towing in 6th gear

I do.......My '04 has a New Venture Gear tranny( The old new Process Gear co.) and is almost bullet proof.. I believe they arrive at the max torque rating of the tranny using 6th gear.....Never had a manual trans that you could not haul in the O.D. gear.. Never experienced a heat problem although I would have to say, I don't know how to tell with out a temp guage . But there are no shifting problems when used hard..Shucks this thing is almost a automatic.Amost never have to shift..I live in central NY and use I 81 frequently and only drop 1 gear on Nanticoke Pa hill and when going north sometimes 1 gear on the pull up Ravine Pa hill (north of Lebanon).. Change oil in rears/T Case/trans every 15 or 20 thousand. Using Mopar oil.....
Do you have the NV or the new design trans ?

I also tow in 6th most of the time. Haven't noticed any problems and didn't see any restrictions in the Dodge owner's manual.

Nv5600

The NV5600 is the cast Iron cased tranny. Yes, this is what I have. The problem being is that the 6th gear is in front of the cluster. I believe this was done due to the issue the NV4500 (5 speed) had with the nut basking off in 5th gear. However, this is not as strong a design. There is talk about adding a Overrive unit to the tailend. Then you could tow in 5th overdrive and empty in 6th overdrive. Some have just added the fast coolers to the PTO covers (Geno's) for additional cooling. Some say to add an additional quart of oil. I tried that and the tranny run hotter then before so I removed the extra oil and run at the bottom of the fill hole. The other problem is the NV5600 is not made anymore , so parts are rare. I try to use only 6th on the flat open road and drop down to 5th sooner then I would normally. The other thing to say is I have 3.73 rears. So I can drop down to 5th sooner without high rpm's. This is a little more shifting but that is not so bad. On the back roads, 5th is just right for driving along.

The cooler would be a good idea as well as a guage.I'm not going to worry about the strength of this tranny for a long while.. I have the 4,11 gears because that was DCs max towing weight limit for that year..Engine spins a little more than I like at 65 mph , but it's tolerable. I don't think spare parts will go out of stock just because the stopped making the trans.. But time will tell.. And then again ,perhaps, in the future the new owner may have to deal with this .. 6 sp automatic coming .......

I let Mr. Allison just do his job unless I'm in a place where it is hilly with a lot of corners.

Overdrive!

Towing with a slushbox is boring. Anyone have experience with overdrive units? Like gearvender or us gear. Mount to the tail piece of the tranny and electric shift.