Trend overdrive issue

[montanamark]

Hello all. I am new to this forum. We just purchased a new Trend 24 ft gasser with a 280 hp v6 and 6 speed tranny. We love the coach but for some reason it will not stay in overdrive for any length of time especially using cruise control. We travel in flat Florida and with the slightest headwind it downshifts to 5Th regains speed and upshifts to 6th for awhile. Then repeats. Tow haul mode does not help. Owners manual seems to say if you experience frequent gear hunting to minimize heat buildup choose a lower gear. So. Question. Is it ok to travel at highway speeds in day 5th for long duration?? Appreciate and feedback. Love the coach otherwise.

[Cooperhawk]

Not sure what trans you have. On our Allison there is an option that will let the motor lug down quite a bit before shifting. We use it on flat ground.

[luvlabs]

You need to visit your local Dodge/Fiat Service department and have them take a look. On level highway it should not be gear hunting when cruising at highway speed.

You are not overloaded or towing something are you? You might get that behavior if you are but it still seems like it shouldn't gear hunt.

[Old Crows]

Need more data!!!

What do you mean by "highway speed"? How fast are you trying to go when this happens??

Headwind..... How much of a headwind????

It is a Pentastar V6. Torque is 260 ft.lb @ 4400 rpm.
Transmission is a Chrysler 62TE. 5 gear is 1:1 direct. 6 gear is .69:1.

The “fourth prime” gear, similar to the Chrysler 45RFE/545RFE’s “prime” gears, was used for kickdowns only. When moving from a lower speed, the transmission used the standard fourth gear; but, once in a higher gear, the transmission could kick down to “fourth prime” instead of fourth, to make the shift feel smoother.

https://www.allpar.com/mopar/transmissions/62TE.html

[montanamark]

Thanks for this info. I do not think I have that option on this tranny. But they do have a tow haul mode that is supposed to lend some assistance. We still like the coach a lot!!!

[montanamark]

I'd say like avg 65-70 mph. 10mph headwind or so. I notice it does not gearhunt nearly as frequently if I slow to 60 at say 2000 rpm. I am told the tranny is adaptive meaning it adjusts to your driving habits. Maybe I am expecting too much power performance from this 6 cyl hauling a 9500 lb box on its back. Slower speeds may be part of the solution. Yrs ago I had a 30 ft Georgetown powered by a Triton V10 and once it locked into overdrive it pretty much stayed there. This Trend having so much less hp but still being pretty heavy may well be a little underpowered. Thus my issue. Do appreciate the info.

[Old Crows]

Thanks! Of top of head. 65 + 10 headwind = 75. Add a slight grade. 9K+ lbs. Aerodynamic drag sux power. That is probably more than it can handle with a 0.70 overdrive.

Best thing is to find a comfortable speed a few miles slower. Or, try 5th gear direct drive 1:1 to get slightly higher on the torque curve.

A lot of this is programming in the power management computer. Some will just hang in there...others will dump down a gear or two in a hear beat.

Just try a bit slower speed and see if that helps.

[montanamark]

ok I'll try that and advise if it helps. My belief is it will. I had contacted Promaster customer service thinking they would route me to a transmission engineer or service tech with knowledge on this issue .... but no luck. All they do is reach out to a dealer and ask them, pretty much same thing I have done. So this Forum is actually a better source of info and we do appreciate the info!!!!.

[workhorsed]

Hi, not sure about how well this will work for you but with my 8.1l and 4L85E set up there are only four gears and the downshift from OD to third is pretty dramatic. Something I learned was to anticipate the hill and gently add just enough throttle to slowly gain speed at the same rate as the momentum is falling off. The trick is to avoid the down shift by maintaining the momentum.

I cruise at 2200 RPM, approx 62 MPH. On a long hill I will ever so slowly accelerate up to 2500 RPM or so to maintain the energy. My OBDll data shows considerably less fuel is consumed as compared to a 3300 RPM down shift over the same distance. This tactic also allows you to stay out of the truck lane!!

I'm not sure if it will work with a small displacement engine but without a word of a lie this has improved my annual fuel consumption from 35 to 38 liters an hour to 28 to 30 Lph. With fuel at a buck thirty a litre this is huge!!

I learned this half a century ago hauling gravel, not to save fuel but to avoid three stick downshifts in my Diamond T. Cheers W.

[al1florida]

Originally Posted by montanamark

Hello all. I am new to this forum. We just purchased a new Trend 24 ft gasser with a 280 hp v6 and 6 speed tranny. We love the coach but for some reason it will not stay in overdrive for any length of time especially using cruise control. We travel in flat Florida and with the slightest headwind it downshifts to 5Th regains speed and upshifts to 6th for awhile. Then repeats. Tow haul mode does not help. Owners manual seems to say if you experience frequent gear hunting to minimize heat buildup choose a lower gear. So. Question. Is it ok to travel at highway speeds in day 5th for long duration?? Appreciate and feedback. Love the coach otherwise.

Yes it will be OK to drive all day in 5th gear. In fact if you are shifting in and out of 6th gear every few miles it would be better to drive in 5th.

Tow/haul mode is supposed to change the shift points to up shift at a little higher RPM than normal mode. To me this means that once the computer downshifted to 5th it should stay there a little longer before shifting back to 6th. I doubt it would change the downshift point. Note: Tow/haul mode usually gives some automatic downshifting for engine braking when going down hill. Check your owners manual for details.

I would think it is pretty normal for that small, probably higher revving, engine to downshift to 5th in a bit of a head wind. You also may be driving into a very slight uphill grade. Not enough to be really noticeable, but enough to add a little load to the engine/transmission.