When to use overdrive

[DIAMONDS]

I just bought my first motorhome, a 2006 Fleetwood Pace Arrow gas-powered coach. Can someone explain the overdrive -- when to use it and when not to use it? Also, the Pace Arrow has a grade brake that I would say you put on when going down hill, correct?

[wolfe10]

Welcome to the FMCA Forum.

When asking a mechanical question, it helps state what chassis you have. Since you specifically mention "grade brake" I assume you have a Workhorse chassis.

GRADE BRAKE:

From the Workhorse website: Downhill descents are now easier on the driver and easier on the brakes with Workhorse’s new Transmission Grade Braking. All 2005 W Series chassis (W20, W22, W24) will feature this as a new standard system at no additional cost.

The driver activates TGB through an illuminated dashboard switch. Then he or she engages the feature by depressing the brake pedal and releasing. The transmission automatically downshifts a gear and starts to control the motor home’s speed.

So on a steep decline the driver just needs to step on the brakes to let his transmission automatically provide a smooth, safe ride downhill. This avoids unnecessary wear on the brakes while providing a reassuring sense of control to the driver. No stress, no sweat: TGB does the work."

OVERDRIVE:

The higher the gear (including OD) that you can run in without lugging the engine, overheating or "hunting" the better for economy.

Definition: "Hunting" is the repeated shifting back and forth between gears caused by the engine not quite being able to maintain the higher gear, but easily able to accelerate in the lower gear. So, for example, the transmission would hunt, shifting 5-4-5-4-5-4.... up a hill.

Brett Wolfe

[DIAMONDS]

Welcome to the FMCA Forum.

When asking a mechanical question, it helps state what chassis you have. Since you specifically mention "grade brake" I assume you have a Workhorse chassis.

Yes, it is a workhorse, so would you always drive with the overdrive on all the time or only in mountain areas? I dont now if this is true; others told me you get less MPG when you use O/D.

[wolfe10]

yes it is a workhorse so would you always drive with the overdrive on all the time or only in mountain areas I dont now if this is true others told me you get less MPG when you use O/D

You will get BETTER MPG in OD-- gas engines are more efficent at lower RPM with higher loads. But that does NOT give the most HP.

I would drive in OD all the time on flat country (and let the transmisison choose the correct gear-- unless the transmission is hunting). In mountains, switch out of OD for better performance.

Brett Wolfe

[DIAMONDS]

Thank you. Now I understand the overdrive. I have one other problem -- it's posted in the Electric section of the forums.

[rkestenb]

I drove my fist mountain downhill recently and used my grade brake as it stated below. Should the grade brake hold at the initial speed for the entire trip down the mountain? My coach gained some speed and I had to start using my regular brakes also which then caused my grade brake to disengage.

[rkestenb]

I drove my fist mountain downhill recently and used my grade brake as it stated below. Should the grade brake hold at the initial speed for the entire trip down the mountain? My coach gained some speed and I had to start using my regular brakes also which then caused my grade brake to disengage.

[rkestenb]

I drove my fist mountain downhill recently and used my grade brake as it stated below. Should the grade brake hold at the initial speed for the entire trip down the mountain? My coach gained some speed and I had to start using my regular brakes also which then caused my grade brake to disengage.

[wolfe10]

I drove my first mountain downhill recently and used my grade brake as it stated below. Should the grade brake hold at the initial speed for the entire trip down the mountain? My coach gained some speed and I had to start using my regular brakes also which then caused my grade brake to disengage.

It is likely on steep down-grades that you will have slow down (service brakes) and manually down shift to a lower gear than that selected by the grade brake feature.

Similar to what those with larger Allison transmissions in diesels have to do-- with, say a 4th gear pre-select, they have to use the service brakes to slow down enough and use the down arrow to select a lower gear.

Again, your safe speed of descent is really UNRELATED to curves, etc. It is based on a gear/speed that holds YOUR SPEED IN EQUILIBRIUM. That speed will be faster than loaded 18 wheelers and slower than empty ones.

Brett Wolfe

[bobruss@yahoo.com]

You indicated that all 2005 motorhomes on the W24 Workhorse Chassis have the "grade brake". I have a 2005 Monaco LaPalma on the W24 and it does not have this feature....(no switch on dash for this).......???

Is it possible my coach was built on a 2004 chassis even tho its a 2005? How do I tell?

I generally just shift down to a lower gear (on a steep grade) and use the regular brakes sparingly to keep the rpms in a decent range so as not to overtax the engine and transmission (on the premise that brakes are easier and cheaper to repair).

[wolfe10]

You indicated that all 2005 motorhomes on the W24 Workhorse Chassis have the "grade brake". I have a 2005 Monaco LaPalma on the W24 and it does not have this feature....(no switch on dash for this).......???

Is it possible my coach was built on a 2004 chassis even tho its a 2005? How do I tell?

I generally just shift down to a lower gear (on a steep grade) and use the regular brakes sparingly to keep the rpms in a decent range so as not to overtax the engine and transmission (on the premise that brakes are easier and cheaper to repair).

Yes, it is quite possible/quite common for a chassis model year to be prior to the coach model year.

You check by calling your chassis maker (Workhorse) with your Workhorse VIN.

And if you are resorting to using the service brakes because of fear of over-reving the engine, the transmission ABSOLUTELY will not allow the engine to over-speed.

And if still concerned, a safer approach is to slow down and use a lower gear-- one that holds your speed in EQUILIBRIUM without using the service brakes.

Brett Wolfe

[seawolf77@aol.com]

Yes, it is quite possible/quite common for a chassis model year to be prior to the coach model year.

You check by calling your chassis maker (Workhorse) with your Workhorse VIN.

And if you are resorting to using the service brakes because of fear of over-reving the engine, the transmission ABSOLUTELY will not allow the engine to over-speed.

And if still concerned, a safer approach is to slow down and use a lower gear-- one that holds your speed in EQUILIBRIUM without using the service brakes.

Brett Wolfe

The year the chassis was made should be posted along with gvw weight tables, should it not? I have a 1999 Winnebago Vectra and it has chassis manufacture date, vin and gvw as well as each axle weights.

[hopeynsonny@hotmail.com]

rkestenb

The way my grade brake works is when going down a hill using your grade brake each time you step on the brake it will shift to a lower gear to slow you down more. The grade brake will not let you shift low enought to over rev the engine. My grade brake has never released by putting on the brakes only when you give it gas. Hope this helps a little.

Good Luck

Sonny

[rkestenb]

This is the first question I have asked on this web site and I would really like to thank everyone for their help. It should make it safer on the road for me and anyone in front of me on the way down the mountain!

[pearlpchef@cox.net]

Can anyone tell me if you should use overdrive when towing a Honda crv. I have a 33' Winnebago Voyage with a workhorse chasis.

Thanks,

Paul

[wolfe10]

Can anyone tell me if you should use overdrive when towing a Honda crv. I have a 33' Winnebago Voyage with a workhorse chasis.

Thanks,

Paul

As long as the transmission is not "hunting" (repeatedly up/down shifting between higher and lower gear) YES.

Brett Wolfe

[pearlpchef@cox.net]

As long as the transmission is not "hunting" (repeatedly up/down shifting between higher and lower gear) YES.

Brett Wolfe

THANKS BRETT,

I APPRECIATE YOUR INPUT,

PAUL PLANTE

[mtylenda@yahoo.com]

Grade Brake on the Allison as used on Workhorse Chassis,may be left on at all times. All it does is perform a down shift to a lower gear, same as if you did a manual downshift. The transmission senses input and output shaft speeds, and decides if a down shift is needed. You need to lightly apply the service brake to activate the Grade Brake. It will release when the transmission senses it can up shift, or you manually turn off the Grade Brake.

The OD can be left on at all times unless the transmission starts to hunt. I have towed my CR-V thousands of miles with OD on.

The ECM (Engine Control Module) & TCM (Transmission Control Module) talk to each other, you cannot over rev the engine. FYI TCM is on top of the ECM on the motor.

You can tell chassis year, 10th digit of VIN is the year -- applies to all makes of chassis

You should also register at Workhorse.com so you can see any campaigns open or closed on your chassis.

[traderdude04@yahoo.com]

We have the 6-speed Allison with the grade brake, and we leave the grade brake switch on all the time. It is especially useful for our mountain driving, but it works well and downshifts FAST during emergency braking. I do like hitting the brakes once, and the transmission will downshift to a lower gear, and if I hit them again, it downshifts again (if the Allison agrees that the RPM is within range).

As far as overdrive is concerned, I keep our overdrive dash switch set to "on" which is the 6th speed. Sometimes I will switch it off and travel in 5th gear if I see we will be hunting between gears on a long gradual uphill stretch.

[WGPuckett@aol.com]

Not to change the subject too far but we have a 2008 Fleetwood Bounder on an F-550 frame with a V10 Triton gas engine. Last year Ford changed the way the Tow/Haul setting works. When in Tow/Haul it will automatically downshift when going down hill with the cruise on. We have driven the mountains of Arizona, New Mexico and Colorado and almost never needed to use the brakes. If not in cruise all you have to do it tap the brakes and it will downshift. Tap again a bit harder and it will downshift again. The only reason we don't use it all the time is because it locks out the O/D. Would be nice if the settings were separate. But we can deal with that.

It's a great feature. Definitely saves brakes and makes mountain travelling much safer.