Uphill Shifting Question

[DWR]

I've been pulling a 5th wheel camper for about five years - this will be the first year with the Gryphon with 87 custom towing. I had the camper out last week to get it inspected and I live in very hilly southwestern PA. Because it is so hilly, I typically tow with O/D off. Most of my trips with the trailer are to Penn State games in Central PA, so I do not see any flat land for the 4 hour trip. I noticed when going up the hills that it was shifting directly from 3rd gear / TQ locked to second gear instead of shifting first from 3rd gear / TQ locked to 3rd gear / unlocked. Is that part of the custom tune that Bill and Cody have put together? Is that better on the tranny to shift to 2nd then shifting to 3rd gear / unlocked?
It seems to me that the last few years when in stock mode it would shift to 3rd gear / unlocked before shifting to 2nd and that sometimes that is all that was needed to crest the hill at 55-60 mph. But if it's better in the long run to shift to second locked or unlocked I will learn to get used to the rpm increase on these southwest PA hills.

[Jackpine]

You ask an interesting question, DWR. I also tow, and I've never noticed if my truck shifts directly from 3rd locked to 2nd. Since I don't pull as much weight as you (about 3,600#) plus the stuff in the bed and often 4 people, I tend to tow with the OD on. (I've talked about this in past posts - as long as the transmission activity is low, I leave the OD on).

But, I know the transmission will go from OD locked to OD unlocked before shifting down to 3rd. Then, it kind of seems to me that my transmission does what yours does between 3rd and 2nd, but I could be wrong. I think maybe it has a lot to do with the grade of the hill and the weight being moved though. Here in Arizona we have several hills with 7%+ grades that are 10-12 miles long. I'm always in 2nd gear going up those hills, and I try to maintain 65 mph, since they're on the Interstates, where the speed limit is 75.

- Jack

[DWR]

Yeah, I wll have a better idea in about a month when it hits the highway for the first time with Gryphon. When I got the trailer inspected last week I only had it on country roads where the speed limit ranges from 45-55 mph.
I really like the way it pulls and shifts from a dead start - big difference over stock. I've been driving the truck since new - and I've always listened closely to every little noise - especially when towing - so I will just re-adjust my ears when pulling hills. I imagine it is much better on the tranny to shift to 2nd and pull the hill then to try 3rd gear unlocked and have to shift to 2nd anyway. Thanks Jack
-Dale

[jcperform]

I also lock out the OD in hilly areas with my 06 screw 5.4 towing a 7 x 7 x 18
5000 lb toyhauler to prevent constant shifting and keep temps down. It seems to me most of the time it would downshift from 3 locked to 2 locked,....if I leave the OD engaged it will shift in and out of lockup and the trans temp goes up as does the oil temp,...BTW my flat towing temps with deep trans pan, synthetic oils, 25% antifreeze with Water Wetter, 3:55 gears, 29.4" tires are as follows:
trans(flat loaded) 150- 165 hills 192 max
CHT 200 218
EOT 204 238 max uphill 110 ambient
Coolant 205 224 max

I have 600 lb tongue weight, friction antisway, rear axle sway bar,...very stable

This is all with Bill's custom tow tune,...

cheers !

[Habbi98]

Jcperform, I am just curiosity what your fuel economy is when pulling your trailer? I am running a similar setup and am getting what I think is horrible fuel economy, I am getting <7 mpg.

[Longshot270]

To help readjust your ears you could set one of your PIDs as COMM GEAR. This is Commanded Gear and says not only which gear you are in but also the status of the torque converter.

[stl454]

Habbi98

I have a2010 supercab max tow with 5.4 and 3.73 gears. Gryphon with 87 towing tune. On average I get 10mpg running 65mph. If lots of hills it gets 8.5 to 9 mpg.