YFZPILOT

So I finally hooked up the 5th wheel to go camping this weekend. I must say it was very impressive compared to my 03 Hemi. My truck is a 06 3500 at lb qc 4x4. I had a few issues though, on the way home there was a long steep grade, about 2miles. When I was neering the top a tranny started to shudder about 5-6 times, what could that be. My other question was when cruising on flat groung I felt like truck had some wierd noise (a low whine) and a slight vibration at 50-60 mph, would this be the torque converter locking up? Oh sorry the 5ver is a 12,000 pound toyhauler.

YFZPILOT

Anybody.......?

Dodgezilla

Were you using "Tow/Haul" mode?

Hannibal

My Cummins autos would do that on occasion. I believe it was the torque converter starting to slip from low rpm and low line pressure with the high torque of the Cummins. My solution and it made me happy was to manually downshift to the next lower gear and run 2900rpm up the grade. I emailed Cummins about it and was assured the Cummins 5.9 runs in stationary equipment for hundreds of hours at peak hp full load with no problems. For me it solve the problem if you want to call it a problem. Higher rpm moves more air through the engine for lower EGT, moves more tranny fluid through the cooler for lower tranny temp, and uses gear reduction for less load on the TC as well as higher line pressure from the higher rpm and throttle position. You could pay big bucks to beef up the tranny to "force" it to pull the grades in a higher gear at lower rpm but I personally don't see the benefit. But then again, I don't have a problem with the gas hog running 4200+rpm up the grades in 2nd. Let the gears do the work...

YFZPILOT

That sounds like that is what it was doing, so next time I'll drop her into 2nd on the column and see how she does, thanks.

TonyB

I was really impressed (yse, first tow on new truck) saturday, towing my buddy's boat up to Roosevelt Lake on saturday. Going through Globe, 4 or 5 7% grades, set the cruise control at 0, and let the motor pull through the hills. Near the creast of the hills, it would downshift into third & just keep 60mph.

Going down the back side of the hills was just as fun: The cruise control would engage the jake to control speed. Never touched the brakes!

At one point though, coming home, pulling the hill just leaving Roosevelt, heading towards globe, it went into 3rd & pulled the hill just fine at 2500RPM. Those with EGT gauges, or insight, what might have been my exhaust temps? I do plan on gauges in the next 6 months, byut I'd like to know!

TIA

Tony

barracuda

How much weight were you towing? The higher the RPM's usually equals lower EGT's. I will say compared to my 98', the new trucks (i have an 06' ) run noticably higher EGT's than the old ones. Get gauges, I was surprised how hot these trucks rin.

TonyB

About 4500lb.

Basically 1/3 of the capacity of the truck.

Tony