Front End Diesel

[murraymc]

Can anyone give some pros and cons on front end diesel?

[hermanmullins]

Be sure and take a test drive. The concept is OK, but there can be a lot of noise with a front engine Diesel. Have your wife talk to you and if you can hear without shouting it should be OK. That being said there are times when shouting occurs even when the engine is off. Tiffin make a very good coach.

Herman Mullins

2002 Dynasty 400 ISL

[wolfe10]

Herman,

It is probably most reasonable to think of the FRED as a step up from a gas chassis rig, rather than trying to compare it with a DP.

And, in that light, it has many advantages over the Ford and Workhorse chassis.

But, it is NOT a DP in terms of brakes, suspension, capacity, etc.

Brett Wolfe

[moodier]

Hi;Laughed talking to fellow with an Allegro Front Diesel.Said he really liked it never had to talk to or hear from his wife for the whole trip.Actually Allegro sure seem tohear very little bad about them in contrast tomany of the othere mfgs.

[gbrinck]

Can anyone give some pros and cons on front end diesel?

Compared to a front end gas chassis, it has the diesel advantages - better fuel economy and more torque and horsepower at low RPMs. Brakes, suspensions, solid axle front end, weight carrying capacity, transmission, etc. are similar to an equivalent size gas chassis.

Compared to a diesel pusher chassis, however, the front engine is noisy and nearly all DPs will have air suspension and all the middle and upper tier models will have an independent front suspension rather than a solid axle. The DPs will have substantially more weight capacity and pulling power (can handle a larger car/truck in tow).

[genefisher@sbcglobal.net]

I purchased an Allegro Open Road 35 ft FRED last August and am very satisfied with it. As to diesel noise, that is not a problem with this model. I hear more road noise than I do engine noise. The engine is mounted low in the front and consequently takes up little room in the cockpit and it seems to be well insulated to suppress noise passing into the cockpit. No problem with normal conversation in the cockpit. I have not driven a comparable Ford or Workhorse chassis so cannot give you a comparison.

So far I am getting around 11 mpg on the rolling highways of eastern Texas. Some of our friends have DP's and complain of the same handling problems that I experience with strong winds. I previously drove a 1 ton Duramax PU pulling a 5th wheel with a total GCWR about the same as the Allegro and toad. The PU and 5th wheel handled better than the Allegro does as one would expect. I have not driven a DP with air suspension so I can't really compare it with the FRED but I am not disappointed with the handling of the FRED chassis.

[pianodan]

I have a front engine diesel that was made way before they named them FRED. I've been happy with it, I would prefer one of the FREDS now though, since they sat the engine lower in the frame rails and they increased the CCC. However, that being said, we have logged over 58k miles on ours since we bought it in 2003, I've had a couple of major problems I had to fix (two due to Cummins putting out a flawed product, one due to Allison transmission doing the same), those are corrected now and I believe the coach will fall apart before I wear out the powertrain now. I get from 8.5-11 mpg now, but the new engine is barely broken in with about 11k miles on it.

Engine noise in the cab is minimal, my wife and I can talk over it, no problem. I will be adding a Spicer aux transmission to get a higher final drive and lower RPM (my Allison is a 4 speed), and an exhaust brake to assist my downhill braking in the mountains though. We're happy with our old coach overall, if I fell into some money somewhere though, I'm sure we would upgrade.

[wolfe10]

I will be adding a Spicer aux transmission to get a higher final drive and lower RPM (my Allison is a 4 speed), and an exhaust brake to assist my downhill braking in the mountains though. We're happy with our old coach overall, if I fell into some money somewhere though, I'm sure we would upgrade.

Pianodan,

You might want to call Allison with your transmission model and serial number concerning the addition of an exhaust brake. Some Allison hydraulic/4 speed transmissions do not have lock up converters in all gears. That really effects exhaust braking performance and can overheat the transmission if a strong exhaust brake is applied in a gear with the torque converter unlocked down long grades.

Allison technical help line 800 252 5283.

Brett Wolfe

[pianodan]

Pianodan,

You might want to call Allison with your transmission model and serial number concerning the addition of an exhaust brake. Some Allison hydraulic/4 speed transmissions do not have lock up converters in all gears. That really effects exhaust braking performance and can overheat the transmission if a strong exhaust brake is applied in a gear with the torque converter unlocked down long grades.

Allison technical help line 800 252 5283.

Brett Wolfe

When I talked to Allison about the use of an exhaust brake on my non-lockup torque convertor (the lock-up is listed, but not available), their only concern was the same as the exhaust brake suppliers, that I wouldn't get as much braking performance as I might like. As far as I'm concerned, it would be better than what I have now. The only real effective engine braking at the present moment is in 1st gear, limiting me to about 25 mph on long steep downhill grades, otherwise service brake application is needed much more often. I'm fully gauged up, including a tranny temp gauge which has rarely hit 150 deg f. I have the deep pan on the 545 instead of the shallow pan, when I installed the 545, I wanted the extra fluid and cooling capacity. If, with the exhaust brake installed I could run down the mountain from the Eisenhower tunnel in 2nd gear and maintain 35-40 mph and not have to use the service brake very often I'd feel like it would be performing the task as I would like to have it do.

As a general rule among Allison 4 speed trannys, there were no lockup torque convertors installed on any motorhome applications, and when I talked to the big truck shop at Mills Ford/GM, he told me most of the schoolbus/commercial applications didn't have them either. I was willing to pay extra for one with my new tranny, but there were none available.

[jbric008]

We have a gas Holiday Rambler 2006 37 ft class A. It has a Ford V6 motor. We have not gone many places with it. My husband says that to go across country we would need to get a diesel because he does not want to drive a gas in the hills and mountains etc. I am pushing back on getting a new motorhome. I would like your thoughts on whether or not a gas coach can go across country. My husband says it is hard to drive in hilly areas and he needs a diesel. I have not written anything on these forums before so appreciate your thoughts.

[wolfe10]

We have a gas Holiday Rambler 2006 37 ft class A. It has a Ford V6 motor. We have not gone many places with it. My husband says that to go across country we would need to get a diesel because he does not want to drive a gas in the hills and mountains etc. I am pushing back on getting a new motorhome. I would like your thoughts on whether or not a gas coach can go across country. My husband says it is hard to drive in hilly areas and he needs a diesel. I have not written anything on these forums before so appreciate your thoughts.

If this is a Ford F53 chassis with V10 (not V6), yes many have driven cross country. As with any motorhome, driving in mountains does take some getting used to as momentum is very different than in a car. Only other advice on a gas chassis is to change brake fluid every three years. Hydraulic brake fluid absorbs water and that materially reduces its boiling point.

Brett

[gamoscoso]

We have a 2011 Serrano with a Workhorse 7 FRED. So far ...so good. We can get 13.5 mpg if we drive under 65 mph. The engine is noisy only when you start rolling, especially up hills, once you pick-up speed, noise is low. If the OD kicks in on a steep climb, the two cooling fans go into high speed and make some strange noise.

On a flat road @ 70 mph there is almost no noise.

Heat from the engine does warm the cabin, you need to drive with the A/C full on, especially in hot weather.