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Topic: Retarder switch question (Read 620 times) previous topic - next topic

Retarder switch question

Hello,  I have a 1990 Unihome with a 6v92 .  Could someone explain how the retarder switch is used?  Thank you,  Mike

Re: Retarder switch question

Reply #2 –
Leave the retarder switch on all the time unless you have a specific reason to turn it off. Driving on ice would be one of those reasons you'd want to turn it off. Watch your transmission oil temperature gauge when you step on the brake pedal and you'll notice it going up. That's one way to know that the retarder is working. Try not to let the temperature go over about 250 degrees if possible. If it gets too hot it'll discolor your transmission fluid and you'll have to change the fluid, which really isn't a big deal, especially if the retarder saves your life on a steep downhill grade. If you've ever driven with electric trailer brakes you know what it feels like if you hold your foot on the brake pedal until the trailer brakes pull back on your vehicle. That's sort of what it feels like when the retarder is working. Sometimes the red light doesn't light up on the toggle switch for some unknown reason, but you can always tell the retarder is working by the feel and the transmission temperature gauge. Some coaches have a joystick for the retarder. Yours may have the toggle switch like mine does. It works the same in the sense that you step on the brake pedal to activate the retarder with the air brakes. The joystick would allow you to use the retarder alone without the air brakes. The retarder is much more effective than an engine brake or exhaust brake, and it doesn't make any noise, so you can use it in residential areas.
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)

Re: Retarder switch question

Reply #3 –
On my 95 U-240  cat 3116 MD3060R I leave the retarder switch off all the time except when testing/exercising/downhill use.  The switch turns on and off the break pedal function of the retarder.  The light in the switch will lite up when the retarder is functioning and will go out at 5mph when retarder drops out and service brakes stops the MH.  If you use the retarder, watch the tranny temp, it will climb when you use the retarder and drop when not in use.  The higher tranny temp caused by retarder will also cause the engine temp to rise because the tranny fluid is cooled by engine cooling system.

Pat
Pat/Blue Angel
1995 U240 36ft
MC# 16511
Build# 4653

Re: Retarder switch question

Reply #4 –
Quote from: RRadio –
Leave the retarder switch on all the time unless you have a specific reason to turn it off. Driving on ice would be one of those reasons you'd want to turn it off. Watch your transmission oil temperature gauge when you step on the brake pedal and you'll notice it going up. Yours may have the toggle switch like mine does. It works the same in the sense that you step on the brake pedal to activate the retarder with the air brakes.
Hmm, with our Pac Brake, the toggle switch engages the unit and I can feel it start to slow me down. We just came down from 5k to sea level on some steep ones, and the only time I used the brakes was SOB coaches ahead that were riding their brakes! I've done enough "drops" to not even look at the temp gauge that much.
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Retarder switch question

Reply #5 –
Mike, I think you've got an exhaust brake which shouldn't have any effect on transmission oil temperature. I suspect Mbehave has a transmission retarder like my coach has. I think I read on this forum somewhere that the switch on the dashboard is labeled "Retarder" even if it's really an exhaust brake.
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)

Re: Retarder switch question

Reply #6 –
Quote from: RRadio –
Mike, I think you've got an exhaust brake which shouldn't have any effect on transmission oil temperature.

Yup, know nothing other than  I have a "Pac Brake" and the "switch" on the Allison console. I drive down hills with one hand waiting to "hit the switch". The other day, in terrible traffic, I simply noticed red lights, traffic and used the rocker, no brakes.  ^.^d
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'