Community Forums

yeloduster · 01-02-2021, 06:49 PM

Quote:

Originally Posted by edgray

I suggest you call URVP and ask for either Jon Brazel or Alan Sanders. They can answer exactly what comes with what they sell.
I'm guessing the "Larry brake" is yeloduster himself, but I don't know how much he costs

Larry Brake is yeloduster himself! He can be really cheap if we are going somewhere interesting!

AKIQPilot · 01-03-2021, 06:30 AM

Quote:

Originally Posted by Flyer15015

Sorry to bump in here, but I am about to become a Workhorse owner.
Coming from a diesel class "C" to an '04 Pace Arrow 37c, I'm starting to read all I can, to see what must be done on this "bone stock" W-22 unit.

So, my question is, if I get the Ultra RV ECM and TCM, will it have the grade brake as a component in the TCM ? Or, do I need to purchase that separately from Ultra ?
Also, what is a "Larry" Tx brake ? Is it compatible with Ultra's TCM module ?
Just a newbie looking for guidance. Thanks in advance.......

Mike in Colorado
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Hey Mike. I have the Ultra RV ECM tune and the TCM tune on our Sun Cruiser. The TCM tune does not come with a grade brake feature. The TCM tune allows the transmission to shift into 5th gear up to 10mph lower than the stock transmission tune depending on throttle position, load, etc. This is especially handy if you are on roads with a 45 or 50 mph speed limit. You can get rolling and up to the posted speed limit then back off on the throttle and the transmission will gently slip into overdrive and you will be poking along at 1600rpm at 50mph.

Without the TCM tune you have to exceed 55mph to get the transmission to shift into 5th.

The TCM tune will also hold 5th gear a little longer and prevent downshift on slight grades. Say you are rolling along at 60mph @ approximately 2000rpm. A slight hill approaches. You can add a little throttle to maintain your speed. The transmission will sense the slight load increase but not automatically kick down into 4th. If you start to lose speed and give it a little more throttle the transmission will shift down to 4th to get the motor back up toward peak torque. This feature of the URVP Trans Tune helps to reduce or eliminate the transmission hunting and jumping between 4th and 5th at slight load changes when traveling at highway speeds.

The TCM tune is a great investment for the 5 speed. Everything about the changes are positive.

The Larry Brake is just manually shifting the transmission yourself. Toggling the overdrive switch on or off is a great way to imitate the grade brake without touching the brake pedal. You are effectively manually selecting 4th and 5th gears with the switch. The selection is immediate and never jumps down 2 gears or revs the motor over about 600rpm more than it was. Note: on the 6 speed Allison you can use the overdrive switch to select between 4th, 5th and 6th. If you need to get down to 3rd gear or lower for engine braking you just use the gear shift lever.

With the grade brake engaged, if you begin descending at say 55mph @ 1900 rpm as soon as you apply the brake the transmission will jump down 2 or sometimes 3 gears and rev the engine up to 3500-4000rpm or even more. This is a very abrupt change in engine RPM. Obviously the old Big Block is designed to handle this abrupt change but there is no way its good to spin the motor that fast if you dont have to. Ive seen my grade brake jump the engine rpm from 2200rpm to 4200rpm in under 1 second. I prefer to be much easier on the motor than what the grade brake is.

By manually down shifting you can limit the rpm changes to 500 or less for a much smoother transition between each down shift.

AKIQPilot · 01-03-2021, 06:44 AM

The other very annoying feature of the grade brake is as soon as you touch the gas pedal the grade brake is disengaged and the transmission immediately shifts right to either 5th or 6th gear and you begin picking up speed. As soon as you touch the brake again the grade brake kicks in again and the transmission down shifts a couple of gears and the engine revs wildly trying to get the coach slowed down.

This may not seem like a big deal but not every downhill grade is linear from top to bottom. Sometimes you may need to touch the throttle slightly when descending, like when the hill changes from an 8% decline to a 4% decline for a short period of time in the middle of the decline. As soon as you touch the throttle the grade brake immediately disengages and you begin picking up speed. Seconds later you touch the brake and the transmission drops a couple of gears and the motor revs way out of my comfort zone.

Lots of people like the grade brake feature on the Workhorse 8.1/Allison combo. I do not because of how slow and unnecessary it reacts to downshifting the transmission.

CamJam1 · 01-03-2021, 06:20 PM

Quote:

Originally Posted by Flyer15015

Sorry to bump in here, but I am about to become a Workhorse owner.
Coming from a diesel class "C" to an '04 Pace Arrow 37c, I'm starting to read all I can, to see what must be done on this "bone stock" W-22 unit.

So, my question is, if I get the Ultra RV ECM and TCM, will it have the grade brake as a component in the TCM ? Or, do I need to purchase that separately from Ultra ?
Also, what is a "Larry" Tx brake ? Is it compatible with Ultra's TCM module ?
Just a newbie looking for guidance. Thanks in advance.......

Mike in Colorado

I'd worry about the suspension first. Front and rear trac bars and either a caster adjustment or a steering stabilizer will make a world of difference. If you really wanted to go all out add sway bars and Sumo Springs.

Hopefully your rig will come to you with at least some of these mods done by a previous owner.