Alison Tranny Retarder vs Jake Brake

[Jon Wehrenberg]

Gary,

I'll take a 180 turn here.

If you find a coach you like don't make the decision to walk away from it because of the retarder.

You see how most of us feel, but it does not have to be a show stopper. First of all a retarder works. It assists in braking and it will help control speed going down hill. A Jake allows the driver to be less attentive, but to make a retarder work effectively and not overheat you as the driver has to plan ahead and that is not a bad thing. I get the best compromise by leaving it in the second position and slowing down slightly just before the steep downhill. That keeps the bus going downhill at a reasonable speed and it keeps the temperatures very low.

With a Jake you can be going fairly fast, and put it in the high setting and downshift and it will do a great job and you don't have to worry about it, but these buses are more than just retarders.

[Jon Wehrenberg]

Information on the Allison Transmission and retarder can be found here by opening the PDF file.

http://www.allisontransmission.com/p...s/OM3349EN.jsp

Here are some highlights that may prove of interest. With a retarder service intervals are cut in half. If you use Dextron you need to change fluids every year or 12,000 miles instead of 25,000. Transynd is impacted similarly, but has longer oil change intervals, depending on some other factors such as flilter types.

The retarder force will be reduced if the fluid overheats. I mispoke earlier. It appears that the computer will eliminate the need to worry about temperatures.

Speaking of temperatures: they vary depending on where the temperature reading is taken. The sump oil temperature maximum is 250 degrees F. More details are available at the link above.

Instead of having to take the bus to Allison to deal with harsh shifting, it appears by using the correct inputs we can clear it so the transmission can reprogram (self teach) itself.

The file is 94 pages with lots of good information.

[Toy Box]

Same experience here. Last two buses had jake brakes... two cycle detroit 8-92 engines. Current bus has retarder... four cycle detroit. I think the jake was idiot proof as far as operation. The retarder took a few trips over the Rockies before I was comfortable with it's operation. Today, I really don't have a preference.

[garyde]

On my way out to Santa Fe, it was brought to my attention that I was riding my brakes and black smoke kept poping from my exhaust. Well, it was the Trans. retarder. I had left it on and any time I let my foot of the gas, it would slow the Coach down and then I would apply the gas. So, you have to be more aware of what you are doing. I was told you could raise the temp up to 290 degrees no problem. But I can not remember who at POG II told me. It is great for slowing down coming off the freeway, or having to make a rapid deceleration. I have to watch it on long down hill slopes.
My Country Coach Lexa has a 3 stage Jake and I liked that a lot also.

Finally, I really like my Liberty . Gary