CMKetchum

Looking for some suggestions. I have an 09 Express 3500 15 passenger. It has the 6.0 with the 4L80E. The trans has been upgraded, and I have installed auxiliary cooling for it. Van runs great, hauls my family comfortably, and tows our travel trailer OK.
I was wondering if anyone has used a power tuner to adjust shift points and such with theirs to be able to prevent so much down-shift/up-shift while towing.
If I select "D" the van cannot maintain speed and will down-shift and work back up. If I select "3" it has no trouble maintaining speed, but the engine RPMs are high. Which causes the van to take on a bit of a "drinking problem". I am certain that there is plenty of engine power and torque to maintain speeds in "D", but need to be able to adjust TPS triggered shift points. If there was an easy way to install a manual trans, I'd have done that already. Love the van, we camp A LOT, looking to get some better performance out of this beast.

Thanks in advance for any input.

Chris
2009 Express 3500
6.0 V8 gas
15 pass.

canucklehead

Does it not have tow haul mode? The little trailer button on the right side dash? It changes the shift points. Keeps in lower gear longer under load, less hunting in and out. Tweaks a few other things.

CMKetchum

It does have the tow/haul option, which is functional. The difference is noticeable when that it selected. However, I still lack the accelerator travel to pour fuel to the fire without having a down-shift. Without taking on the cost or re-gearing the rearend, I was looking to use a power programmer to make changes, if that is a viable option.

canucklehead

If your load, and speed has the van hunting between overdrive and drive, then gearing is your problem. I don't think a tuner will help. Also, there is a torque converter lockup in there as well, before the downshift to drive.
You don't want the tourque converter to stay out of lockup too much because that creates heat inside the tranny.

Artie1

It simply does not have enough power, tuner will not be able to help... I had my 6.0 tuned by Blackbear and towing performance hasn't changed at all. So when I had this problem with out 40' travel trailer, I ended up swapping the 6.0 with a 8.1 engine. Tons of work and requires body off frame, but in the end was worth it to me.
Other option to consider is going to a GT5 4.10 rear end (and get it with a G80 LSD if you can).

solwav

Agree with Artie1 you simply lack enough power. I have a 2003 6.0 and pull a 28' travel trailer (about 7300 loaded) and a Sailboat trailer (about 10000), the sailboat is pulled from Massachusetts to Key West and back every January. We take the TT out once a month in summer/fall and to Quebec City every Labor day so I have experience pulling up some moderate grades though have never been stuck in 1st gear on a grade but have been in 2nd unable to go faster than 50 mph on some steep grades

The 6.0 can only do so much so unless you can hunt down a Duramax cargo converted to passenger you have limited choices.
Something I have looked into is changing out my 3.91 rear end gears for 4.88s then add a Gear Venders overdrive.
I would notice a significant boost in pulling power and when unloaded should have double overdrive to help offset the higher gears.Unfortunately there is no easy fix, just not many choices if you need to transport 5 or more people a camper and all the associated gear.

There is a member of the forum who hunted down a beautiful black Duramax cargo that was converted to a passenger van that may be something worth looking into. Apparently there is a dealer somewhere in the USA that specializes in Duramax conversion vans.

Best of luck and have a great camping season.