Learning the the retarder useage

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Learning the the retarder useage

March 26, 2020, 12:15:10 am

Ok. Still learning how to drive this beast. The previous owner said he leaves the retarder on 2 for all driving. I have it there now and works good. I'll be pulling a 4500 lb trailer and wanted some opinions on this
Thanks

Re: Learning the the retarder useage

Reply #1 – March 26, 2020, 07:08:32 am

When you have the retard on when you let off the gas petal the retard kicks in and starts slowing you down. You will not be coasting. You can tell when the retard is engage when the light is lit.

Re: Learning the the retarder useage

Reply #2 – March 26, 2020, 09:10:33 am

It's fine to leave the retarder on if you don't mind the deterioration in fuel economy. Personally, I enjoy being able to coast when I can do so safely.

Re: Learning the the retarder useage

Reply #3 – March 26, 2020, 09:20:26 am

When I'm in heavy traffic I operate with the retarder in the #6 position (max) in case some nitwit does something stupid in front of me.

Re: Learning the the retarder useage

Reply #4 – March 26, 2020, 09:32:15 am

The trouble with leaving it on is that the cruise disengages every time the retarder activates. I use cruise always except in rain, traffic, or mountains.

Re: Learning the the retarder useage

Reply #5 – March 26, 2020, 10:12:37 am

My retarder has a on/off switch, when on the first part of brake peddle travel controls the amount of retard. Very lite touch of brake peddle will engage retarder very little retard. It is easy to feel and control the amount of retard with the brake peddle. There is no other way to operate my retarder. I like it.

Pat,

Re: Learning the the retarder useage

Reply #6 – March 26, 2020, 10:16:27 am

Mine is a 6 speed retarder. I'll leave it off unless in traffic or downhill. The big question is what position out of 6 due you like to use around town and downhill. I'll experiment but wanted your inputs
Thanks

Re: Learning the the retarder useage

Reply #7 – March 26, 2020, 10:37:00 am

I leave the retarder in the off position unless I am using it and then I pull it to were I need it. I use is like a brake peddle and mostly
only use the brakes when the retarder kicks out when I'm just about stopped. I don't like surprises and in slippery conditions if
the retarder is in the on position it can be dicey.

Re: Learning the the retarder useage

Reply #8 – March 26, 2020, 11:13:03 am

Dan, As you can see there are various ways to use your retarder. After you experiment and get some experience using it you will find what works best for you. No mater how you end up using it, you are going to love it.

Re: Learning the the retarder useage

Reply #9 – March 26, 2020, 11:23:45 am

And the best answer is: "There is no single best way for all conditions/all drivers".

Change how you use it based on the conditions as well as your preferences.

Re: Learning the the retarder useage

Reply #10 – March 26, 2020, 12:24:44 pm

Even with the joystick in the "0" or off position, IF your rocker switch is "on" the retarder will still work on three different levels that are determined by the brake activation pressure switches. The harder you press on the brake the more retardation applied by the retarder.

Re: Learning the the retarder useage

Reply #11 – March 26, 2020, 12:50:56 pm

My 97 was modded so that the cruise control does not disengage it's function. Makes a good speed controller as it comes on when you exceed your cruise set speed.

If I want to coast down a grade at that point I pull the retarder switch back to zero. Still works on applying the service brakes.

When we first got this coach the brakes had a lower pressure D2 controller.

Plus the pads did not contact completely as the calipers bushings and pads and rotors were worn and allowed the pads to not contact the rotors squarely and the pads and rotors were down on stopping power.

Rebuilding the brakes completely lessened the need for the retarder itself.

The service brakes were worn enough to require periodic hard application during drives to warm them up.

Plus leave the retarder in the on position in traffic and where cross roads entered the highway.

Not as necessary now.

With a 110/130 cut in/cut out pressure D2 controller installed and the best condition brake parts installed the service brakes are close to what the original owners experienced. Much easier to drive safely. Much "stronger." Less pedal pressure is needed to produce the same stopping effects.

Or just use more retarder as the conditions require and/or your brakes wear or get hot on long grades

Re: Learning the the retarder useage

Reply #12 – March 26, 2020, 01:22:40 pm

Whichever one you have the joystick vs the rocker switch are 2 different ways of retarder use.The joystick at the higher positions
prduce much more trans heat then the switch type.

Re: Learning the the retarder useage

Reply #13 – March 26, 2020, 01:38:16 pm

Excellent info. Now I understand the principal and usage
Thanks again

Re: Learning the the retarder useage

Reply #14 – March 26, 2020, 01:58:06 pm

Quote

Even with the joystick in the "0" or off position, IF your rocker switch is "on" the retarder will still work on three different levels that are determined by the brake activation pressure switches. The harder you press on the brake the more retardation applied by the retarder.

This is the key. When the switch is on the retarder will always work when you press the brake pedal. It doesn't have any effect on anything until you hit the brake. The joystick just makes the retarder more versatile with six incremental levels of control.
jor

Re: Learning the the retarder useage

Reply #15 – March 26, 2020, 02:02:57 pm

Quote from: Johnstons – March 26, 2020, 09:32:15 am

The trouble with leaving it on is that the cruise disengages every time the retarder activates. I use cruise always except in rain, traffic, or mountains.

Just unplug the brake light relay for the retarder, found in the compartment below driver (sometimes at the driver feet under dash). Problem solved.

No all FT's had brake lights activated via retarder. Was a FT option when I installed the joy stick for customers, before they became standard..

People say they then don't have brake light when decelerating, but I always have my foot on the brake a little anyway, when stopping.

It always applied the aux brake in my Jeep, but now it doesn't.

Driven many thousands of miles, in all kinds of conditions, including heavy L.A. traffic. No issues.

Chris

Re: Learning the the retarder useage

Reply #16 – March 26, 2020, 02:14:49 pm

Just have to ad that after putting on 40,000+ miles on a retarder equipped coach, I much prefer the recent addition of a joy stic. Coming down the siskiyou pass ( 6% for 5 miles ) 2 days ago i was able to use the retarder independent of the brake pedal. Loved it.

Always before I would HAVE to use the brakes on that long grade to get the retarder even engaged. The result was higher engine rpm, higher transmission temp and hotter brakes.

NOW ( adding joy stic ) I still need to watch engine rpm, gear selection and trans temp,, BUT now I can rely on the brakes for back up instead of heating them up unnecessarily. I've also used that joystick numerous times in other scenarios.

My take..." if you have the retarder and don't have the Allison joystick GET IT. Unless of course your travels only take you through the flatlands. ( although the js will slow you from 70 to 30ish without the brake pedal quite effectively).

Re: Learning the the retarder useage

Reply #17 – March 26, 2020, 02:35:07 pm

Alternating the brakes and the retarder can extend your speed down grades considerably.

I down shift first to raise engine rpms. Then use the retarder until it gets to around 235 range then turn it off and use the brakes keeping the retarder in reserve. It's temp drops maybe 10 degrees every couple of minutes.

The retarder audible warning is premature in my opinion at 250. My garbage truck fleet guys ran way over that always.

Not suggesting anyone do such a thing but the reserve is there if needed.

Load shedding starts at 300 degrees. Notice your dash trans temp gauge goes to 400?

There is no lower range gauge either.

Re: Learning the the retarder useage

Reply #18 – March 26, 2020, 03:46:11 pm

I use the retarder exclusively when descending grades and if the retarder is going to get too hot I slow down. I keep the brakes
for emergency. I didn't know they come without joy sticks, I agree if you don't have one get one.

Re: Learning the the retarder useage

Reply #19 – March 26, 2020, 04:03:02 pm

In 1988 the retarders were brake actuated only. As far as I know the joy stick had not been invented yet

Re: Learning the the retarder useage

Reply #20 – March 26, 2020, 04:08:40 pm

I leave the retarder switch on, nothing on the lever for normal driving. This will help with braking. It the lever is back then any time you go to a closed throttle the retarder comes on. If you are on cruise control with the lever back and go over the top of a hill the throttle goes to zero, cruise shuts off and retarder comes on.

Coming down long grades, lower gears first, one or two notches of retarder, service brakes last and then only when the coach is going straight if possible. Slow down before the curves. Retarder temps 235 or less is what I shoot for. 250° is OK for regular trans oil for a sort while. 300° for anything other than synthetics is way too hot. You are not driving a garbage truck. Don't treat it like one.

Re: Learning the the retarder useage

Reply #21 – March 26, 2020, 04:19:19 pm

Most here are switching to synthetic over time.

Re: Learning the the retarder useage

Reply #22 – March 26, 2020, 04:20:17 pm

I had to install the joystick on our 1995 U280.
Worth the money and was a simple install.
As stated before, a very nice improvement to driving in the hills and mountains.

Re: Learning the the retarder useage

Reply #23 – March 26, 2020, 04:26:17 pm

I intentionally ran my retarder down interstate 5 in so cal from Lebec, ca to Grapevine, ca at the bottom of the grade. At 250 the alarm went off. This was at normal speed down the grade. Was at the bottom at the time.

Turned off the retarder and within 3 minutes the alarm and light went off.

15 miles the trans temp was normal.

Re: Learning the the retarder useage

Reply #24 – March 26, 2020, 04:54:31 pm

Around town and in traffic, I keep the the joystick mostly at 3, On the highway, I keep it mostly at zero so the cruise control works. Before braking in traffic for for turns, I pull back on the stick before using the brake pedal. On downgrades, I first select a lower gear, then use as much retarder as needed to keep the speed and RPMs in line, occasionally applying the foot brake as needed,

And always watching the retarder temperature on my VmsPC. The alarm goes off right around 250.

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