmission. Pull the thermal unit off and tap the holes same as you did so I can get rid of the coolant lines and the leak. I can’t seem to find 3/16 plugs local

Probably a typo.....maybe 5/16-18.....I'm sure Rick will let you know

 

[Wild one]

What plugs did you use? I’ll be deleting the heater block this week. Picked up a leak between the plate and the main body of the thermal unit where the o rings seat... not very happy. I’ll be going to my dealer and see if I can get some unicorn oil for the transmission. Pull the thermal unit off and tap the holes same as you did so I can get rid of the coolant lines and the leak. I can’t seem to find 3/16 plugs local

I used 5/16" NC set screws for the plugs. They're more commonly used to lock pulleys etc. onto shafts or keyways.
I have a kit very similiar to this kit,mine does have a better selection of set screws then this kit has,but i also payed noticably more for it years ago.
Amazon.com: Neiko 50484A Internal Hex Allen Set Screw Assortment | Full Steel Construction | Includes Coarse & Fine Thread Screws | 200 Piece, 5/32" x 3/16"/1/4" x 3/8": Industrial & Scientific

 

[crazykid1994]

I used 3/16" NC set screws for the plugs. They're more commonly used to lock pulleys etc. onto shafts or keyways.
I have a kit very similiar to this kit.You could probably use a 10-24 set screw to,as they're very close to a 3/16" set screw,you'd just need a 10-24 tap instead of a 3/16 tap.
Amazon.com: Neiko 50484A Internal Hex Allen Set Screw Assortment | Full Steel Construction | Includes Coarse & Fine Thread Screws | 200 Piece, 5/32" x 3/16"/1/4" x 3/8": Industrial & Scientific

I have both a 10-24 and a 1/4-20 tap in my set and I can do a stainless hex bolt in either size. I’ll pull the unit and check fitment on the 10-24 and see how it fits. I’ll probably use atf gasket maker on the threads.

 

[Wild one]

I have both a 10-24 and a 1/4-20 tap in my set and I can do a stainless hex bolt in either size. I’ll pull the unit and check fitment on the 10-24 and see how it fits. I’ll probably use atf gasket maker on the threads.

The pipe plug in the other end of the router plate is in there tight,i removed it for cleaning purposes,but you could probably get away with out pulling it,if it gives you static,as once the cooler lines are removed the internal passages are fairly open to blow out any shavings from the tap

 

[Wild one]

Deleted

 

[crazykid1994]

Khristopher if you have a 10-24th tap,i'd just grab a couple small 10-24 X 1/2" long machine screws and use them.A 10-24 machine screw is pretty easy to find at any hardware store or automotive parts store.There's probably enough meat in the housing to maybe go to a 3/4" long machine screw if you can't find a 1/2" long machine screw.

Yea I’ve got some already. Plus I’ve got a few hardware stores around me. I’ll let you know how it goes later this week. I’ve been working like crazy lately. I’m going to try Wednesday to do the work

 

[crackerjack1957]

We have a 3/16-24 in the USA.......LoL

https://www.lincolnmachine.com/tap_drill_chart.html

 

[Wild one]

I seriously *****'d,lol. I've been saying 3/16's,but they're actually 5/16's X18 NC. Sorry about that Khristopher,and i owe CJ57 a thank-you for making me go check the size. Sorry guys my mistake.
Rick