Ok so the retarded is new to me. I like it. Not sure it is working correctly. Is it normal for it to initiate when I take foot off of throttle? It seems that some times I coast forever and other times it engages quickly. Please educate me.
Ok I am retarded. Meant retarded.
Retarder is the correct word for it.
When its pulled back(on mine) 1 position or 2nd position it coasts
Pull it back more and its more aggressive as you release the gas
Do you have a joystick? It brake only activation?
Let's see... I'll give it a try. One of the rocker switches on the panel to your left is labeled "retarder." When you switch it on the retarder is enabled. Then when you press the brake lightly the retarder will provide 1/3 of its braking power; press harder it goes to 2/3; press real hard and it goes into full retard. If you have a joystick you don't need to press the brake; just click the joystick back from its first position (no retard) to its last position (full retard). When the retarder is retarding, the light on the retarder rocker switch illuminates. Anyhow, that's how I understand it. Pretty neat system.
There are lots of discussions on the mechanics involved and driving techniques so search around and you'll come up with some great info.
jor
We have joystick. Can't seem to find a constant on how it reacts. Can get down the road and mountain passes fine just don't get when and why it is engaging? Not consistent. Sometime immediately at throttle release other times much delayed.
Are you returning the joystick to the full forward (not engaged) position after each use? Your comment about immediately at throttle release sounds like the joystick is in a medium to high i.e 3-6th retard position.
If you leave the retarder switch on and leave the joystick in any position except all the way up, the retarder will engage when you let up up the accelerator. You don't need to depress the brake. The lower the notch on the joystick the faster the retarder will slow down the coach. Every time you come to a stop, push the joystick all the way up. If you don't want to use the joystick you can activate the retarder with the brake pedal as Jor has explained.
John M.
And has to be zero throttle for it to engage.
Think I got it. Thank You. Will dial in technique on wolf Creek pass Friday!
Just remember that the retarder does cause the transmission fluid to heat up - don't rely on it/ride it alone for steep descents. Downshift as appropriate as well.
Will do thinking 250° for high temp level.
A thought or two that you need to know being new to a retarder and it's operation. If you do start to overheat the trans. fluid from over using the retarder the trans. will start to shed load.(less retarding) What you see on your dash gage can/will be different than what the retarder temp. probe sees. Your coach also has an alarm that should sound if you are getting to the max temp. If you ignore these warnings the trans. will completely drop out the retarder to keep from burning up the trans. Now if you get to the point of dropping the retarder before you are half way down WC pass it till cause you to ruin a pair of underpants.
Pamela & Mike
One other consideration. The lower gear you are in the more braking the retarder will provide. If you are going down a hill and just leave the transmission in 6th, you will get some braking but not as much as you need and your transmission fluid will heat up quickly (as Michelle indicated earlier). When you have played with it for awhile you'll understand the relationship between the gearing and retarder position. If you have a VMS it's gets really interesting.
Just thought of something else that I don't think was mentioned. You shouldn't use the retarder in slippery conditions.
jor
Curious to know what the reasoning is for this? I don't remember encountering this tidbit during readthroughs of the applicable manuals.
We went through Wolf Creek pass twice last summer. The speed limit is 45MPH, I have the speed limit on my citation. I should have used number three position on the retarder joystick and fourth gear instead of using fifth gear. Fifth gear was just too fast for the speed limit. I used fourth gear after getting my ticket.
As usual YMMV.
Bob
But also important to note that DW says I have a selective memory
You don't want just the rear tires locking up. The retarder is not linked to the abs.
The rear end of the coach is the heavy end. If the tires slide on snow or hydroplane they lose traction and the heavy and wants to swap positions with the light end of the coach. There is actually an accident in a passenger bus attributed to the use of retarder in Raine at hydroplaning as a result.
The advice is not to use the retired or in heavy rain or icey /snowy conditions
I did this the first month I owned the coach. Came in hot for what turned out to be a very short rest stop off ramp on East I 20 south west of Abilene. Rain and speed created above conditions and back end broke lose and began slide. Credit my time with my VW and its rear engine as making the difference in keeping control. Lesson learned but really tested my Metropolol script.
Alarm at 250. Load shedding at 300.
As was posted revving the motor in a lower gear helps the retardation.
You will not damage the trans at 250 or over for short periods.
I tested my alarm on purpose several times.
When the downgrade flattened out and I allowed the upshift it took two miles for the trans temps to drop enough to turn off the alarm.
Non issue. Made for trash truck continious medium heating use.
I intermix the wheel brakes just for testing purposes to verify the brakes stopping ability and to give the retarder a moment off.
Either system should be able to almost do a fairly long grade by itself
Where did they stop you? Did they wait until you got to the bottom?
I was headed West and it seemed I was about a third of the way down from the summit. He was in the same spot on the way back through about a month later.
The road was just starting to steepen and I was on the shift pad and the joystick and starting to slow down when I saw the lights in my mirrors.
in a descent with the retarder on, using a lower gear will also keep the engine revs up which will produce more cooling for the transmission cooler.
Also, the retarder will not engage while the cruise control is engaged. (this should be obvious).
Love the retarder.
in a descent with the retarder on, using a lower gear will also keep the engine revs up which will produce more cooling for the transmission cooler.
Also, the retarder will not engage while the cruise control is engaged. (this should be obvious).
Love the retarder.
My retarder is set to work with the the cruise in a zero throttle position it will come on if power is on to the retarder
Call me analog, but I like the toggle switch on the Allison shift console, lower left at arm's length. ^.^d
To me (a rookie) I would prefer the retarder not to engage until I touch brakes. Many times can coast comfortably for awhile and don't need the braking help. To each their own. I will learn the design and follow it's parameters. Still the most confident rv I have piloted by far.
One thing to remember breaktime, you have to be FULLY off the throttle. As our coaches have electronic throttle pedals. It doesn't take much pressure for electrons to flow. It might be the case that when you "thought" you were off the throttle. Your foot still might have been lightly on it for a few moments. You'll get used to it quickly enough.
When on the hiway and I'm not encountering overly steep hills. I always leave the retarder activated when on cruise control as it keeps me from going over the speed limit on a slight down hill grade. Once the coach goes a couple of MPH's over the set cruise speed the retarder will do it's thing and throw the anchor out automatically.
The benefit/problem is that the disk brakes are cold blooded and made for much heavier loads than an early u300 or u320.
So I turn off the retarder normally and use the service brakes to deglaze them in every drive and to keep them warmed up a little.
In traffic if they cool off too much the emergency stopping distance is increased maybe too much.
So I have warmed up wheel brakes and the retarder on on crowded freeways.
Retarder on the second position. Throttle off decelerate with the bumper to bumper traffic down to 10 mph.
As the traffic opens up back to first position then on more open areas turn off the retarder totally.
But the switch to turn on the retarder is next to my seat and without moving I can engage it.
If traffic panic stops in front of me I can turn on the retarder quick enough to help in an emergency.
If not leave it on.
I have the toggle, no joy stick. First two owners lived in Kansas. I have family in Abq and Portland Oregon. Is it worth upgrading to joy stick? What is cost and where have it done. Live in North TExas.
Joystick is 6 position control for retarder that operates independent of the brake actuator. Said another way you can actuate the retarder without actuating the brakes.
Yes, it is very much worth having in my opinion. My recollection is that the parts are in the $600 range and the wiring may already be present in the panel next to the driver.
A quick call to Foretravel will give you the cost of parts and labor.
This is a great thread...only driven my coach about 400 miles so far and still learning the right way to use it. I was leaving it on at all times but last night bringing it home from storage (on city streets) I turned it off and it was more pleasurable to drive...that engagement when throttle is let off..it becomes annoying..especially for the passenger..lol
Mike Minegar, Welcome to Foretravel ownership and the forum. The throttle off activation is a standard across all heavy duty diesels. It was the same with my Jake (compression) brakes on both of my Mack trucks (Mack Engines) and my Kenworth (Caterpillar C15 engine). The compression brakes/retarders always activated at throttle release, Not service brake application.
Like you, I deactivate the retarder on city street stop and go driving as it is a bit annoying and actually quite unnecessary.
Mike,
Many folks have installed a normally closed (NC) 12 volt relay in the retarder circuit to allow usage of the brake pedal to deactivate the retarder - thus coasting is easier to do. The switch is left turned on (though the light will remain off) and the relay shuts off the circuit for you.
The output wire for the retarder rocker switch is looped though a pair of NC relay contacts.. The primary of the relay is activated by looping any 12 VDC source to ground at the cold (non-grounded yet) side of the brake switch. Touching the brakes cause a ground to occur to activate the relay coil.
So, when you step on the brake pedal (for even a short tap) that momentarily releases the relay's NC contacts to break the circuit.
This is the same shut-off action as the red retarder switch causes, only you don't have to use your hand to do it. As soon as you accelerate again the retarder is available because it is already available by the relay NC contacts. The switch's red light will go on and off with the use of accelerator and brake pedals as usual.
I leave my retarder stick in any backward setting that I have preselected and can change the stick position at any time.
Jim
2002 U320
Wolf Creek pass no sweat. Trans temp max 225. Was more of a chore getting up the hill than down. These machines are awesome best rv driving experience ever. I do encounter something strange when we left this am. When retarder would activate air pressure dropped into alarm levels 70 psi would keep falling until switched off retarder. After everything up to operating temp no problems back to normal and ideas?
Thanks Joey
Joey,
You may have had the air dryer purge could have been stuck open but this wouldn't have anything to do with the retarder use. How long has it been sense the dryer has been serviced?
Here is another thought that is directly tied to your retarder use. Your retarder air valve could have had either stuck open or had a piece of trash holding it open causing loss of air. Even wide open though your compressor should be able to keep up so this is remote possibility. If it somewhat corrected itself after it was used a while the trash/bug may have been expelled. Here is a link to what you will be looking for on the end of your retarder accumulator tank. Allison retarder air valve (http://www.foreforums.com/index.php?topic=31477.msg277542#msg277542)
Just so happens this post was to clean the remains of a dirt/mud dauber that was causing a similar trouble, you could here the air leak but never lost enough air to cause an alarm. If you find that the exhaust of the valve is dumping air you may be able to give it a tap with a hammer to get it to close till you can give the valve a cleaning.
Pamela & Mike
Thanks for link will check it out. Just installed reman air dryer after scares of failure. Certain it is tied to retarder system.
I'm not that technical, care to explain how it is tied? ???
I am learning but from my driving experience with the FT retarder is air actuated and also released. Watching pressure gauge it drops with retarder engage and can hear it release with deactivation either throttle or speed.
Came to a 14% down grade on Rt 12 south of Torrey, Utah, yesterday. Four miles of being thankful I have a retarder that works!
Ok here is more info just returned from 2000+ mile trip. Seems retarder acts up in am. Today much worse. But we are home. When apply brakes and retarder is supposed to engage. It either lights up and engages or it lights up and can hear air leak drops air pressure fast but no help in deceleration from retarder. Retarder does not engage. I think this maybe a solenoid not sure. I can hear problem it is up front somewhere. Also question if it is solenoid because at engagement I am obviously opening solenoid and losing air. Don't know enough about how it operates. Again. Thanks for any and all help. Saw 3 Foretravels on our Journey thru TX, NM, CO and OK.