8hp70 heater bypass

[hawsk99gt]

I don't think your truck has the 3 way valve,as it was only used on the earlier 8 speeds,and i think they quit using it on the 16's. Do you still have the shutters in place? As Star said it might be worth pulling the grill and hosing out the A/C condensor and rad with a spray on rad cleaner and a trip through your local coin-op carwash .

I still have my shutters in place. And I will do an investigation and pull the grill this weekend. If this was something consistent I would think that it would be some kind of blockage. But that it happens from time to time is weird.

 

[hawsk99gt]

I was doing some online searching again and I came across another forum where they were having the same complaint about overheating transmissions. The very last post which was from 2021 said he found a fix. This is his quote and I was wondering if this could be a possible fix for me:

"I just had the same problem with my supposedly transmission overheating all the water from your radiator actually flows into the side of the transmission to help heat it up I guess in the winter so the problem with mine was my electric AC radiator cooling fan had a short in it if you hit it with a screwdriver when the truck was off it would start running so if that’s what caused my AC to run hot,truck to get hot at idle and the transmission after about an hour driving on the highway but feel like someone slammed in the back of you and would go into dummy mode it was all because of the electric radiator fan $175 part."

 

[Wild one]

I was doing some online searching again and I came across another forum where they were having the same complaint about overheating transmissions. The very last post which was from 2021 said he found a fix. This is his quote and I was wondering if this could be a possible fix for me:

"I just had the same problem with my supposedly transmission overheating all the water from your radiator actually flows into the side of the transmission to help heat it up I guess in the winter so the problem with mine was my electric AC radiator cooling fan had a short in it if you hit it with a screwdriver when the truck was off it would start running so if that’s what caused my AC to run hot,truck to get hot at idle and the transmission after about an hour driving on the highway but feel like someone slammed in the back of you and would go into dummy mode it was all because of the electric radiator fan $175 part."

Take the truck for a drive and get it warmed up,then park it ,leave it running , open the hood , then lean back in the door and turn the A/C on high,you should be able to easily hear the electric fan cycle onto high as soon as you turn the A/C on high.If you hear nothing really change,then your A/C fan might not be working .

 

[CanuckRam1313]

Ok, all is good after the install of @caulk04's THB(transmission heater bypass/thermostat delete)valve. Trans temp(s) are ~ 45° cooler with the average outside temperature 80°.

The before the install the transmission temps was ~ 179°-185°. After the install the temp(s) are ~ 129°-150°ish while driving highway and idling at stop lights, etc. That's much better.

However, the coolent and oil temps were up about 10° from where they normally were, coolent hovered around ~ 199°-203° and oil was ~ the same.

I resolved that by doing an partial AGS delete(removing all the shutters except for the top and bottom rows)and now these temps are back down to where they normally were.

All is good.

Interesting your coolant temp went up after the @caulk04 bypass install.

Mine went down both on the mechanical gauge on the dash and numerically down looking on the EVIC.

I have all my shutters still in place and the stock t-stat, and have done some heavy driving in very hot Ontario weather this season and my transmission still stays about 150 according to the EVIC. My oil hasn't gone over 220, and my coolant hasn't gone over 215.

I am however considering installing a 190 t-stat just to maintain some cooler temps. Regardless, my truck is quite happy and runs flawlessly at any time.

I couldn't be happier with my HEMI Ram

 

[hawsk99gt]

Interesting your coolant temp went up after the @caulk04 bypass install.

Mine went down both on the mechanical gauge on the dash and numerically down looking on the EVIC.

I have all my shutters still in place and the stock t-stat, and have done some heavy driving in very hot Ontario weather this season and my transmission still stays about 150 according to the EVIC. My oil hasn't gone over 220, and my coolant hasn't gone over 215.

I am however considering installing a 190 t-stat just to maintain some cooler temps. Regardless, my truck is quite happy and runs flawlessly at any time.

I couldn't be happier with my HEMI Ram

Other than my heat issue, I love my truck. I do feel that caulk04 by pass has worked (have had it installed for almost a couple of years now) because I have not experienced the 285* temps any more. Like I said it is not all the time. I have driven for 2 hours on hot days and the temps have stayed at 160*. But some times after stopping at a destination, I then start my return trip it will just start climbing, especially on the highway. I'll pull over and let it cool down for 15minutes it will go back to normal temps continuing on the highway at 75 to 80 mph. No rhyme or reason.

 

[JHoward]

Interesting your coolant temp went up after the @caulk04 bypass install.

Mine went down both on the mechanical gauge on the dash and numerically down looking on the EVIC.

I have all my shutters still in place and the stock t-stat, and have done some heavy driving in very hot Ontario weather this season and my transmission still stays about 150 according to the EVIC. My oil hasn't gone over 220, and my coolant hasn't gone over 215.

I am however considering installing a 190 t-stat just to maintain some cooler temps. Regardless, my truck is quite happy and runs flawlessly at any time.

I couldn't be happier with my HEMI Ram

I've thought about installing the 180° t-stat, but the partial AGS delete helped to bring the coolent temp back down. I may still try that out ...

Yep, the transmission t-stat delete along with the partial AGS delete is an much better improvement on temps. All is good.

 

[hawsk99gt]

Take the truck for a drive and get it warmed up,then park it ,leave it running , open the hood , then lean back in the door and turn the A/C on high,you should be able to easily hear the electric fan cycle onto high as soon as you turn the A/C on high.If you hear nothing really change,then your A/C fan might not be working .

Well did this test and the electric fan kicked on, like it should. Guess I can scratch that off the list. Still need to pull a part the front grill and see if there is anything clogging up the area. Ran out of time this weekend.

 

[hawsk99gt]

OK so I started taking the shroud off preparing to do my investigation with the radiator to see if anything is plugging it up. I noticed a plug that is not connected to anything and was wonder if anyone knew what this goes too.

 

[hawsk99gt]

I've thought about installing the 180° t-stat, but the partial AGS delete helped to bring the coolent temp back down. I may still try that out ...

Yep, the transmission t-stat delete along with the partial AGS delete is an much better improvement on temps. All is good.

after deleting your transmission T-STAT, are you still able to monitor your transmission temps?

 

[Wild one]

after deleting your transmission T-STAT, are you still able to monitor your transmission temps?

Yes you can still monitor transmission temps with or with out the transmission thermostat.There is no electrical connections to the TMU which is where the thermostat is located

 

[16Ram4x4]

Hawksk99gt if that connection is a single brown wire it's for the remote start hood switch

 

[hawsk99gt]

Hawksk99gt if that connection is a single brown wire it's for the remote start hood switch

Oh Ok, thanks. That's probably it. It was kind of random, just sitting there. I'll check that when I'm working on it again tonight.

 

[BlownGP]

Still loving Jessie heater bypass mod.

With the 180 T-stat, shutters removed and bypass mod my truck stays cool even when it 100* out. Can't beat it

 

[hawsk99gt]

I have gone and removed the AGS, all but the top and bottom. I did a short run around town for 30 min. But that's not really a test. The highest my trans temp got was 154* which has always been normal to me. The oil Temp got to 215* and coolant was around 205* off and on. I won't really know if this MOD is helping till I do a long distance run on the hi-way. It is about 88* here today while I was driving. While doing the AGS removal, I did not see any blockage around the radiator and AC cooler, other than a few little bugs and dust. Actually pretty clean for a 2016. I did notice and corrected on the left side of the AGS the flexible shroud/liner was folded over & slammed against 2 metal lines going towards the RAD area. I straightened it out as best as I could to resemble the right side. That was the only thing that looked wrong. I'll report back my temps once I go on a long trip.
Oh I did talk to another dealers service agent that was further away to feel them out with possibly seeing if they had seen this before. She hadn't heard of it, but she said that she would talk to her trans/engine mechanic about this and get back to me today but as usual no call back. Oh well, I will see how this latest MOD helps. My next project will be to replace my TSTAT for the RAD to help with cooler temps, not to mention it is my original TSTAT that came with the truck.

 

[BlownGP]

I have gone and removed the AGS, all but the top and bottom. I did a short run around town for 30 min. But that's not really a test. The highest my trans temp got was 154* which has always been normal to me. The oil Temp got to 215* and coolant was around 205* off and on. I won't really know if this MOD is helping till I do a long distance run on the hi-way. It is about 88* here today while I was driving. While doing the AGS removal, I did not see any blockage around the radiator and AC cooler, other than a few little bugs and dust. Actually pretty clean for a 2016. I did notice and corrected on the left side of the AGS the flexible shroud/liner was folded over & slammed against 2 metal lines going towards the RAD area. I straightened it out as best as I could to resemble the right side. That was the only thing that looked wrong. I'll report back my temps once I go on a long trip.
Oh I did talk to another dealers service agent that was further away to feel them out with possibly seeing if they had seen this before. She hadn't heard of it, but she said that she would talk to her trans/engine mechanic about this and get back to me today but as usual no call back. Oh well, I will see how this latest MOD helps. My next project will be to replace my TSTAT for the RAD to help with cooler temps, not to mention it is my original TSTAT that came with the truck.

Don't know if the AGS will fix your problem but it should help. It's a stupid feature, my 09 Ram didn't have that crap and gas mileage was not any worse before I pulled the AGS on my 2018.

 

[JHoward]

I have gone and removed the AGS, all but the top and bottom. I did a short run around town for 30 min. But that's not really a test. The highest my trans temp got was 154* which has always been normal to me. The oil Temp got to 215* and coolant was around 205* off and on. I won't really know if this MOD is helping till I do a long distance run on the hi-way. It is about 88* here today while I was driving. While doing the AGS removal, I did not see any blockage around the radiator and AC cooler, other than a few little bugs and dust. Actually pretty clean for a 2016. I did notice and corrected on the left side of the AGS the flexible shroud/liner was folded over & slammed against 2 metal lines going towards the RAD area. I straightened it out as best as I could to resemble the right side. That was the only thing that looked wrong. I'll report back my temps once I go on a long trip.
Oh I did talk to another dealers service agent that was further away to feel them out with possibly seeing if they had seen this before. She hadn't heard of it, but she said that she would talk to her trans/engine mechanic about this and get back to me today but as usual no call back. Oh well, I will see how this latest MOD helps. My next project will be to replace my TSTAT for the RAD to help with cooler temps, not to mention it is my original TSTAT that came with the truck.

Report back, I'm interested to know.

 

[Daniel Ortiz]

@hawsk99gt if I were you I'd keep pressing that service dealer to talk to her transmission friend (or really any transmission expert that is knowledgeable on Ram's ZF 8HP70 setup). If possible, ask if she wouldn't mind if you could contact them directly (of vice versa). I think at your level of double-plus-ungood thermostat-deleted transmission limbo, if I were you, I'd be trying to learn as MUCH about that transmission's setup as I could. Also, I hope you've kept track of as many factors that are occurring when you have "the problem," and also when you DON'T have the problem, because it sounds like it's down to detective work now.

I wish you the absolute best luck. Mine has been happy as a clam since I installed the thermostat delete plug, so my problem was obviously the thermostat sticking. But yours... <sigh>. It's a tough cookie.

 

[hawsk99gt]

@hawsk99gt if I were you I'd keep pressing that service dealer to talk to her transmission friend (or really any transmission expert that is knowledgeable on Ram's ZF 8HP70 setup). If possible, ask if she wouldn't mind if you could contact them directly (of vice versa). I think at your level of double-plus-ungood thermostat-deleted transmission limbo, if I were you, I'd be trying to learn as MUCH about that transmission's setup as I could. Also, I hope you've kept track of as many factors that are occurring when you have "the problem," and also when you DON'T have the problem, because it sounds like it's down to detective work now.

I wish you the absolute best luck. Mine has been happy as a clam since I installed the thermostat delete plug, so my problem was obviously the thermostat sticking. But yours... <sigh>. It's a tough cookie.

Yes it is. And thanks. I will try to keep pressing on.

 

[TotallyHucked]

I can honestly say after having the AGS delete done for over a month now, my truck consistently runs ~10* cooler, coolant temp wise. Trans is about the same, I haven’t installed my bypass yet

 

[hawsk99gt]

I can honestly say after having the AGS delete done for over a month now, my truck consistently runs ~10* cooler, coolant temp wise. Trans is about the same, I haven’t installed my bypass yet

Yeah, I would say it is running cooler so far, but as far as testing the trans, I haven't done a long highway test yet