Peter,
Marathon must have changed the jake/brake light in the later years. Mine does not operate the brake light and works with cruise control as well. ;)
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Peter,
Marathon must have changed the jake/brake light in the later years. Mine does not operate the brake light and works with cruise control as well. ;)
Tom, my brakes lights come on with the jakes, at least the light on the trailer brake controller comes on, so I assume the brake lights are on!
Thanks for the further info. My bus has the DDEC II system, and it is not sophisticated enough to allow user programming of the Jake Brake with cruise control, but the later DDEC III and IV are. You just hook up the reader box and set on or off with cruise control as you prefer.
That points out the one deficiency I see with my set up, while toolig down the interstate and you start descending a little, well, the bus just picks up speed like a ball bearing rolling down a ski jump and before you know it you are doing 85. So, you have to stay alert and kill the cruise on a big downhill. That can be a pain if you are in a place like Interstate 5 in southern Oregon where there are a long series of 10 miles up hill followed by 10 miles downhill. But, clearly, Prevost addressed that on the later busses. Not enough reason to convince me to trade up though.
Thanks again guys for all the important information about Jakes and Retarders. I can honestly say I am only half as confused as I was half a week ago. (just kidding)
Thanks for the info.
Gary
According to the Prevost website, both the Jake brake and the retarder are options on their shells. You can get them either way. I suspect the Jake brake costs more as a factory option.
http://www.prevostcar.com/cgi-bin/pa...tab=powertrain
I personally also prefer the Jake brake. Might be nice to have both! The only downside would be cost.
Peter vS
94 Marathon XLV
I too question why a retarder would be used in place of a Jake.
It is abundantly clear by the maintenance schedule that Allison considers a retarder equipped transmission so hard on the fluids that change intervals are cut in half.
There is a real plus for the Jake. When our granson was little when he travelled with us and we went through tunnels he loved hearing the sound of the Jake. He thought that was great.
See my earlier post. The retarder costs more, much more.
And Peter, The Jake on my Peterbilt is hooked to the cruise. If it can't hold the set cruise speed on a down grade the 1st stage comes on, if that doesn't do the trick the second stage and then the 3rd if needed. All automatically, with no driver input. Towns put up no Jake signs cause Grandma got tired of being blasted out of the bed at 2 AM by "chicken trucks" with straight pipes. My truck has 8" pipes with no mufflers but I've never had a problem cause I know when to behave. :cool: Jacobs Engine Brakes have been around for billyuns and billyuns of miles and work, period. I'm telling you, this is all a plot cooked up by Allison to sell trannys.
It seems clear we would like to have a Jake instead of a retarder, but there is a downside to the Jake that nobody has mentioned yet. A Jake works best at higher RPM.
One thing I have noticed with the retarder is that when it is on and I hit the brakes the retarder aids in stopping power to a noticeable degree. With the Jake, when we got down below about 20 it dropped out and while it wasn't like the coach accelerated, there was a noticeable loss of stopping assistance.
I guess if it could be done Perter's idea of having both would be the ideal.