Skip to main content ↑ ↓
Topic: Retarder stopped working (Read 460 times) previous topic - next topic

Retarder stopped working

On a recent trip back from Colorado, the retarder in our 97 U295 stopped working, or at least the lighted switch stopped working.  We were already in Texas so it wasn't really needed by then.  When home, I checked the relay which appears to be working. 

I pushed both arrow buttons on the shifter panel and I got what I believe to be codes, but could not locate those in the Foretravel manual.  The first one to show up was: 7 0, followed by 0 L, followed by - -.  Like I said, I couldn't find anything in the manual and don't know if they mean anything.  I have never checked the codes before so they could have been in there for a while. 
Bruce & Jen Evans
Montgomery, TX
1997 U295 36'

Re: Retarder stopped working

Reply #1 –
OL is oil level.  I believe you need the engine running and transmission up to temperature to get the proper reading (7-0 indicates sump temperature is too low).

The full error code listing is in the Transmission section of the wiki Allison Transmission  Start with page 19 for the WTEC III era coaches.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Retarder stopped working

Reply #2 –
Search on the Forum for the terms "retarder solenoid" and "retarder accumulator".  These items have often been the cause of retarder problems.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Retarder stopped working

Reply #3 –
To access the Allison diagnostic codes:

Ignition on/engine off.
Push up and down arrows at the same time.  That will bring up O L for oil level.
Push the up and down arrows again at the same time.  that will bring up d-1.  If there is a stored diagnostic code, it will show the code.
If there is a code, record it and push the mode button to bring up d-2.  Continue until you get d-"whatever" and - -.
Turn off the ignition to return to regular shift pad use.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Retarder stopped working

Reply #4 –
Quote from: wolfe10 –

Push the up and down arrows again at the same time.  that will bring up d-1.  If there is a stored diagnostic code, it will show the code.


Brett,

No codes were stored.
Bruce & Jen Evans
Montgomery, TX
1997 U295 36'

Re: Retarder stopped working

Reply #5 –
Quote from: Michelle –
OL is oil level.  I believe you need the engine running and transmission up to temperature to get the proper reading (7-0 indicates sump temperature is too low).


Thanks
Bruce & Jen Evans
Montgomery, TX
1997 U295 36'

Re: Retarder stopped working

Reply #6 –
Switch light bulb burned out? Voltage at switch terminal? Could retarder be working without light on? Retarder can work with brake pedal lightly pressed. Wire fall off bottom of retarder switch?

Re: Retarder stopped working

Reply #7 –
Easy to confirm if the retarder is working.  Pull lever all the way back, lift throttle, coach will almost come to a complete stop with no brakes.
George Mann
2002 U320 #5934
2017 Rubicon
2013 BMW GS
Waterford MI

Re: Retarder stopped working

Reply #8 –
Quote from: Brucep86 –
"the retarder in our 97 U295 stopped working, or at least the lighted switch stopped working. "

If you're not sure , take it out for a test drive, as Geodmann stated use the retarder lever in the full activation position after letting off the throttle, then you will know if its not working or just a defective lamp. Let us know what you determine.
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: Retarder stopped working

Reply #9 –
He may just have the switch and no joystick,let's get that verified.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Retarder stopped working

Reply #10 –
Quote from: John44 –
He may just have the switch and no joystick,let's get that verified.
Coach has both switch and joystick. I never realized that there was a light on the switch, guess I am too busy paying attention to what is ahead of me then looking at the switch.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Retarder stopped working

Reply #11 –
On my 95 U240 the retarder works by light touch on brake pedal.  The retarder switch on dash does have a light and comes on when retarder is used.  The switch on dash is used to  disable the retarder.  I use the switch when I am running hot on engine temp.  I have to drive like old truckers in high ambient temps, don't use retarder, going up and down hills in same gear, using gears to control speeds entering towns.  i love the retarder, but it does increase trans and engine temps when in use.

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

Re: Retarder stopped working

Reply #12 –
We put a small LED on dash so driver can know when retarder is activated. Wired it from the side-dash. Very helpful LED.