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
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.
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.
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.
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.
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,
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
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.
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.
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.
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.
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
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.
Excellent info. Now I understand the principal and usage
Thanks again
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
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
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).
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.
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.
In 1988 the retarders were brake actuated only. As far as I know the joy stick had not been invented yet
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.
Most here are switching to synthetic over time.
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.
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.
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.
And, for those just learning to use the retarder, on those long downgrades, ALWAYS keep the engine RPM at the higher end of their approved RPM range.
This uses 0 fuel (throttle closed) and turns the water pump faster which keeps transmission temperature lower.
And, a little more digression for those new to the "sport". Each engine has several RPM numbers that you need to commit to memory (determine from your engine manufacturer for your engine serial number):
Peak torque RPM-- do not operate the engine under anything but light load below this RPM
HP RPM-- RPM at which max HP is generated
Governed RPM-- highest rated engine speed UNDER LOAD
Max no-load RPM-- in most cases higher than governed RPM and is the max safe RPM with throttle closed-- like with retarder on.
In general, I try to keep max RPM with throttle closed with retarder on between HP RPM and governed RPM, but if very steep long grade, you will do no damage going up to max no-load RPM. Said another way, on those long steep grades over-temp on service brakes or transmission temperature from retarder is less desirable than operating the engine at higher RPM.
Hi Brett,
Always love your posts!
How would we find out those rpm numbers?
Is there a way to look it up?
I have a 98 325 Cummins with 3060r Allison.
Brett nailed it!!! Thanks Brett
Understand those numbers can be found on the Cummins website. All you need is your engine serial number.
Interesting all the high temps I read on here with retarder use. Have towed my loaded race car trailer, and Jeep down big grades, hammering the retarded.
I have never seen temps past 205-210, on the gauge or the sileverleaf. The trans and silverleaf are pretty close to the same temps, up and down, and follow the engine temp. (not on down grades)
Am I missing something? Or maybe I am cycling it right, on and off, and using part brakes.
It all seems to work fine.
Chris
Two different temp senders I understand. One in sump? The other in the retarder?
That is what I am thinking too. I believe there is some deal, where you can move sender at the trans.
My over tempt never goes off, except for back when I had the issue with it, where it went off periodically (even cold)
But I fixed that, by changing that sender in the trans.
Have transcend, not going to worry about it.
Chris
Use PID 120 on your VMSpc for retarder temperature. It generally runs about 5 degree above transmission temperature and can go from 185 to 235 in seconds when the retarder is engaged.
Tom, I was unable to find those numbers on the Cummins web site. I don't doubt that they are in there somewhere but I sure could not find them. I was, however, able to get three of the numbers off the engine data plate. The only one I am lacking is the max no load RPM.
Sooooo, on the Cummins 300, 8.3 what rpm is max going downhill working range
I understand our 97's does not report #120 out of data plug? Is that incorrect.
I found that I really had to pay attention to the transmission temperature on the Vms. So I go along depending on what the temperature is. As others had said on the highway bring the joystick all the way back. It will cause minimal drag when you come off the gas. And really heavy traffic though I bring it up towards the end. That way as soon as I come off the gas it starts braking me. That's some serious safety. We all know that as we get older our reaction times are much less. The retarder really helps with that. Invaluable in my opinion.
Correct, at least for my '97. It does not report Retarder temp on the data bus. I have to rely on Trans temp, which lags the Retarder temp a little bit, and may report a few degrees cooler but has been close enough.
Question,if you just have the rocker switch and add the joystick can you still use the rocker switch?
The more I read about this subject, the more I like the simple 3 position setup we have (no joy stick).
If the cruise is on (engaged), the retarder is disabled.
If the cruise if off (not engaged) and retard switch is on, retard begins as soon as you let off the throttle.
Coming out of WV last week our speed would creep up higher than I was comfortable with, using full retard.
Service brake to slow the coach down, then downshift 1 gear.
55MPH (comfortable) the rest of the way down, no brakes, no trans or engine temp worries.
Not having to monitor temps I can relax and watch for possible troubles outside the coach, either ahead or behind.
Works for us.
Thank you Rodger
Ours is the old dos look, black box, with Cat engine.
Chris
Yes, the one in the retarder is the one I replaced. There is also one for the gauge in the sump line.Replaced that one 1st. The retarder one is the one that was setting off false alarm.
Pic inside retarder
Pic of gauge sender (crappy pic)
I agree Phranko. 55mph is max downhill and still feeling comfy. I only drive 65 on the flat max.
The more I read about this subject, the more I like the simple 3 position setup we have (no joy stick).
If the cruise is on (engaged), the retarder is disabled.
If the cruise if off (not engaged) and retard switch is on, retard begins as soon as you let off the throttle.
As to the above quote, definitely not the way ours works.
With the joystick in the "off" position, or "0" which is forward on mine, the stick has no bearing on the operation of the retarder. If the rocker switch is on the retarder works off of the service brake pressure switches and deactivates when speed is below 10 mph. The retarder will drop out the cruise control if activated and the cruse control can not disengage the retarder. If the joystick is in any position other than "off" then the retarder is activated when the accelerator is released. The joystick does not override the rocker switch operation, the rocker must be "on" for the joystick to work.
Maybe this will clear up what seems to me to be some confusion about retarder operation.
Yes. We added the joystick 15 years ago. When the rocker switch is off, all retarder functionality, including the joystick, is disabled. Rocker on = all retarder functions on.
Be aware that retarder joy sticks can be mounted so that forward is off, back full retard, OR the reverse where forward is full retard. We all get used to our own setup and don't realize that others are reversed.
Relating to tranny temp dash gauge, our sensor is in a 1/8" NPT hole on the large diameter coolant lines that come from the forward side of transmission. If the sensor is on the return from tranny cooler, dash gauge will read slower and lower. We relocated our dash sensor to the line going to the cooler, so now we see realistic quick & higher temp readings. Also, after a long down-hill run where gauge got into 300 degrees, the cooler works so well, we see temps sink low very fast. So, the input to cooler line location is very responsive.
I have heard of this, and want to do it. Can you post a picture please.
Thanks Chris
A couple of photos, Chris
Our lower forward face of transmission has two large diameter elbow fittings that direct tranny fluid hoses up and back to large tranny cooler. One hose is transmission out and other is return to transmission.
Our return elbow was probably drilled by Foretravel factory for the factory 1/8" NPT sender.
Because the two elbows are next to each other, hose runs would bump into to each other so factory had one hose looped down so it was the lowest part of the drive train, vulnerable to damage.
During a transmission maintenance visit when fluid had been drained we eliminated the down loop and had a the other elbow drilled to relocate the temp sender.
Found these related postings, oldest first:
Erratic coolant temperature & transmission temp gauge change (https://www.foreforums.com/index.php?topic=2123.msg7129#msg7129)
Retarder - hose rerouted (https://www.foreforums.com/index.php?topic=4262.msg16816#msg16816)
Experience Wanted - Speedometer install (https://www.foreforums.com/index.php?topic=7115.msg30673#msg30673)
Retard feature pros and cons (https://www.foreforums.com/index.php?topic=10124.msg46384#msg46384)
Allison Transmission Temp Sensor (https://www.foreforums.com/index.php?topic=13640.msg76365#msg76365)
Retarder 101 (https://www.foreforums.com/index.php?topic=16138.msg102164#msg102164)
Transmission temp gauge (https://www.foreforums.com/index.php?topic=25475.msg201924#msg201924)
Jan and Richard,
A good rule of thumb is that max no-load rpm is usually 20% above governed rpm.
Jake Brakes rule ..sorry alll....could not help myself lol
Here's what I got out of this thread.
Disconnecting the brake light actuation when the retarder engages may stop the trans downshift command from being sent to the trans.
The auto downshift command adds the additional cooling and engine compression retardation to the retarders input
Can be done manually but I noticed the trans ocassionally would auto downshift under occasional heavy loads on the retarder Function.
So as I see it my personal choices choices are to not have the trans auto downshift when the retarder engages or not have the retarder kick off the cruise control.
So trans downshift or retarder with cruise on.
Anyone have a thought on how to build a work around? I there a way to make the trans think the brakes are applied so the trans downshifts but not kick off the cruise?
Am I wrong? Does those whose brake lights work have their trans downshift readily? This is a finesse observation I think.
You may have to drive a similar coach with the relay on and then off. Just to compare the trans downshift pattern.
I choose to manually downshift the trans to raise the engines rpms and to have the retarder work on cruise versus it kicks off the cruise versus auto downshift the trans?
Not correct, my trans downshifts as normal when retarder is activated.
Everything functions the same, just the brake lights don't activate, which causes my toad brake to activate (really hard on toad brakes)
My trailer brake controller also doesn't activate when the retarder activates (which saves trailer brakes, when applied with every hiccup in the road).
Here is picture of the relay on mine. You can simply unplug it, and try it both ways, which I did.
Come up, I will take you for a ride
Chris you have a 3060r trans. It's capacity may signal a downshift differently than my 4060r?
Then again it may not.
May require hooking and unhooking the same weight and model engine and trans to define this better.
The engine/trans/programming for your 3126 cat/3060r vs my m11/4060r might be different. Or the trans sensing function varies with the engines ability to self retard. Or specific programming?
A knowledgeable Allison Cummins man might know. May have to ask my dealers shop manager/owner coming up
My trans doesn't automatically shit down when I apply the retarder and my toad brakes only work off the brakes and I will have the
trailer brakes only come on when the brakes are applied. I will wire the trailer brake controller to the brake light switch and if there
is a feed back from the retarder I will put in a separate air switch for the trailer brake controller.
Old guy, does your retarder work on cruise?
No, I have to manually operate the retarder and it will pull it out of cruise if the throttle is closed. I don't know if it could be set up
to operate on cruise, that would have to be done by an Allison teck.
Is the retarder an Alison part
Yes. The "R" after your transmission model number signifies the Allison transmission retarder.
So, may be an Allison MD3060R, 3000R, etc
You will find a metal embossed tag on the driver's side of the transmission.
Thankfully ours doesn't either. >:D
One thing I might add. On early 97's, the joy stick was being installed mostly after market. I installed lots of them for customers at the FT dealer. Wasn't standard from factory unless ordered I think.
Our 97 is a June 1996 build date. It wasn't till I believe the next model year (98) that coaches came standard with the joy stick. Bob may know more then me about that, as he was in sales.
I would imagine ours was installed later, so wiring may be different then factory. This may be why some have brake lights activation, some don't.
I actually struggled with figuring out how to do what I did with the relay, there was just no wiring on my diagrams about how it was configured. Truth be told,I stumbled across the fix by accident.
The joy sticks at the dealer, came as a kit pre-wired from FT's factory. To remember which way the stick went, I burned into my mind "back for whoa, and froward for go" ! Stuck with me till today. Same as with air conditioning. Which hose is suction, which is pressure. "Big blue Bertha sucks"
Chris
Those that have installed the joystick themselves, can you tell me in specifics how you plugged in the y harness. What color was the connectors under the dash?
Sagre
I have the stick forward to stop. Lever is closer to my hand for its resting position. Retarder switch is next to it on the inside position
Odd, my 1998 retarder works in concert with the cruise control. After a decent it just carries on.
Dan, to keep it simple. Just think of it like the throttle or the brake peddle. You can apply more or less while underway as needed. Don't be afraid to experiment.
Retarder not slowing you down enough? Then go from 2 to 3 or 4. What ever you need. On my 98 320. The retarder coming on does not deactivate the cruise. I suspect that the cruise/retarder interaction must be adjustable. As some say that their's does turn off.
Experimented pulling my 20 ft cargo with retarder. Moved to position 3 and noticed the tranny temp climb immediately . So. Tranny temp is what I'll drive by as others have told us
Best advice I got when we bought our coach. Never failed during our trip at altitude out west. Thanks Brett.
When outside significant altitude I simply leave retarder on but rarely use joystick.
Downshift. Watch rpm. Really watch retarder temperature. Get a vmsPC or blue fire to see retarder temps.
When I first got my IH45 and I had the cruise on, it would shut off after a period of time. I was trying to figure out what was causing the cruise to disconnect and I was trying to pay attention to when it disconnected. I was thinking the brake light switch was bad, a loose wire and who knows what else I was thinking. Turned out the retard switch was on and joy stick was not all the way forward. When ever I would go down a hill where the cruise would let the coach coast the retard thought that it needed to brake and then disconnected the cruise.