Hemi Towing coolant and transmission Temperatures?

Post Reply
socalluke
Posts: 25
Joined: Mon Nov 24, 2014 8:43 pm
Model Year: 2012

Hemi Towing coolant and transmission Temperatures?

Post by socalluke » Wed Jun 17, 2020 11:48 am

After smoking my overdrive clutches in the 2012 transmission a year ago, for a number of reasons. Pulling a 7-9k lb toyhauler with WDH.

Currently 1) Now have tuner, with tires changed to correct size of 35inch tires. 2) Shift kit in trans with firmer shifts and hunts less and 3) will limit to 4th and down or 3rd and down based on grade and lastly 4) drive up mountain grades based on engine rpm, Not trying to maintain a certain speed.

Just got back from a 900 mile tow. LA - Chandler - Flagstaff - LA. (4th gear, 2800 rpm, and 62 mph. Kept the coolant and trans temps the coolest.)

But on the 2nd climb in a row, (meaning the neither trans or coolant had a chance to cool back down) the trans temp got up to 230)
Coolant would get up around 221 a fair amount throughout the trip. Once when the coolant hit 225, I turned off the A/C and the coolant temp dropped almost 10 degrees super fast.

With CA and AZ heat over 100 degrees and mountain grades pushing the limits, At what Temperature would you pull over and let it cool off?
1. Coolant Temp?
2. Trans Temp?
3. And other than as cool as possible, at what temperatures would you consider it is okay to run at?

User avatar
PWJouster
250_Posts
250_Posts
Posts: 463
Joined: Wed Dec 27, 2017 8:44 am
Model Year: 2018

Re: Hemi Towing coolant and transmission Temperatures?

Post by PWJouster » Wed Jun 17, 2020 11:55 am

since you modified your trans, you may as well throw additional cooling capacity in there. Another radiator would do alot for you.
2018 Powerwagon-6.4 Hemi
Nanny kill switch and Locker Bypasses
Thuren Tuned King 3.0 & 2.5 Pintop Stage 3/2
17 Method NV-Toyo RT 37
Evo On-Demand Air Swaybar Disconnect
S&B Intake-Mufflex-Magnaflow/resonator delete
SPOD Bantam
On-Board air ARB CKMTA12
Baja design and Rigid Industries
Purple Cranium Spider dif guards
Pedal Commander

Colibri
1000_Posts
1000_Posts
Posts: 1713
Joined: Mon Jun 08, 2015 5:44 pm
Model Year: 2009

Re: Hemi Towing coolant and transmission Temperatures?

Post by Colibri » Mon Jul 27, 2020 12:53 am

Coolant temp is okay from around 195/205 up to around 230 or sounder heavy load, that’s pretty normal. Also consider that your oil temperatures can be 10-20 degrees higher than coolant especially under load.

ATF+4 is pretty decent stuff, it’ll handle high temps better than some fluids, but ideally I wouldn’t let it hit 230 with any regularity. 170-190 is ideal

Check your trans fluid condition and consider a drain/ refill.

Buna and nitrile start to shit the bed over 250, those materials account for a fair number of seals and o rings in a drivetrain. Something to keep in mind
Central Texas and Houston area
2009 5.7 auto quadcab
Carli 3” coils deaver leafs 3” kings with 4 tube bypass rear and fr/rr hydro bumps
Howe steering pump and gear with hydraulic ram assist
Custom tube bumpers and white knuckle sliders
Creative fab trussed axle. rem polished and cryoed 5.13 gears with arb lockers fr/rr
Sharadon stage 2 545rfe with 3000 stall edge converter
Lots of other stuff lol

socalluke
Posts: 25
Joined: Mon Nov 24, 2014 8:43 pm
Model Year: 2012

Re: Hemi Towing coolant and transmission Temperatures?

Post by socalluke » Sat Aug 01, 2020 12:33 pm

Thanks @colibri. Exactly what I was looking for

User avatar
ghaugo
50_Posts
50_Posts
Posts: 141
Joined: Wed Sep 20, 2017 12:04 am
Model Year: 2012
Location: Loveland, CO

Re: Hemi Towing coolant and transmission Temperatures?

Post by ghaugo » Mon Mar 22, 2021 6:26 pm

I just towed my 32' camper (7,000lbs approx) from CO to AZ for a vacation. 934 miles each way. I pulled some steep grades up and down from Holbrook to Mesa and the truck did very well. I also fought a ton of headwind on the way out. My coolant got to about 219 when it was 70 and running the AC. The trans temps never got above 191. Oil temps got to 250 doing extended runs at over 4,000 rpms. I run all Amsoil fluids and they really seem to do the trick on my rig. The truck did a great job.
2012 Power Wagon
Frame-welded Aluminess Rock Sliders(welded to frame), Kenda Klever RT (35/12.50R17), ARE Z-Series Topper, FilterMag GP101 (front and rear diffs), DeeZee Tailgate Assist, Skanda Kryptec Typhoon seat covers, Husky X-act Contour Mats, Purple Cranium Diff Covers Front and Rear, Dodge Offroad Steering Brace, K&N air filter, Thuren Track Bar, Thuren Short Arms, Thuren Overland Shocks, Airlifter Ultimate 5000 airbags, Daystar Cradles, High Country Customs Bumper, Dynatrac ball joints, All AMSOIL fluids from Code4Synthetics.com

User avatar
ghaugo
50_Posts
50_Posts
Posts: 141
Joined: Wed Sep 20, 2017 12:04 am
Model Year: 2012
Location: Loveland, CO

Re: Hemi Towing coolant and transmission Temperatures?

Post by ghaugo » Mon Mar 22, 2021 6:26 pm

I just towed my 32' camper (7,000lbs approx) from CO to AZ for a vacation. 934 miles each way. I pulled some steep grades up and down from Holbrook to Mesa and the truck did very well. I also fought a ton of headwind on the way out. My coolant got to about 219 when it was 70 and running the AC. The trans temps never got above 191. Oil temps got to 250 doing extended runs at over 4,000 rpms. I run all Amsoil fluids and they really seem to do the trick on my rig. The truck did a great job.
2012 Power Wagon
Frame-welded Aluminess Rock Sliders(welded to frame), Kenda Klever RT (35/12.50R17), ARE Z-Series Topper, FilterMag GP101 (front and rear diffs), DeeZee Tailgate Assist, Skanda Kryptec Typhoon seat covers, Husky X-act Contour Mats, Purple Cranium Diff Covers Front and Rear, Dodge Offroad Steering Brace, K&N air filter, Thuren Track Bar, Thuren Short Arms, Thuren Overland Shocks, Airlifter Ultimate 5000 airbags, Daystar Cradles, High Country Customs Bumper, Dynatrac ball joints, All AMSOIL fluids from Code4Synthetics.com

EasyDoesIt
250_Posts
250_Posts
Posts: 311
Joined: Fri Jan 05, 2018 11:32 am
Model Year: 2018
Location: Las Vegas, NV

Re: Hemi Towing coolant and transmission Temperatures?

Post by EasyDoesIt » Thu Jul 01, 2021 9:58 am

2018, all Amsoil fluids, 37s, 5.13 gears

Towing my 8500lb'ish trailer up 13% grades for several miles (3,000 ft above sea level to almost 11,000 ft above sea level).

Outside temps started above 105 but we're much cooler at the top.

1st/2nd gear most the way...wrapped out 1st.

By far the hardest I've ever towed and definitely made me consider a Cummins (never going to happen but I thought about it).
PXL_20210618_205224191.jpg
Live: Las Vegas NV, Drive: 2018 PW & 2014 LR4

User avatar
jeep_boy02
1000_Posts
1000_Posts
Posts: 1015
Joined: Sat Feb 16, 2013 1:21 pm

Re: Hemi Towing coolant and transmission Temperatures?

Post by jeep_boy02 » Sat Jul 03, 2021 9:35 pm

So what's the temp gauges parameters? Looks dead center but I'd think at nearing 230 it'd be 3/4 to "H"...

How's the 5.13s with 37s? I was considering bumping up to 37s but sticking with the 4.56s. But I'm contemplating what drops in towing I'd be facing. Most towing is around 7000 lbs.

Sent from my SM-A015A using Tapatalk

2010 black pearl(PXR) on 35s, bypass harness, gooseneck, CAI, 3" magnaflow catback, bulldog hemi GT.... more to come soon

Post Reply