Towing Hot?

[07LBZWash]

Hello,

Been lurking for a while now and searching and I can't seem to find a consistent answer on just how hot is too hot and if I may need to do a flush and replace or not. Here's the situation.

Towing up Vantage pass here in Washington, very long and steady, temp was about 83* out. Towing a 7k lbs trailer in tow/haul mode. Doing 65 mph at about 2600 RPM's. Tranny temp was 220-230 and the engine kept getting up to 225-230 (halfway between 210 and 260). The engine fan came on 3 times and did cool the coolant temps down to about 210 but the tranny stayed where it was till about 1 or 2 miles on the down slope then camp back down fairly quickly. I called the dealership to see about a flush as I thought this was too hot for these trucks and that load, but they said that's normal. Not really sure what to think here, some guys say yeah that's fine and others are running way cooler.

Ran into a guy at a gas station right after, had the same exact truck just an 06, still the LBZ and he just pulled the same pass as me and said his tranny temp barely got to the first mark above 100 and the engine fan only came one once. He also said he was running all synthetic throughout the engine.

Also do you guys believe in the additives for the engine like Water Wetter or Tranny Wetter or even the additive for the gas? Any help is appreciated and again I'm sorry this has been asked so much just trying to see if my scenario sounds right or not.

The dealership I bought it from gave me a 3 month warranty and certified it so if there is a problem I want to find out now so I can make them fix it.

Jim

 

[malibu795]

according to GM the engine isnt in danger until ECT reaches 250*F ~251* ecm limps the truck.

the coolers all 4(tranny, a/c, CAC, rad) could be clogged with dirt/bugs to one degree or another.

i run an 06 LBZ long grades of 6% or steeper i will see above 220* ECT rolling 23,000lb+. anything less is is barely 210* i have also up graded the fan clutch to a hayden 2886 fan clutch. which come on alot sooner then stock.

drove I90 in a big truck through washington quite a bit.. nice veiw out there...

 

[gmduramax]

2600rpm is too high. Pulling grades I try to keep it around 2200rpm but that's just my opinion.
I towed 10,000lbs up the grapevine at 75mph and my coolant temp stayed at 210 and outside temp was 85*

 

[malibu795]

2600rpm is too high. Pulling grades I try to keep it around 2200rpm but that's just my opinion.
I towed 10,000lbs up the grapevine at 75mph and my coolant temp stayed at 210 and outside temp was 85*

too high? i've been doing it for just under 120,000 miles, i cruise at 2400-2500(4th).. with an avg gross weight of 24,000lbs
i will run a 6% at 2900 (3rd, which about 58-59mph) it uses less throttle vs running up in 4th at full throttle then just to have it down shift out of OD

 

[gmduramax]

too high? i've been doing it for just under 120,000 miles, i cruise at 2400-2500(4th).. with an avg gross weight of 24,000lbs
i will run a 6% at 2900 (3rd, which about 58-59mph) it uses less throttle vs running up in 4th at full throttle then just to have it down shift out of OD

I also tow with 500hp I'm sure that makes it different

 

[malibu795]

I also tow with 500hp I'm sure that makes it different

i know i could run a 5% at 75 grossing ~17,000(10,000lb trailer) but i'd be turning 2800 just to do it.. some times i dislike have short legged truck

but since the OP didnt state his power level im taking an educated gues that is stock or close to stock power.. which is still more then me :rofl:

 

[fast03]

I have found that 2300-2500 seems to be best for extended hills.

 

[crbonline]

I pull a trailer that weighs 13.5k dry and 18.5k loaded (trailer weight only) all over nor cal including the i80 donner pass and some other gnarly climbs. I've been dealing with heat issues since day one and have put a LOT of time into researching and remedying. My two cents...you don't want your coolant to get over 240 because it starts to defuel/limp...tranny should never get over 240 or else you gotta change fluid...and that is with Transynd in it.

I just added (in addition to my Mike L tranny cooler) the BD remote extruded tranny cooler with fan and in the most extreme conditions i've never peaked 191. Before the BD it would occasionally hit 230-240 in same conditions.

Re: RPMS...I look for 2400-2700 rpm...this ensures the turbo is doing its job and blowing as much hot air as possible. Any lower your turbo is not doing all it can. I also find myself at 2900 a lot because I refuse to let off the throttle...with all the cooling mods i have it works out because I usually peak the grade before temps get out of control.

If you tow a lot in hot temps in elevation pulling heavy loads with high wind drag, you gotta get a secondary radiator. I have the TxC Rad Mod v2 with fan which is no longer available but the Engineer837 DIY setup is available and is comprable the TxC version. Without a secondary radiator, I would find myself on the road every trip waiting for the truck to cool down.

 

[07LBZWash]

Thanks for the input guys. Talked to a friend of mine that owns a shop and he was saying that it's not bad but it's not great either. Taking it up and he's gonna redo all the filters on the Allison and flush and fill for me. And test to make sure the right ratio of coolant is in there, that should alleviate my concerns.

 

[THEFERMANATOR]

Sounds like it's working fine to me. Your trans temps are a tad high, but not bad. 225-235 when towing is right where the fan comes on at running 65-70, so your not going to get it to run much cooler unless you modify your fan clutch. Your stats begin to open at 180(rear stat), and they go fully open as per my manual at 212. So until 212 degrees you aren't even getting full flow through your radiator. If your fan clutch is original it is a good idea to change it as they should be done every 5 years on a truck that tows a lot, and for a daily driver they should be done every 7-10 years. Pulling the radiator out and cleaning out the cooling stack is also a good idea as you would be shocked at how many bugs and crap can build up in them in just a short time.