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Allison Transmission question

Yahoo Message Number: 273
I had a 2003 GMC 2500HD, 8.1, Allison 1000. When in Tow/Haul mode
going downhill, a touch of the brakes caused the transmission to down
shift. A little harder touch of the brakes caused another down
shift. The Allison 1000 on my Kodiak 5500 doesn't seem to do this -
should it?? Or is it set up significantly different. I do know it
doesn't have a Tow/Haul mode, but I assumed that was because it is
ALWAYS in that mode.

Re: Allison Transmission question

Reply #1 –
Yahoo Message Number: 274
Timely. I've just been pondering my C5500 as well. We have (or are supposed to have) the 6 speed. The shift indicator says, I think 1-2-3-D-N-R-P. I don't want to turn the ignition key on to show what I have got since I will have to pull in the slides as the designers chose to have the jacks retract when the ignition is turned on. This pattern seems to indicate a 5 speed not 6 speed - but the manuals sure are not clear on this at all.

I have a Switch to turn off the overdrive, and I assume that means it won't go beyond 4th if I do that. I find the discussion of "ranges" in the Allison manual very confusing.

I too did not find the transmission shifting down on its own when braking on downhill runs in Tennessee last week.

My Kodiak manual is not very helpful as it seems to cover the waterfront with a wide range of different transmissions, transfer cases, etc.

One thing it did talk about was tow-haul mode.

If someone can enlighten me (us) on what I should have for the 6 speed and how it is to work I'd be more than ecstatic.

Don

Kent Savage wrote:

Re: Allison Transmission question

Reply #2 –
Yahoo Message Number: 275
My C5500 is a 2004 chassis so I KNOW it is a 5 speed Allison 1000.
I also have the dash switch to turn the OD off, but that still
doesn't do what the 2003 2500HD did on down hill slow downs.

, "Donald A. Leslie"
wrote:
Quote
Timely. I've just been pondering my C5500 as well. We have (or
are supposed to have) the 6 speed. The shift indicator says, I think
1-2-3-D-N-R-P. I don't want to turn the ignition key on to show
what I

Quote
have got since I will have to pull in the slides as the designers
chose to have the jacks retract when the ignition is turned on. This
pattern seems to indicate a 5 speed not 6 speed - but the manuals sure are
not clear on this at all.

I have a Switch to turn off the overdrive, and I assume that means
it won't go beyond 4th if I do that. I find the discussion
of "ranges" in

Quote
the Allison manual very confusing.

I too did not find the transmission shifting down on its own when
braking on downhill runs in Tennessee last week.

My Kodiak manual is not very helpful as it seems to cover the
waterfront with a wide range of different transmissions, transfer cases, etc.

One thing it did talk about was tow-haul mode.

If someone can enlighten me (us) on what I should have for the 6
speed and how it is to work I'd be more than ecstatic.

Don

Kent Savage wrote:

I had a 2003 GMC 2500HD, 8.1, Allison 1000. When in Tow/Haul mode
going downhill, a touch of the brakes caused the transmission to
down shift. A little harder touch of the brakes caused another down
shift. The Allison 1000 on my Kodiak 5500 doesn't seem to do
this -

Quote
should it?? Or is it set up significantly different. I do know it
doesn't have a Tow/Haul mode, but I assumed that was because it
is

Re: Allison Transmission question

Reply #3 –
Yahoo Message Number: 276
, "Kent Savage"
wrote:
Quote
I had a 2003 GMC 2500HD, 8.1, Allison 1000. When in Tow/Haul mode
going downhill, a touch of the brakes caused the transmission to down
shift. A little harder touch of the brakes caused another down
shift. The Allison 1000 on my Kodiak 5500 doesn't seem to do this -
should it?? Or is it set up significantly different. I do know it
doesn't have a Tow/Haul mode, but I assumed that was because it is
ALWAYS in that mode.

There are many, many versions of the Allison 1000 transmission. The
pickups have been coming with the Tow/Haul mode and hill/grade braking
features. To the best of my knowledge, the Kodiaks do not have these
features.

You can look over your driver's sun visor and you may find your RPO
codes which will tell you the various components your MH has. For
2006 (I don't have the guide for earlier years), there are three RPOs
for Allison 1000 five speed transmissions, the standard for the MH
C5500 chassis is M74.

This link is for the 2006 GM Online Order/Reference Guide which shows
the RPO codes.

Hope this helps.

Paul

Re: Allison Transmission question

Reply #4 –
Yahoo Message Number: 277
, "Kent Savage"
wrote:
Quote
I had a 2003 GMC 2500HD, 8.1, Allison 1000. When in Tow/Haul mode
going downhill, a touch of the brakes caused the transmission to down
shift. A little harder touch of the brakes caused another down
shift. The Allison 1000 on my Kodiak 5500 doesn't seem to do this -
should it?? Or is it set up significantly different. I do know it
doesn't have a Tow/Haul mode, but I assumed that was because it is
ALWAYS in that mode.

There are many, many versions of the Allison 1000 transmission. The
pickups have been coming with the Tow/Haul mode and hill/grade braking
features. To the best of my knowledge, the Kodiaks do not have these
features.

You can look over your driver's sun visor and you may find your RPO
codes which will tell you the various components your MH has. For
2006 (I don't have the guide for earlier years), there are three RPOs
for Allison 1000 five speed transmissions, the standard for the MH
C5500 chassis is M74.

This link is for the 2006 GM Online Order/Reference Guide which shows
the RPO codes.

http://eogld.ecomm.gm.com/NASApp/mediumduty/proddesc.jsp?year=2006&brandID=1&line=95&modelID=1189&package=1277&series=1

Hope this helps.

Paul

Re: Allison Transmission question

Reply #5 –
Yahoo Message Number: 278
, "Kent Savage"
wrote:
Quote
I had a 2003 GMC 2500HD, 8.1, Allison 1000. When in Tow/Haul mode
going downhill, a touch of the brakes caused the transmission to down
shift. A little harder touch of the brakes caused another down
shift. The Allison 1000 on my Kodiak 5500 doesn't seem to do this -
should it?? Or is it set up significantly different. I do know it
doesn't have a Tow/Haul mode, but I assumed that was because it is
ALWAYS in that mode.

There are many, many versions of the Allison 1000 transmission. The
pickups have been coming with the Tow/Haul mode and hill/grade braking
features. To the best of my knowledge, the Kodiaks do not have these
features.

You can look over your driver's sun visor and you may find your RPO
codes which will tell you the various components your MH has. For
2006 (I don't have the guide for earlier years), there are three RPOs
for Allison 1000 five speed transmissions, the standard for the MH
C5500 chassis is M74.

This link is for the 2006 GM Online Order/Reference Guide which shows
the RPO codes.

http://eogld.ecomm.gm.com/NASApp/mediumduty/proddesc.jsp?year=2006&brandID=1&line=95&modelID=1189&package=1277&series=1

Hope this helps.

Paul

Re: Allison Transmission question

Reply #6 –
Yahoo Message Number: 279
, "Donald A. Leslie"
wrote:
Quote
Timely. I've just been pondering my C5500 as well. We have (or are
supposed to have) the 6 speed. The shift indicator says, I think
1-2-3-D-N-R-P. I don't want to turn the ignition key on to show what I
have got since I will have to pull in the slides as the designers
chose to have the jacks retract when the ignition is turned on. This
pattern seems to indicate a 5 speed not 6 speed - but the manuals sure are not
clear on this at all.

I have a Switch to turn off the overdrive, and I assume that means it
won't go beyond 4th if I do that. I find the discussion of
"ranges" in

Quote
the Allison manual very confusing.

"the designers chose to have the jacks retract when the ignition is
turned on."

Don,

I have the same problems with the Seneca's levers and I don't think it
is correct. In fact, IMO I believe this is a dangerous situation.
Our motorhome went into the shop today for a fix to this (and other)
issues. I'll advise if there is a "cure" for this leveling problem.

Also, see my post regarding transmissions and RPO codes.

Paul
Quote
I too did not find the transmission shifting down on its own when
braking on downhill runs in Tennessee last week.

My Kodiak manual is not very helpful as it seems to cover the
waterfront

Re: Allison Transmission question

Reply #7 –
Yahoo Message Number: 301
, "kemper_mm"
wrote:
Quote
, "Kent Savage"
wrote:

I had a 2003 GMC 2500HD, 8.1, Allison 1000. When in Tow/Haul
mode going downhill, a touch of the brakes caused the transmission to
down shift. A little harder touch of the brakes caused another down
shift. The Allison 1000 on my Kodiak 5500 doesn't seem to do
this -

Quote
should it?? Or is it set up significantly different. I do know
it doesn't have a Tow/Haul mode, but I assumed that was because it
is ALWAYS in that mode.

There are many, many versions of the Allison 1000 transmission. The
pickups have been coming with the Tow/Haul mode and hill/grade
braking features. To the best of my knowledge, the Kodiaks do not have
these features.

You can look over your driver's sun visor and you may find your RPO
codes which will tell you the various components your MH has. For
2006 (I don't have the guide for earlier years), there are three
RPOs for Allison 1000 five speed transmissions, the standard for the MH
C5500 chassis is M74.

This link is for the 2006 GM Online Order/Reference Guide which
shows the RPO codes.

Hope this helps.

Paul

From what I was able to find out a few months ago, GM started putting
the 6 speed in the MH chassis in August 0f 2006. The RPO code is
MTR. My 07 Greyhawk was made in December of 06, but the chassis was
made in October of 06. It does have the 6 speed and the RPO code of
MTR. Can't help you with the braking part, I haven't been in any
hills or mountains so far.

Mike

Re: Allison Transmission question

Reply #8 –
Yahoo Message Number: 302
What I'd like to have is something that indicates what gear I'm in. Our Journey had an info screen that provided that on one of its options but the screen was so bad you could barely read it.

I still haven't turned on ignition (since it is parked and slides out and jacks down) to check the shift pattern - Mike, is it 1-2-3-D-N-R-P?

If I want to downshift and go to 3 just what does that do to gear range. From the manual I just don't find it that clear. (pages 18 and 19 of the Allison Manual).

Don

smokie39157 wrote:

Re: Allison Transmission question

Reply #9 –
Yahoo Message Number: 303
Attachments :

    It is actually what you would call a "double" overdrive from what I can gather. This gives it 6 speeds. I have enclosed an attachment I found on the web several months ago. I can't remember where I found it . It is a "xls" spread sheet file. It tell you a good bit about the shift indicators also.

    Mike

    From: KodiakChassisClassC@yahoogroups.com [mailto:KodiakChassisClassC@yahoogroups.com] On Behalf Of Donald A. Leslie
    Sent: Thursday, November 15, 2007 7:08 AM
    To: KodiakChassisClassC@yahoogroups.com
    Subject: Re: [KodiakChassisClassC] Re: Allison Transmission question

    What I'd like to have is something that indicates what gear I'm in. Our Journey had an info screen that provided that on one of its options but the screen was so bad you could barely read it.

    I still haven't turned on ignition (since it is parked and slides out and jacks down) to check the shift pattern - Mike, is it 1-2-3-D-N-R- P?

    If I want to downshift and go to 3 just what does that do to gear range. From the manual I just don't find it that clear. (pages 18 and 19 of the Allison Manual).

    Don

    smokie39157 wrote:

    Re: Allison Transmission question

    Reply #10 –
    Yahoo Message Number: 304
    We were kind of keen to get the 6 speed and Jayco confirmed to your dealer that we'd have the 6th gear provides the second OD which is .61 - which helps on fuel economy and keeps revs down to about 1890 at 60 MPH. The spreadsheet shows the 7 pattern shift quad that doesn't tie to mine but I think 1-2-D-OD is the same as 1-2-3-D. Sure wish they'd give some examples though.

    Don

    Mike wrote:

    Re: Allison Transmission question

    Reply #11 –
    Yahoo Message Number: 305
    On my Greyhawk the transmission selector has the following:

    1 2 3 D N R P

    Now, the last time I had mine out driving it (last weekend) I
    intended to stop and play with the shifter in each gear to see how it
    reacts...but I forgot to try it. I don't know if it stays in "1" if
    you put the selector in "1" or if it will automatically upshift to 2
    or 3. I don't know if you put in "3" if it will try to start off in
    3 or if it will use 1 and 2 and then stay in 3 until you move it
    to "D". I guess "D" includes 4th gear and the over drives. Of
    course you can use the overdrive "off" switch to turn off the
    overdrive. I don't know if the overdrive "off" stops just 6th gear
    or 5th and 6th.

    Mike

    , "Donald A. Leslie"
    wrote:
    Quote
    We were kind of keen to get the 6 speed and Jayco confirmed to your
    dealer that we'd have the 6th gear provides the second OD which
    is .61 -

    Quote
    which helps on fuel economy and keeps revs down to about 1890 at 60
    MPH. The spreadsheet shows the 7 pattern shift quad that doesn't
    tie to

    Quote
    mine but I think 1-2-D-OD is the same as 1-2-3-D. Sure wish
    they'd

    Quote
    give some examples though.

    Don

    Mike wrote:

    It is actually what you would call a "double" overdrive from what
    I can gather. This gives it 6 speeds. I have enclosed an
    attachment I

    Quote
    found on the web several months ago. I can't remember where I
    found it . It is a "xls" spread sheet file. It tell you a good bit
    about the shift indicators also.

    Mike

    ------

    Quote
    From: KodiakChassisClassC@yahoogroups.com
    [mailto:KodiakChassisClassC@yahoogroups.com] On Behalf Of Donald
    A. Leslie

    Quote
    Sent: Thursday, November 15, 2007 7:08 AM
    To: KodiakChassisClassC@yahoogroups.com
    Subject: Re: [KodiakChassisClassC] Re: Allison Transmission
    question
    What I'd like to have is something that indicates what gear I'm
    in.

    Quote
    Our Journey had an info screen that provided that on one of its
    options but the screen was so bad you could barely read it.

    I still haven't turned on ignition (since it is parked and slides
    out and jacks down) to check the shift pattern - Mike, is it 1-2-3-D-
    N-R-P?
    Quote
    If I want to downshift and go to 3 just what does that do to gear
    range. From the manual I just don't find it that clear. (pages
    18 and

    Quote
    19 of the Allison Manual).

    Don

    smokie39157 wrote:

    From what I was able to find out a few months ago, GM started
    putting the 6 speed in the MH chassis in August 0f 2006. The RPO code is
    MTR. My 07 Greyhawk was made in December of 06, but the chassis
    was made in October of 06. It does have the 6 speed and the RPO code
    of

    Re: Allison Transmission question

    Reply #12 –
    Yahoo Message Number: 306
    A lot has to do with rear axle ratio and tire size what RPM your
    engine will run in OD. MY rear end ratio is 4.44. Here is a link to
    rear axle code to all GM product line. Medium duty will start with 0.
    Mine is a 036.
    http://www.vibratesoftware.com/html_help/html/GM/gm_drive_axles.htm#Numerical
    Here is another link to gear ratios for many Allison transmissions.
    http://www.vibratesoftware.com/html_help/html/GM/gm_transmissions.htm#6spdatrn
    You will also have to check tire size/circumference.
    My MH is doing 1875 RPM's in 5th gear at 60mph.

    Re: Allison Transmission question

    Reply #13 –
    Yahoo Message Number: 307
    Ron, as I recall you have a Duramax and I would think the characteristics would be a bit different. You are getting the same revs in 5th that I get in 6th and that is, no doubt, due to the diesel. Our Cummins in the Ambassador turned around 1575 at 60 MPH with the Allison 3000 MH.

    I wish the ScanGauge indicated the gear the vehicle is in.

    Mike, your 1-2-3-D is what I recall seeing on mine, and from the Allison manual it would seem that 1 means it sticks in first, 2 means it would start in first and then shift to 2nd and no further, and 3 would start in first and go up to 3rd, and D goes all the way to 6th unless OD is off - and then one would think it only goes to 4th - but who knows for sure.

    Don

    Re: Allison Transmission question

    Reply #14 –
    Yahoo Message Number: 310
    I took delivery of our Jayco Greyhawk 32SS on April 2007 in Buffallo NY. We hit that damned nor easter all the way to Florida. Going through the smoky mountains I kept the cruise control on all the way and never touched the breaks untill we would decide to pull off the road for something. Weather was so bad we couln't even see the mountains. I was very impressed with the way it handle coming down the sharp inclines..Handled very well. I was impressed, but them again I had no tow vehicle.

    Brent Bautel

    smokie39157 wrote:

    Re: Allison Transmission question

    Reply #15 –
    Yahoo Message Number: 311
    Don
    Which engine has nothing to do with RPM's at a given speed. That is
    controlled by transmission gear, rear axle ratio and tire size. If the
    engine can pull the load at a given RPM would depend on engine.

    Re: Allison Transmission question

    Reply #16 –
    Yahoo Message Number: 312
    I agree but you've got the torque in a diesel that allows a lower rear end than a gasser and thus with the same gearbox and ratios, lower revs. So your 5 speed turns about what my 6 speed does. My rear axle ration is 5.13:1 based on the GM specs. What is yours? If it is the same, then the question is how do you get in 5th with .71, what I get in 6th with .61?

    Don

    Re: Allison Transmission question

    Reply #17 –
    Yahoo Message Number: 313
    My rear end ratio is 4.44 with 225/70 19.5 tires. Thats how I get a
    similar engine rpm. I think you will find that the 5 speed gas models
    have the same rear ratio as I have with the same tires. The six speeds
    and added gear and rear end ratio allows for more RPM's in the lower
    gears at the same speed. Better way to put it is 6 gears spread over
    the speed range means closer gears and less power loss when down
    shifting to a lower gear.
    I do not know if 6 speed is needed in the Duramax. But sure will help
    a gas model.
    I posted the links to help others that want to know there ratio can
    find out what they have.