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Discussion Starter · #1 ·
Not sure if this should go under towing or trans,but here's my deal.I went camping this weekend and when towing my bumper pull TT I had the trans on M5 and T/H. Made a pit stop before the turnpike and put truck in M5 again but forgot to hit T/H.I made 90% of the trip without noticing since it was towing pretty good even on the slight hills on the NE Extension heading in PA,it did wanna wind out gears kinda long on some but didn't feel like truck was struggling to pull trailer.My trailer is prob 9k loaded for this trip.Dry weight is 8400lbs.On my way home I used T/H and M5 and it didn't seem to upshift like it always does,downshifted fine.It seemed like it wanted to shift faster in T/H than before instead of taking the rpms up and then shifting,no slipping or anything like that either.Could the tranny have learned different shift pattern towing my trailer without T/H on my initial trip up and now I have to tow again and remember to turn it on and get the trans to learn it again.I just wanna make sure I'm not messing up trans.Also not sure how the trans learns driving habits
 

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If I read this correctly, I believe the difference you are noticing is with the torque converter. In T/H, the torque converter is always locked, thus creating the shorter shifts and keeping the truck in it's power band. Somebody correct me if I'm wrong lol. I think I just confused myself.
 

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You're fine. Once up to hwy speed, there's very little diff with that small of a tow load. Your trans will run cooler in T/H and the truck will perform better climbing with different shift points, along with a more aggressive down shift action when slowing.
 

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Discussion Starter · #4 ·
You're fine. Once up to hwy speed, there's very little diff with that small of a tow load. Your trans will run cooler in T/H and the truck will perform better climbing with different shift points, along with a more aggressive down shift action when slowing.
Thanks! I just got a little nervous,Don't wanna have any issues with such a expensive trans. I thought 9k was pretty heavy load til I read what some people tow with their trucks,haha
 

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No need for T/H mode until you are at 80% or more of your GCWR.

Doesn't hurt anything though, just uses a little more fuel from the extended shifts.
 

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I've actually found the T/H & Manual settings useful for bad weather starts at traffic light, using 2nd gear instead of 1st.
 

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I found a similar scenario while pulling my boat. I really don't need the tow haul mode. It pulls in regular shift without hesitation, Almost like if nothing is back there. In the tow haul mode, it seems to be waiting for more weight. It slows the shift, but there is really no need. I'm towing about 7900-8200 lbs.
 

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I usually turn it on when under 50 mph goes off higher than that. Shifts into overdrives sooner that way.
 
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