Hemi Towing coolant and transmission Temperatures?

[socalluke]

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?

[PWJouster]

since you modified your trans, you may as well throw additional cooling capacity in there. Another radiator would do alot for you.

[Colibri]

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

[socalluke]

Thanks @colibri. Exactly what I was looking for

[ghaugo]

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.

[ghaugo]

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.

[EasyDoesIt]

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).

[jeep_boy02]

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.

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