Allison performance tune

[eandy]

Having made 2 trips in the past 60 days and having 2 more in the next 30 over exactly the same route in moving to Abq driving hwy 58-40, I'm getting a true knowlege of effects of UPT.

To make my point I have to use the operation of the minivan as a comparison. When in cruise it drops to a lower gear with a 1 mph drop in speed while the Allison slides about 3 mph before downshifting. I really like that about the Allison. In either vehicle the mpg is obviously affected. Again, being a conservative driver, I prefer the MH not exceed 4k rpm just for the wear and tear.

The minivan got right at 24 mpg all hwy on a return trip keeping cruise on. On the last return dropping out of cruise and going easy but fairly well keeping speed going uphill using gas pedal it did 27.25 mpg.

So the issue with the Allison is not with doing the really bad mtns, but with the short uphills where it drops to lower gear with only 20-40 yards to crest of incline. I can drop out of cruise on the same inclines and maintain speed or only drop 1-2 mph before cresting.

If the minivan mpg is that radically affected so must the coach be. I'll head off many responses by stating the rig is maxed on wt. The lighter rigs probably don't experience the same thing but most 36' and larger probably do.

I'm wondering if an Allison shop, if it's out of Mike B's scope, can program the tranny computer to deal with that. What I loose in speed going up I make up for going down.

The strange thing too is that it downshifts on some inclines and not on others that look and feel about the same.

[eandy]

Having made 2 trips in the past 60 days and having 2 more in the next 30 over exactly the same route in moving to Abq driving hwy 58-40, I'm getting a true knowlege of effects of UPT.

To make my point I have to use the operation of the minivan as a comparison. When in cruise it drops to a lower gear with a 1 mph drop in speed while the Allison slides about 3 mph before downshifting. I really like that about the Allison. In either vehicle the mpg is obviously affected. Again, being a conservative driver, I prefer the MH not exceed 4k rpm just for the wear and tear.

The minivan got right at 24 mpg all hwy on a return trip keeping cruise on. On the last return dropping out of cruise and going easy but fairly well keeping speed going uphill using gas pedal it did 27.25 mpg.

So the issue with the Allison is not with doing the really bad mtns, but with the short uphills where it drops to lower gear with only 20-40 yards to crest of incline. I can drop out of cruise on the same inclines and maintain speed or only drop 1-2 mph before cresting.

If the minivan mpg is that radically affected so must the coach be. I'll head off many responses by stating the rig is maxed on wt. The lighter rigs probably don't experience the same thing but most 36' and larger probably do.

I'm wondering if an Allison shop, if it's out of Mike B's scope, can program the tranny computer to deal with that. What I loose in speed going up I make up for going down.

The strange thing too is that it downshifts on some inclines and not on others that look and feel about the same.

[Tenn.Vol.]

Eandy, thats the same problem I have on my 02, WH. I can not run in CC because with
the slighest incline or when it drops 1 MPH it drops out of OD. Because of this I
almost never run in CC. The Allison need to be reprogramed to allow it to drop 3 to
5 MPH before it drops a gear.

The transmission was reflashed at the Allison Detroit SC in Seattle a couple of yrs.
ago. When I complained that some time it would drop 2 gears when it came out of OD.

What I usually do when in the mountains, (upstate NY) I go down 70 to 80MPH
and up 50 to 60 MPH. Had the ECM programmed and the speed limiter was either
removed or bumped up above 80MPH, I have not found it yet, the limit that is!
As my toad has been my limiter at this time. TENN.VOL.

[Full-Timers]

HUH, I thought the reprogramming that Tenn.Vol. had done made the Allison less aggressive. I haven't had my 2002 Allison reprogrammed yet and hoped it would also solve the 1 mph downshift.

[dieselclacker]

Maybe the problem is in the cruise control instead of the Allison. I seldom use the cruise control for the same reasons as Tenn Vol. Mine also will drop down two gears on some hills, and also when the resume button is pushed when you are traveling at too low a speed. Wonder if the cruise control amplifier can be modified or adjusted to make it a little less sensative?

Dieselclacker

[dieselclacker]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by eandy:
Having made 2 trips in the past 60 days and having 2 more in the next 30 over exactly the same route in moving to Abq driving hwy 58-40, I'm getting a true knowlege of effects of UPT.

To make my point I have to use the operation of the minivan as a comparison. When in cruise it drops to a lower gear with a 1 mph drop in speed while the Allison slides about 3 mph before downshifting. I really like that about the Allison. In either vehicle the mpg is obviously affected. Again, being a conservative driver, I prefer the MH not exceed 4k rpm just for the wear and tear.

The minivan got right at 24 mpg all hwy on a return trip keeping cruise on. On the last return dropping out of cruise and going easy but fairly well keeping speed going uphill using gas pedal it did 27.25 mpg.

So the issue with the Allison is not with doing the really bad mtns, but with the short uphills where it drops to lower gear with only 20-40 yards to crest of incline. I can drop out of cruise on the same inclines and maintain speed or only drop 1-2 mph before cresting.

If the minivan mpg is that radically affected so must the coach be. I'll head off many responses by stating the rig is maxed on wt. The lighter rigs probably don't experience the same thing but most 36' and larger probably do.

I'm wondering if an Allison shop, if it's out of Mike B's scope, can program the tranny computer to deal with that. What I loose in speed going up I make up for going down.

The strange thing too is that it downshifts on some inclines and not on others that look and feel about the same. </div></BLOCKQUOTE>

Its been my expierience in traveling Interstate 40 many many times, the the miles per gallon is always better going from east to west. Don't know exactly why, continental devide maybe.

Dieselclacker

[Full-Timers]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by dieselclacker:
Maybe the problem is in the cruise control instead of the Allison. I seldom use the cruise control for the same reasons as Tenn Vol. Mine also will drop down two gears on some hills, and also when the resume button is pushed when you are traveling at too low a speed. Wonder if the cruise control amplifier can be modified or adjusted to make it a little less sensative?

Dieselclacker </div></BLOCKQUOTE>Allison does have a Technical Service Bulletin on the double downshift problem. They will reprogram the TCM.

[tderonne]

Just FYI. The shift schedule is different when the cruise is on. At least it can be, depends exactly how it's calibrated.

[LeeB]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Allison does have a Technical Service Bulletin on the double downshift problem. They will reprogram the TCM </div></BLOCKQUOTE>

As Fulltimer stated... I had my TCM reflashed and it worked wonders... NO more Downshifting on slight inclines... I want to use CC even if it cost me a little... I love having me feet free IMO

[eandy]

Good input. I'll get to an Allison shop for reprog when I can. Suspect this is the reason some of us are not getting as good results from UPT as others. Thanks

[Full-Timers]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by LeeB:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Allison does have a Technical Service Bulletin on the double downshift problem. They will reprogram the TCM </div></BLOCKQUOTE>

As Fulltimer stated... I had my TCM reflashed and it worked wonders... NO more Downshifting on slight inclines... I want to use CC even if it cost me a little... I love having me feet free IMO </div></BLOCKQUOTE>You just like dancing to that XM Radio while going down the road.

[LeeB]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Full-Timers:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by LeeB:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Allison does have a Technical Service Bulletin on the double downshift problem. They will reprogram the TCM </div></BLOCKQUOTE>

As Fulltimer stated... I had my TCM reflashed and it worked wonders... NO more Downshifting on slight inclines... I want to use CC even if it cost me a little... I love having me feet free IMO </div></BLOCKQUOTE>You just like dancing to that XM Radio while going down the road. </div></BLOCKQUOTE>
Ha ha ha All that music was coming from my laptop... Besides I dance about as much as you do LOL

[RetiredSKP]

I am having the same problem with shifting. I talked to Randy Cervenka at Diesel Power Supply Co. in Waco, Texas. He told me that there is a "Service Information Letter" by Allison to address the problem. It is SIL 18-1K2K-02 Rev A. I have made an appointment with him to get my transmission reprogramed. I have not been able to find a copy of the letter anywhere on the Internet. Does anyone have a copy they can share or know of a site where one can get a copy? Thank you for your replies.

RetiredSKP

[DriVer]

Here is the complete TSB as it appears in the Workhorse Gas Motorhome Chassis Guide.

WORKHORSE CUSTOM CHASSIS SERVICE BULLETIN

BULLETIN NO.: 70301-T November 2003

BULLETIN TYPE: Technical

SUBJECT: Transmission 5-3 downshifts

MODELS: Model 2001 and 2002 Workhorse W-Series

Motorhome chassis with Allison transmission

Some model year 01 and model year 02 W-Series Workhorse Custom Chassis
Motorhome owners have experienced rapid 5-4-3 downshifts while in cruise control.
This condition occurs with the cruise control active while driving on a slight and/or
moderate incline. If the vehicle speed decreases more than 3 mph, while in cruise
control, the engine control module will increase the speed to maintain the cruise
speed that was set. In order to maintain the cruise set the engine has to shift down
to get more power and sometimes down shift to the third gear to maintain the
demanded performance.

Starting with the 2003 model year, Workhorse Custom Chassis and Allison
Transmission have released new software for the Allison 1000-series control module
as well as 8.1L engine. This new software will reduce the aggressiveness of
transmission shifting and will prevent most downshifts to the third gear while in
cruise control mode.

New calibrations have also been made available for 2001 and 2002 models and will
correct the (above) condition if the chassis in question meets the stated criteria.
This condition affects only the 2001 and 2002 W/20 or W/22 model with the 8.1 V-
8 with the Allison LCT 1000 Transmission.

VEHICLES INVOLVED

Please check the VIN carefully before agreeing to the customer that we can apply
the new calibrations.
1. The VIN must start with 5B4MP67G... indicating a W-series model that is
equipped with the Allison Transmission.
2. It must be a 2001 or 2002 model year. 10th digit of VIN is 1 or 2.
3. The 2003 model year chassis have the new calibrations already installed in
both controllers and are NOT INVOLVED.

SERVICE PROCEDURE

This procedure should be followed whenever a Workhorse customer has a
transmission shift complaint as described earlier in this bulletin. Most customers
are not likely to have this complaint as vehicle weight and specifications are major
factors leading to the complaint.
1. 2001 model year W-Series chassis will need only to have the Allison TCM reflashed.
The customer must be directed to the nearest Allison Dealer. The
Allison Dealer will provide this service at no expense to the customer as
outlined by Allison Bulletin 18-1K-02, Rev. A
2. 2002 model year W-Series chassis will need to have BOTH the Allison TCM
and Workhorse PCM controller flashed.
"¢ The Allison TCM will need to be flashed first. The customer must be
directed to the nearest Allison dealer for this work. Allison does this
procedure by re-flashing the TCM with the Allison computer and
interface. The procedure usually takes 30-60 minutes. The Allison
Dealer will provide this service at no expense to the customer as
outlined by Allison Bulletin 18-1K-02, Rev. A
"¢ Once the Allison TCM has been done, the engine controller will need
to be flashed by an authorized Workhorse/GM Dealer who has a valid
GM Techline account (800) 828-6860. The new engine calibrations
are available on GM Techline CD # 8 (which was mailed to all
Techline approved dealers on 7-28-03).

Do NOT attempt to flash the TCM and engine controller of an MY01 vehicle with
MY02 calibrations. This will cause Diagnostic Trouble Codes to be set in the engine
controller which will force it into "limp home"� mode.

WARRANTY INFORMATION

Labor Operation No. -------------- T7003
(limited to 3 years/ 36,000 miles on 2002 model year only)
Labor Hours ---------------------- 1.0 Hours
Description ---------------------- Reprogram 2002 PCM for Bulletin
Keep in mind this is not a recall/campaign, but a calibration update for a limited
number of vehicles to satisfy customer complaints on vehicles still covered by
Workhorse warranty. This work should not be referred to as a campaign or recall.
Please make sure customers and dealers understand this clearly, as this can set the
tone for misunderstanding and negative perception.