Retard feature pros and cons

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Retard feature pros and cons

July 10, 2010, 12:56:04 pm

As a new member and actually a Foretravel admirer for years(I don't have one yet) I'm curious to know not how this system works but how well it is liked compared to other systems you more experienced?

Thanks
Gootie
Madison,WI

Re: Retard feature pros and cons

Reply #1 – July 10, 2010, 01:22:32 pm

Gootie,

I love my retarder system and use it all the time. Here is how I understand the systems work.

The adequate but least powerful system is the exhaust brake found on most diesel motorhomes. It is either on or off. When on, it will slow the coach down on most hills such that you will need to turn it on and off as you descend to maintain the speed you want.

The Jake engine brake in some higher end motorhomes turns the engine into a compressor and is more powerful in slowing the coach than the exhaust brake and may have two levels of operation instead of just one. This is the system used on big trucks and is the one cities post signs saying no engine brake to stop citizens from hearing the noise they create.

The transmission retarder is the most powerful of the three and needs good cooling for the transmission fluid as it will heat up when retard is in operation and is why big trucks do not prefer it.

My Foretravel has always dissipated the heat as they apparently planned for it when designing the cooling system.

It is armed to work when you turn the retard switch on. As you step on the brake, the first pressure engages 30% of the retarder ability. Additional pressure will engage 60% and even harder pressure will bring on 100% retard.

If you have the joy stick and the retard switch on, there are six levels of retard available without stepping on the brake. This allows you to vary the retard to match the steepness of the hill to hold speed where you want it.

Stepping on the brake with the retard switch on works the same with or without a joy stick.

With the joy stick full forward the coach will coast with the accelerator at idle. With the joy stick back from full forward, the retarder will engage at the set retard level anytime the accelerator is at idle,i.e. your foot off of the accelerator. If you are on the accelerator asking for power the retarder is off.

If I have erred here or missed something, I am sure one of the others with help out. It sure works good for me.

Re: Retard feature pros and cons

Reply #2 – July 10, 2010, 01:25:56 pm

Gootie,

My first Foretravel (36' 1989 OREG or Oshkosh Rear Engine Gas) had no retarder or exhaust brake. It didn't stop so well, but I guess I didn't notice it because I had nothing to compare it to. I have since had a 1999 36' U-270 and currently own a 2000 U-320 40' (4010 or single slide unit).

Both those coaches have the retarder and I absolutely would not ever have a large coach now that didn't have a retarder.

Pro's

Incredible stopping power

Smooth engagement

No Noise

Adjustable with Joystick and can be used independent of brakes

Con's

Expensive if purchased as an option (actually expensive to build into the price of a Foretravel too...)

Transmission Temps need to be monitored during prolonged use (going down a grade for a substantial distances in the mountains)

I have inadvertently hit the joystick and put one notch of "retard" into use while going down the road. Found it because cruise control kept disengaging, Guess you could say both the transmission and the driver were

"retards"....

My good friend Dave Head can fill you in on the pluses of exhaust brakes, he has had two Foretravels with them installed, but I believe given a choice he would much prefer the retarder.

Tim Fiedler 2000 4010

Quote

On 7/10/10 11:56 AM, "gootie"
As a new member and actually a Foretravel admirer for years(I don't have one yet) I'm curious to know not how this system works but how well it is liked compared to other systems you more experienced?

Thanks
Gootie
Madison,WI

Re: Retard feature pros and cons

Reply #3 – July 10, 2010, 01:32:46 pm

Thanks guys
I had road tested a new 40 footer at factory in 2000 and was much in awe of the Foretravel .
My day is coming

Gootie

Re: Retard feature pros and cons

Reply #4 – July 10, 2010, 02:09:41 pm

Another pro to having a retarder is that your brake pads will last a whole lot longer.

Another pro is faster stopping in emergency situations.

We are so pleased and fortunate to have bought a coach with a retarder. It offers a great sense of safety to us.

Re: Retard feature pros and cons

Reply #5 – July 10, 2010, 02:42:29 pm

We have nothing to compare it to. We just know the Allison Retarder works great. While traversing the Rockies last year, we crossed the continental divide 8 different times. It was not only a breeze with the retarder, it offered a real sense of security going down some of the long grades.

Re: Retard feature pros and cons

Reply #6 – July 10, 2010, 03:02:40 pm

So now that a few members have included their very helpful responses I have to ask about the trans temps in heavy use. Do most Foretravels have trans fluid temp gages? Seems like the only way to tell if some limits are being approached.
Again, I really appreciate this info as we will be "pulling the trigger" someday and this brand of motor coach is the desired home

Thanks
Gootie

Re: Retard feature pros and cons

Reply #7 – July 10, 2010, 03:20:18 pm

Yes, all diesel Foretravels have transmission temperature gauges.

The typical diesel instrument cluster will have this gauge as well as the usuall suspects as fuel, water (coolant temp), oil pressure, Front & rear air tank pressure (psi)[these are needed for the air operated brakes as well as the air spring suspension].

Many owners either have added additional gauges such as a pyrometer (measures turbo temperatures of the exhaust gasses used to drive the turbine) as well as turbo boost (measures the current vacuum levels at the turbine providing the pressurized air for combustion and horsepower enhansement); or have added aftermarket monitoring systems availabe for the electronically controlled diesel engines. Anexample of such a monitoring system is the SilverLeaf brand.

Re: Retard feature pros and cons

Reply #8 – July 10, 2010, 03:51:34 pm

I actually haven't met anyone who does not like the Allison retarder on

Foretravels.

It was one of the MAJOR reasons I purchased a Foretravel as I pull a trailer and I like the redundancy as it concerns stopping my rig.

It works amazingly well and would most likely only be out performed by an electric retarder.

I can tell you that if you get a Foretravel and it has a retarder on it, you should use CAUTION in applying it in a panic stop. It will, along with your brakes, STOP YOU NOW.

Re: Retard feature pros and cons

Reply #9 – July 10, 2010, 04:21:57 pm

Hi Gootie, I have a Detroit 6V92 350 H.P. with the "Jake Brake" system, with two levels of braking power. Previously I had a "Bluebird" with transmission retarder. Both work well, The braking power of the retarder is stronger, however heat is created. The Jake Brake does use engine compression to slow the vehicle, this does no harm to the engine nor does it create any additional heat. The "Noise" created is well muffled by the motor home exhaust system. With the S.O.B. (some other brand) coach I did have a heat dissipation problem...

Re: Retard feature pros and cons

Reply #10 – July 10, 2010, 10:37:14 pm

My 96 U270 has the button. I read somewhere in the literature that it only costs $400 to convert it to the joy stick. Does that sound right? Is it worth it (does the joy stick work that much better?)

Is there any reason not to have it "engaged" under "normal" driving conditions. I had an incident driving through Albuquerque, rush hour traffic, needing to change lanes so looking for an opening, looked up and my lane was a parking lot. I did get it stopped in time, but it would have been nice to have the retarder helping.

Re: Retard feature pros and cons

Reply #11 – July 10, 2010, 11:27:45 pm

Gayland,

You keep giving us more opportunities to spend your money. I think the major difference between the button and the joystick is that you have greater flexibility in choosing the degree of retardation. When driving in heavy traffic (which I try to avoid at all cost) I keep my retarder pulled back 3 notches. That way as soon as I let up off the accelerator I get some immediate slowing down.

Re: Retard feature pros and cons

Reply #12 – July 11, 2010, 12:00:49 am

On our coach the dash transmission temperature gauge was OEM connected to temperature sender screwed into the large diameter elbow on the transmission fluid returning from transmission fluid heat exchanger.

So our gauge used to read the hot fluid AFTER it was cooled down.

I moved the sender to the hot out-flow (going to the exchanger) on the back on the transmission.

Now, when under full-retard, transmission temperature gauge climbs pretty steady up toward 300 degrees on a long downhill mountain run.

And drops back to 180 degrees like stone when we reach the bottom of the hill where we turn retarder off.

The sender has a 1/8" pipe thread male fitting.

Re: Retard feature pros and cons

Reply #13 – July 11, 2010, 12:05:51 am

Gootie, we just got back from our first trip to the Rockies in our 1997 U 270. Left S.E. Texas & went to Silverton, Colorado. about 1200 miles, crossing Raton Pass, N.M., La Veta Pass, Co. Wolf Creek Pass, Co. Coal Bank Pass, Co. and Molas Pass, Co.
Not knowing what to expect I didn't even bring a tow car. It was a breeze both pulling the hills and going downhill thanks to the retarder. This is our first motorhome so I can't compare it to not havng one. The only problem I had was a heat alarm for a short while, but not sure why. The alarm went off after a short while.

Jim Monk
1997 U270

Re: Retard feature pros and cons

Reply #14 – July 11, 2010, 08:38:24 am

Gayland,

Expect about $600 to have the joy stick installed. We recently added it to a 1997 U295. About $375 for the parts and $240 for labor.

We haven't used it much in Texas, but expect to use it on our trip to Montana. We made a similar trip in a 37' "other brand" and used the exhaust brake a few times. I expect better control and greater comfort with the retarder controlled by the joy stick.

Re: Retard feature pros and cons

Reply #15 – July 11, 2010, 09:26:03 am

Quote

My 96 U270 has the button. I read somewhere in the literature that it only costs $400 to convert it to the joy stick. Does that sound right? Is it worth it (does the joy stick work that much better?)

Some additional information on installing a joystick.
http://beamalarm.com/Documents/installing_joy_stick_retarder_control.htm

Re: Retard feature pros and cons

Reply #16 – July 11, 2010, 09:37:44 am

Quote from: Jim Monk – July 11, 2010, 12:05:51 am

Gootie, we just got back from our first trip to the Rockies in our 1997 U 270. Left S.E. Texas & went to Silverton, Colorado. about 1200 miles, crossing Raton Pass, N.M., La Veta Pass, Co. Wolf Creek Pass, Co. Coal Bank Pass, Co. and Molas Pass, Co.
Not knowing what to expect I didn't even bring a tow car. It was a breeze both pulling the hills and going downhill thanks to the retarder. This is our first motorhome so I can't compare it to not havng one. The only problem I had was a heat alarm for a short while, but not sure why. The alarm went off after a short while.

Jim Monk
1997 U270

This is the type of comment that I was looking for and I now have to ask are you using synthetic tranny fluid?
It sounds as though we all should be monitoring the outlet temp as I understand the tranny fluid life expectancy is shortend by higher temps. Does the use of synthetic change the lubrication capabilities under these extremes?

Re: Retard feature pros and cons

Reply #17 – July 11, 2010, 10:09:39 am

Gayland, I do not use long life trans fluid but rather change the std fluid at required intervals. I drive about 8,000 miles in two years, so I change it and the filter every two years. I use the retarder 100% of the time. I leave the rocker switch on...period. Then whenever I use the service brakes, the reatrder helps stop the vehicle according to the 33%, 66%, 100% based on depth of pedal application. I also use the joy stick to slow down the coach even of flat roads to slow down any time I have to. This serves to reduce the amount on wear on the service brakes.

Re: Retard feature pros and cons

Reply #18 – July 11, 2010, 10:21:25 am

Great information - it was actually gootie that asked about the synthetic oil, but only because he beat me to it. I see that the PO used synthetic so I'll probably stick with it.

Barry, do you think your temp unit was installed by mistake, or are they all installed after the cooler? Maybe their theory was/is as long as you're supplying cool oil to the tranny, there's nothing to worry about???

George - money not a problem, I'm setting up a site so you all can contribute, cause I know you all want me to be happy

Re: Retard feature pros and cons

Reply #19 – July 11, 2010, 10:55:40 am

Gents
This question of where to monitor tranny fluid temp could be answered by an Allison rep?

Re: Retard feature pros and cons

Reply #20 – July 11, 2010, 11:24:20 am

I see only pros no cons. The transmission retarder was the number one reason (followed by 99+ more) for my chosing Foretravel.

Living in Los Angeles, it use the retarder a lot. When traffic slows, i reach for the joystick even before my foot hits the brake pedal. I sometimes make it all way down the Grapevine, the Baker Grade, and truck-restricted sections of Highway 49 without using the foot brake. And I do watch the transmission temperature, but have never seen an appreciable rise.

Tom

Re: Retard feature pros and cons

Reply #21 – July 11, 2010, 11:27:54 am

Quote

On our coach the dash transmission temperature gauge was OEM connected to temperature sender screwed into the large diameter elbow on the transmission fluid returning from transmission fluid heat exchanger.

I had asked James Triana some time ago:
Is the sensor monitoring the output of retarder (350 degrees max)
or sump pump (250 degrees maximum)
He told me that our Gauge monitors the sump temperature (250 degrees max).

Re: Retard feature pros and cons

Reply #22 – July 11, 2010, 11:34:31 am

Barry, that makes sense to me as if the available fluid is already at 250 at the sump, that would indicate that the amount of heat absorption by this temp fluid is near its max when exiting the retarder with all those additional BTU's. It would also indicate if the trans cooler is performing its duties of discipating those BTU's back into the atmosphere.

Re: Retard feature pros and cons

Reply #23 – July 11, 2010, 11:37:44 am

Hi Gayland,
I added the joystick control to my 1997 U 320. It was a unplug, plug, tie wrap, type of installation. It is the BEST modification I have done to the coach. A can't leave home without it deal.

Re: Retard feature pros and cons

Reply #24 – July 11, 2010, 12:47:23 pm

We have Silverleaf and I have seen the trans temp increase to as high as 240 degrees on long hills. Is the max temp 250 degrees?

Also, I read somewhere that one should not use the retarder in the rain? Reason?

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