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My Bus is now home where the Buffalo Roam
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Harry,
The boat anchor part happens when you have the Jake on in the low gears. With the Jake on in second gear, you better have your seat belt on!
Glens, are you saying the 5-speed can be programmed to automatically downshift like our 6-speed transmissions? I’m just curious.
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Harry, 1700 is not an effective RPM for the jake so if you downshift and get the RPM up in a lower gear such as 4th it should be noticeable.
Some hills easily overcome a jake and you have to be ready to use the brakes if the engine RPMs start exceeding 2100. If you select a gear lower than the speed allows I do not think the transmission will shift into that gear, but as the gears get lower automatic downshifts into them can get pretty harsh.
There is a reason those of us sitting in the left front seat are referred to as “driver” and it is because we have a lot to manage when operating the coach and have to do more than just keep it in the right lane. Operating a jake or retarder is something we have to participate in to maintain the proper speed and braking effort and it includes gear selection, jake or retarder control setting and proper use of brakes.
Do you have pyrometers Harry?
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Per,, mine (5 sp. 755CR) downshifts automatically until you are almost stopped or it downshifts to first gear. It will bring it down pretty quick from 65 mph working itself down though gears.
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Glens,
It sounds like the 5-speed can be programmed to downshift just like our 6-speeds. I guess I was not confused after all!
Tradewinds Coach
Kyle Bennett (Service)
Brian Miller (Sales) -
I don’t think the downshifting has anything to do with the jake. The Tranny is an automatic and will downshift to lower gears if the speed and RPM’s are right. As Jon say you can’t make it downshift if the RPM’s are too high. As Jim said find the top speed and RPM for each gear so when the numbers match you can safely drop a gear and feel the jake working. Harry I have a Beaver also and the Jake is not impressive to me either. If you have DD dealer close you might take it to them and see if Beaver made any changes to the programing. If you are really going down hill at 95 throwing out the Anchor(jake) will be like using a piece of yarn for rope.
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Nope, no pyrometers!
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Harry are you sure? Big dial, center dash, two needles pointing at each other.
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Greg,
The 6-speed transmission can be set up to downshift to the lowest safe gear when the Jake brake is on. Ours is set to downshift to second gear–but you can choose any of the lower gears. When I turn the Jake on, it will downshift through fifth gear to fourth at 65 MPH, with pretty good braking. Without the Jake on, the downshift to fifth will happen at 55 MPH, so with the Jake on and the transmission programmed to downshift, downshifting happens much earlier, with resultant better braking. You can also manually downshift to second gear at 65 MPH, and the transmission will only downshift when it is safe to do so. From what Glens mentions, it sounds like the 5-speed can be set up the same way, but clarification of the issue would help. An Allison dealer can reprogram the transmission if desired.
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I can only add to this conversation by comparing the different characteristics of the engine braking systems on my two busses.
1) 1957 Flxible Starliner: There’s a toggle switch on the dash for the engine brake. It’s either on or off. When it’s off and I remove my foot from the accelerator pedal, it appears to freewheel. When the switch is set to on, when I remove my foot from the pedal, I can definitely feel the difference…even when removing my foot from the pedal at higher speeds. The slower the speed of the bus, the more pronounced the feel of the engine assisting in slowing down the bus. FYI, the Starliner has a Cummins ISC 8.3 litre turbo diesel and an Allison six-speed transmission with double overdrive. There has been no need to manually downshift to feel the engine braking effect.
2) 2014 Prevost X3: This has a two-stage engine brake and it’s my habit to set it to 2 when I’m rolling and keep it on while driving. When I remove my foot from the accelerator, the engine braking is much more subtle than the Flxible and the braking effect is felt more the slower the bus goes. It has the Volvo engine and of course, the Allison transmission. Like Harry, my eyes are up and not looking at the transmission when driving. The exception is when navigating a mountain range and, on occasion, have down- or up-shifted.
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Hi Andy, when I was talking about looking at the transmission buttons I meant when I was the mountains with the need to downshift.
And im wrong about the Pyro gauges, I do have them but they don’t work. At least they didn’t when I got the coach. I’ll let you know Tuesday if they’re working now?
Harry
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They (pyro’s) are handy to let you know what’s going on with engine for sure. Watch them rise and see temps on heat gauge follow shortly. Mine stay about the same on both banks. Seems like when I had the issue with blower seals one side was higher than other. Got mine into shop when I first noticed the problem (Oil blowing out check valve/vent tubes) and after they are back to normal. Both staying the same or close. Mine has never went above 900 degrees, then again there are not many tall hills around Central Texas.
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Harry I don’t know how to tell you to check the wiring for the Pyro’s with a multimeter but I would first follow the wiring diagrams in the drivers electrical bay and engine bay electrical and see if anything is disconnected.
Greg
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Andy,
Does your Starliner have a Jake brake or an exhaust brake? I thought the Cummins ISC only came with an exhaust brake.
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If the pyros are working they will rise as the coach is pulling under a load and drop when you take your foot off the gas. There should be one threaded into each of the exhaust manifolds. If they don’t work they are easy to replace.
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Per, I believe the Starliner has an exhaust brake.
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