Transmission Towing Temperature - V8
05-22-2018, 02:26 PM
#1
Transmission Towing Temperature - V8
I know there are several threads on this, but mostly speculation on if/when tranny damage may occur. I have done a lot of research on this and thought I'd share here and get some feedback on my experience.
I have a 2016 SCREW, 6.5, V8, 3.55 dif. I tow a 27-foot travel trailer that when fully loaded is about 6000lb. Add to that two adults and three kids in the truck. I have done all the weight calculations and am well within all payload and axle ratings. I even go as far as weighing my tongue weight each time I hook up with a Sherline scale. Engine power is not a problem. What is an issue (I think) is the transmission temperatures I hit when going up long hills/mountains. I live in BC so if you are not going up, you are going down.
I took the trailer out of storage last weekend and drove it home. Weight well under 6000lb, around 5300lb - 5500lb and just me in the truck. Even with that, going up a long hill at the speed limit of 70km/h (about 45mph) the tranny hit 113C (235F). I did have to slow down for two large corners and accelerate out of them back up to 70km/h. The truck used 2nd and 3rd gear. The temp needle never moved from its normal position, but I did see the needle move last summer. One theory I have is that the torque converter is not getting a chance to lock. On large inclines, the truck needs to be around 3500 - 3800 rpm to get the torque it needs. To do that at 70km/h that means 2/3rd gear. To quote @smokeywren 'a volcano worth of heat' is being produced that the cooler can't keep up with. I have tried using manual mode but makes little difference, and yes I am in tow/haul.
I have asked at my dealership and a mechanic there feels short periods above 220 are ok and should have no effect on the tranny fluid and tranny internals. If that is the case, I can live with it. However, if I am slowly roasting my tranny and or tranny fluid by towing what I think the truck should handle, this could end badly. All events when I have reached these temperatures are under 10 minutes in length.
Does anyone have a similar experience? Open to any thoughts on this.
Thanks.
I have a 2016 SCREW, 6.5, V8, 3.55 dif. I tow a 27-foot travel trailer that when fully loaded is about 6000lb. Add to that two adults and three kids in the truck. I have done all the weight calculations and am well within all payload and axle ratings. I even go as far as weighing my tongue weight each time I hook up with a Sherline scale. Engine power is not a problem. What is an issue (I think) is the transmission temperatures I hit when going up long hills/mountains. I live in BC so if you are not going up, you are going down.
I took the trailer out of storage last weekend and drove it home. Weight well under 6000lb, around 5300lb - 5500lb and just me in the truck. Even with that, going up a long hill at the speed limit of 70km/h (about 45mph) the tranny hit 113C (235F). I did have to slow down for two large corners and accelerate out of them back up to 70km/h. The truck used 2nd and 3rd gear. The temp needle never moved from its normal position, but I did see the needle move last summer. One theory I have is that the torque converter is not getting a chance to lock. On large inclines, the truck needs to be around 3500 - 3800 rpm to get the torque it needs. To do that at 70km/h that means 2/3rd gear. To quote @smokeywren 'a volcano worth of heat' is being produced that the cooler can't keep up with. I have tried using manual mode but makes little difference, and yes I am in tow/haul.
I have asked at my dealership and a mechanic there feels short periods above 220 are ok and should have no effect on the tranny fluid and tranny internals. If that is the case, I can live with it. However, if I am slowly roasting my tranny and or tranny fluid by towing what I think the truck should handle, this could end badly. All events when I have reached these temperatures are under 10 minutes in length.
Does anyone have a similar experience? Open to any thoughts on this.
Thanks.
05-22-2018, 06:54 PM
#2
Senior Member
Not to hot - only 40 degrees over T stat. Do you have an external trans cooler/is it clean and not blocked?
I don't have an numerical display to compare on my trucks but if your really crawling up a steep incline its probably normal at lower speeds depending on ext temp and air flow. I agree if the TQ is not locked up the temps will rise quickly. Hope someone can give you a better answer or advise on what's considered normal. Maybe staying in 2nd would lower that temp a little.
I don't have an numerical display to compare on my trucks but if your really crawling up a steep incline its probably normal at lower speeds depending on ext temp and air flow. I agree if the TQ is not locked up the temps will rise quickly. Hope someone can give you a better answer or advise on what's considered normal. Maybe staying in 2nd would lower that temp a little.
05-22-2018, 07:04 PM
#3
Senior Member
Not to hot - only 40 degrees over T stat. Do you have an external trans cooler/is it clean and not blocked?
I don't have an numerical display to compare on my trucks but if your really crawling up a steep incline its probably normal at lower speeds depending on ext temp and air flow. I agree if the TQ is not locked up the temps will rise quickly. Hope someone can give you a better answer or advise on what's considered normal. Maybe staying in 2nd would lower that temp a little.
Good info here and watch the whole video
I don't have an numerical display to compare on my trucks but if your really crawling up a steep incline its probably normal at lower speeds depending on ext temp and air flow. I agree if the TQ is not locked up the temps will rise quickly. Hope someone can give you a better answer or advise on what's considered normal. Maybe staying in 2nd would lower that temp a little.
Good info here and watch the whole video
05-23-2018, 12:28 PM
#4
Not to hot - only 40 degrees over T stat. Do you have an external trans cooler/is it clean and not blocked?
I don't have an numerical display to compare on my trucks but if your really crawling up a steep incline its probably normal at lower speeds depending on ext temp and air flow. I agree if the TQ is not locked up the temps will rise quickly. Hope someone can give you a better answer or advise on what's considered normal. Maybe staying in 2nd would lower that temp a little.
Good info here and watch the whole video click
I don't have an numerical display to compare on my trucks but if your really crawling up a steep incline its probably normal at lower speeds depending on ext temp and air flow. I agree if the TQ is not locked up the temps will rise quickly. Hope someone can give you a better answer or advise on what's considered normal. Maybe staying in 2nd would lower that temp a little.
Good info here and watch the whole video click
Yes, I have the towing package that has the tranny cooler radiator in front of the regular radiator. Best I can tell it is clean. I have looked through the shutters with a flashlight when starting the truck and the shutters cycle open/closed.
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Bluewoo (05-23-2018)
05-23-2018, 12:56 PM
#5
I have a 2018 XLT 5.0 HDPP screw and I tow a 32ft TT 7.6k gross weight, 2 adults, 3 kids, with 200# of gear in the bed. Went through VT mountains last weekend at 100-110 km/h and the tranny never went above 98C. I have the 10spd, it was shifting between 5 to 9. Rpm never above 4k uphill.
05-23-2018, 07:07 PM
#6
Senior Member
235f is fine for the times you describe. Well within the "normal" range of the transmission. I've hit the same temps at slow speed coming out of Pemberton on Hwy 99. the truck will throttle back at 255f as per the OBD manual. It will run at 195-210f due to the thermostat in the 6r80.