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Topic: 2000 U270 Allison Transmission retarder (Read 634 times) previous topic - next topic

2000 U270 Allison Transmission retarder

Looking for some advice or someone near Palm Bay Florida that is really familiar with the retarder system. I will be making the move soon to Alaska from Florida and will be towing approximately 7500 pounds heading from Florida to Albuquerque NM then north the Fairbanks and want to make sure it's all in great working order before this trip. I used it prior to purchasing and it seemed to work like a champ then I had the problem of no pressure building in either air tank. I then replaced the D2 Governor which didn't fix it so then found the air dryer leaking as fast as the compressor was pumping. I replaced the dryer assembly and made the voyage home. Everything worked great however the retarder doesn't seem to work.
Darren and Chris
2000 Foretravel U270

Re: 2000 U270 Allison Transmission retarder

Reply #1 –
You should have a joy stick and a switch.  The switch has to be on.  The amount of retard is based on joy stick location.  I have seen some were it goes from front to back and were they go from back to front.  If the switch is on and you have the joy stick in the off position, the retard will work when you press on the brake.  If you move the retard joy stick without touching the gas or brake you can get different levels of retard.

Now that you know this what is it doing or not doing.

If your switch has a light on it, it will be on when the retard is working.

If you have the retard switch on and the joy stick not off, while using the cruse control the cruse will disengage when it is trying to coast.
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: 2000 U270 Allison Transmission retarder

Reply #2 –
The first time I drove it i had switch on then control all the way forward for the least amount of retard and when I would let of the throttle to coast to a red light I would move joystick to rear one click at a time then I would feel the transmission retarding more each click towards the rear...now when I let off the throttle in same scenario it doesn't make a noticeable deceleration even though the light on switch illuminated when I pull handle to the rear...
Darren and Chris
2000 Foretravel U270

Re: 2000 U270 Allison Transmission retarder

Reply #3 –
Have you checked trans fluid level?And when was the trans fluid changed?
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: 2000 U270 Allison Transmission retarder

Reply #4 –
Last year trans fluid was replaced and I will check the level again
Darren and Chris
2000 Foretravel U270

Re: 2000 U270 Allison Transmission retarder

Reply #5 –
Most accurate fluid level check is with the shift pad, but, only after transmission is fully up to operating temperature.

All described in your Allison manual, but here is what you do:

With transmission fully warm (may take 50 or more miles), stop on level ground.

Put transmission in neutral. Park brake on.

Push the up and down arrows at the same time.

Allison display will bring up O L and begin counting down.
It will then display OK or + or - and a number (of quarts).

You can turn off the engine, or push N to return to regular mode.
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: 2000 U270 Allison Transmission retarder

Reply #6 –
Darren,

You know "that thing" (retarder control air valve) that had air leaking out of it (that you have ask about) then the air leak stopped. 

Air leak

When coach is running is air escaping out the vent line like before? If so this can cause the retarder not to work due to trash under the seat in the valve.  If this is the case you may be lucky enough that the trash blows out while you are exercising it causing the retarder to magically start working.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: 2000 U270 Allison Transmission retarder

Reply #7 –
Quote from: Pamela & Mike –
Darren,

You know "that thing" (retarder control air valve) that had air leaking out of it (that you have ask about) then the air leak stopped. 

Air leak

When coach is running is air escaping out the vent line like before? If so this can cause the retarder not to work due to trash under the seat in the valve.  If this is the case you may be lucky enough that the trash blows out while you are exercising it causing the retarder to magically start working.

Mike
lol I'm trying to figure this quote thing out...but as for the air leak that's the first thing I tried with no leak at all. I did however unplug it and plug it back in while troubleshooting it and have also double checked to make sure it was in fact fully seated and it is as well. Heck maybe I just have to learn the system better
Darren and Chris
2000 Foretravel U270

Re: 2000 U270 Allison Transmission retarder

Reply #8 –
Darren,

It could be something like a loose wire plug or you may have a code down. You need to check for any codes for the transmission.  If you have a code then we may be able to narrow it down.  This is done through the shift pad. IIRC here is the way we get the codes to come up on the windows of the shift pad. This is kind of an addition to Brett's post on checking oil level.

 Ignition ON, engine OFF

1. On Allison shift pad hit UP and DOWN arrows at the same time.  This will bring us OL (Oil Level) Engine has to be running and trans up to temp. for this to work.

2. Hit the UP and DOWN arrows again at the same time.  This will bring up d-1 (for diagnostic code 1).  If no code, it will flash d-1 - -.  If there is one, it will flash a number code. 

3. If there is a code, hit the MODE button to bring up the d-2, etc. 

4. Continue pushing MODE until you get the -- for no more codes.

Report your findings.

Pamela & Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: 2000 U270 Allison Transmission retarder

Reply #9 –
Quote from: Pamela & Mike –
Darren,

It could be something like a loose wire plug or you may have a code down. You need to check for any codes for the transmission.  If you have a code then we may be able to narrow it down.  This is done through the shift pad. IIRC here is the way we get the codes to come up on the windows of the shift pad. This is kind of an addition to Brett's post on checking oil level.

 Ignition ON, engine OFF

1. On Allison shift pad hit UP and DOWN arrows at the same time.  This will bring us OL (Oil Level) Engine has to be running and trans up to temp. for this to work.

2. Hit the UP and DOWN arrows again at the same time.  This will bring up d-1 (for diagnostic code 1).  If no code, it will flash d-1 - -.  If there is one, it will flash a number code. 

3. If there is a code, hit the MODE button to bring up the d-2, etc. 

4. Continue pushing MODE until you get the -- for no more codes.

Report your findings.

Pamela & Mike
I will have to look at that tomorrow when I get home from work. Thanks buddy
Darren and Chris
2000 Foretravel U270