How to hold 3rd going down hill??

[32vSouthwind]

I have the Allison 1000 with the 8.1 Workhorse. The gear selector allows a choice of 1 2 3 or D. However when you select "3" the trans will go up to 4th and that is not enough to hold back the coach.
Am i missing something?

[RickO]

Hi and welcome to the forum!

I'm not familiar with the Allison 1000 but on my 3000 I know it will not allow the engine to over rev and will upshift to prevent it. I'm sure one of our members familiar with your tranny will chime in soon.

Good luck...

rick

[mfire1339]

Welcome 32V,

I have a 2004 allison 1000 and it will not hold my speed going down Cajon pass in third gear unless I brake very hard a couple times to get my speed down to 55 or so. If I didn't slow it with the brakes it would rev engine way too high for my liking and shift on it's own to 4th gear. Other wise you may just need linkage adjustment to really be in 3rd.

Mike

[az bound]

If the RPMs are allowed to approach 5000 it will upshift automatically to keep from damaging the engine. It really needs your assistance to control speed on downgrades. Step on the brake rather hard to scrubb of speed and let the engine/tranny do its job. On long decents it may need to be repeated several times. Just remember not to ride the brakes for long periods.
There is video and instructions at www.workhorse.com I believe is titled mountain driving that explains it much better than I could.

[edgray]

This link: Brake Recall Resource Center
takes you to the page azbound mentioned above. On the right side is a "library" of articles with at least two on the subject of this thread. Lots of other good info there, too.

[az bound]

Thanks edgray. I believe there is an aftermarket grade brake that can be added to the allison 1000. DriVer would be the best source for that information. I believe the addition is in the $1,500 range and well worth it.

[alvinc]

Quote:

Originally Posted by 32vSouthwind I have the Allison 1000 with the 8.1 Workhorse. The gear selector allows a choice of 1 2 3 or D. However when you select "3" the trans will go up to 4th and that is not enough to hold back the coach. Am i missing something?

From an earlier post of mine.

My Allison was programmed with the incorrect shift pattern. I had a little difficulty getting, Fleetwood and Allison to believe me, but I took it to the Allison service center and they test drove it, and still didn't believe it; thought that was how it should be. They were kind enough to call the internal Allison help desk, and voila, they had heard of it. The service center downloaded and installed the correct firmware.

DETAILS:

Correct shift pattern with overdrive panel switch:
D -3-2-1 shifter corresponds to
(5,4)-3-2-1 gears

Alternate pattern if no overdrive panel switch is available:
D- 3 -2-1 shifter corresponds to
5-(4,3)-2-1 gears

Note that this allows the driver to shift to "3" to lock out overdrive without having a panel switch. I presume that this if for panel trucks and non-RV types of applications.

There are two ways to notice the difference. One is that there is shifting taking place when the gear shift is in 3rd. The second, and best, is on a slight downhill with shifter in D, overdrive on. When you turn off the overdrive, there should be a downshift (both will do this), then when you move the shifter to "3" there should be another downshift (keeping within RPM limits of course). If you cannot effect a downshift by going from "D" to "3" you may have the wrong transmission programming.

[32vSouthwind]

Thanks for the response, I hope Allison agrees with Alvinc, it seems a shame to pay $1000 to install a grade brake to have the ability to select the gear needed.

[alvinc]

Quote:

Originally Posted by 32vSouthwind Thanks for the response, I hope Allison agrees with Alvinc, it seems a shame to pay $1000 to install a grade brake to have the ability to select the gear needed.

Give me a ring if they want to argue about it..... I am willing to talk to them.

[edgray]

Quote:

Originally Posted by 32vSouthwind Thanks for the response, I hope Allison agrees with Alvinc, it seems a shame to pay $1000 to install a grade brake to have the ability to select the gear needed.

32vSouthwind: If yours does not already have the Allison "grade brake" feature, you can buy an aftermarket "grade brake" from Brazel's of Centrailia, WA.

However, you need to understand that a "grade brake" is not a brake at all. It is simply a convenience feature which sends a downshift command to the tranny when you step on the brake pedal, AND when several other conditions are being met. One is "negative slip", which means you are coasting downhill, and the other is that the engine RPMs are low enough to allow the DS without over-reving the engine.

Even if you use the "grade brake" feature repeatedlyto DS to each lower gear, if your downhill speed increases to the point of dangerously high RPMs, then the ECM and TCM will decide to upshift to save the engine, and you'll begin gaining speed. To prevent an upshift under these conditions you will need to agressively use the service brakes to cut your speed and maintain the lower gear.

Without a "grade brake" feature you can accomplish the exact same results by simply pulling the shift lever into whatever lower gear is appropriate. It is always advisable to DS at the top of the grade, BEFORE you attain excessive speed and use the brakes sparingly, but you should not expect the engine to hold back gravity all by itself on really steep declines.
Ed

[32vSouthwind]

My goal is to be able to select/use 3rd to help slow the coach going down hill and that is not possible now.
I will contact Allison and discuss the fix, thanks to all for the help.
Chris

[DAN L]

Quote:

Originally Posted by 32vSouthwind My goal is to be able to select/use 3rd to help slow the coach going down hill and that is not possible now. I will contact Allison and discuss the fix, thanks to all for the help. Chris

brazels in centralia, wa. changed the programming on my 5 sp ally 1000 to shift into od at 48 mph, at about 1600 rpm under light load during the summer of 2010. this works well for me. it shifted at 55 mph originally. i did not want the grade brake installed.
brazels installed an update on my 5sp ally 1000 pursuant to service bulletin 70301t in may, 2011. the purpose was to keep the tranny from rapidly shifting out of od to 4th then 3rd gears under load. it works better now.
i use 2nd gear at 4000-4400 rpm when descending 5-6% grades on interstate highways. 3rd gear doesn't get the job done. i still do not want the grade brake installed.