Allison Transmission Tech Advice

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I have a 2009 Winnebago with the W22 Workhorse chassis and Allison 1000MH transmission with 3000 miles. Last week on a return trip on I26 from NC to TN there was a short period where the steep grade caused the transmission to shift to 2nd. The water temp went to 222 degrees and the RPMs were around 4000. The transmission apparently vented because my toad was lightly coated with trans fluid. I did a cold check of trans fluid level the next day and it showed to be about a half inch below the cold level mark. Is it normal for venting to occur in these conditions? The transmission had not previously leaked any fluid. Also, should I change the spin-on filter now rather than wait for the 5000 mile interval since the transmission was probably built in 2008?

        that must have been a heck of a grade!  ;D  I've seen the dipstick calibration incorrect on some workhorse's ,causing a fluid overfill and venting.  I've seen the tube itself not vented correctly causing fluid to come out of the rear vent.  I would crawl under the coach and look at the vent at the top of the rear main case and see if there is trans fluid on it.  the fluid on the toad could have been eng coolant overflow from the higher eng temp climbing the grade. 
  I would wait for the 5000 mile mark to change the filter.  the trans if built in 08' would have not been driven more than a few miles in the bare chassis. 
 
I checked the tube and I can find nowhere that it is vented.  I have read previously that some tubes should have a small hole near the top of the tube.  I can follow my tube all the way to the transmission and can find no hole.  Should there be one on a 1000-MH?

Thank you for making yourself available to the answer our questions.  I am relatively new to motorhome ownership and rely heavily on forum advice.  I appreciate your expertise.
 
I checked the tube and I can find nowhere that it is vented.  I have read previously that some tubes should have a small hole near the top of the tube.  I can follow my tube all the way to the transmission and can find no hole.  Should there be one on a 1000-MH?

Thank you for making yourself available to the answer our questions.  I am relatively new to motorhome ownership and rely heavily on forum advice.  I appreciate your expertise.

          there should be an 1/8" hole in the tube just below the stick's rubber stopper.  there is an Allison bulletin on this venting issue and if you decide to have a vent hole put into the tube then I would  have the dealer do it because the pan will need to come off from the metal drill shavings and the tube needs to be blown out and cleaned.  the bulletin says that if the fluid comes out of the main case vent in cold weather operation then make sure you have the dipstick tube vented, but I have found that this works in warm weather operation also.  while venting the tube the dealer can verify the dipstick calibration and fix it if its not right. 
 
Allisonman, what temp difference should I expect once I change to the Transynd fluid in my 99 Itasca (70K miles) with the MD3060? In reading the other forums I've read where a number of people have experienced harsh shifts after changing their fluid from the Dexron to the Transynd. Is this fairly common and is there a way to correct this?
 
Allisonman,

I have a 2005 Itasca Suncruiser 37B. It is on a W22 Chassis.I have an intermittent problem. The previous owner had the same problem and had it at a Workhorse service center (Cummins- Bridgeway, Novi Michigan) and they were not able to diagnose the problem.

The problem has occurred mostly when I start the engine in the morning and take a short ride to the gas station. When I fill the tank and leave the gas station the problem occurs. Normally when I am in cruise control running at 62MPH the RPM's are about 2200 RPM's and holding steady(unless I hit a rise in the pavement it downshifts and maintains a steady 3000 RPM's, or a steeper hill downshifting and maintaining a steady 4000 RPM's). The problem has occured 4 times this year and specifically when I use the cruise control. At 62 MPH the RPM's go to 2200-2600 and do not remain steady (The RPM needle drifts up and down). On a hill it will down shift to about 3600 RPM's and at 4500 RPM's on a steeper hill. If I pull off the road and turn off the engine (for a couple minutes) the shift RPM's go back to the normal steady 2200 RPM's when on cruise control. When I came home from the last trip we unloaded the coach and when I left to go back to the storage lot, RPM's again went off what I consider as normal when I am using the cruise control.

Anny suggestions?
 
Allisonman, what temp difference should I expect once I change to the Transynd fluid in my 99 Itasca (70K miles) with the MD3060? In reading the other forums I've read where a number of people have experienced harsh shifts after changing their fluid from the Dexron to the Transynd. Is this fairly common and is there a way to correct this?

            you probably won't see much of a temp. reduction difference when going to tranynd.  10-15 degrees maybe.  some people may get a rougher shift when switching over to transynd.  I wouldn't say a harsh shift but it may be more firm.  that is because dextron ,when as it gets hotter, has changes in viscosity and gets thinner a lot faster than transynd.  the trans computer learns(adapts) to the viscosity changes in dextron.  if you put transynd in the trans, the computer still believes dextron is in the trans and shift timing will be a little off.  you could have the "adaptive shifts" reset and the computer will learn to shift with transynd.  you could also just keep driving the vehicle and eventually it will adapt but, resetting the adaptive shifts will be much faster.  the only way to reset the adaptive shifts is to take it to the dealer.  it takes about 5 minutes to do it.  disconnecting the batteries will not clear codes or reset adaptive shifts on Allison computers.  the computer can sit disconnected from power for years and the previous codes will still be in there.
 
Allisonman,

I have a 2005 Itasca Suncruiser 37B. It is on a W22 Chassis.I have an intermittent problem. The previous owner had the same problem and had it at a Workhorse service center (Cummins- Bridgeway, Novi Michigan) and they were not able to diagnose the problem.

The problem has occurred mostly when I start the engine in the morning and take a short ride to the gas station. When I fill the tank and leave the gas station the problem occurs. Normally when I am in cruise control running at 62MPH the RPM's are about 2200 RPM's and holding steady(unless I hit a rise in the pavement it downshifts and maintains a steady 3000 RPM's, or a steeper hill downshifting and maintaining a steady 4000 RPM's). The problem has occured 4 times this year and specifically when I use the cruise control. At 62 MPH the RPM's go to 2200-2600 and do not remain steady (The RPM needle drifts up and down). On a hill it will down shift to about 3600 RPM's and at 4500 RPM's on a steeper hill. If I pull off the road and turn off the engine (for a couple minutes) the shift RPM's go back to the normal steady 2200 RPM's when on cruise control. When I came home from the last trip we unloaded the coach and when I left to go back to the storage lot, RPM's again went off what I consider as normal when I am using the cruise control.

Anny suggestions?

                  if the check trans light is not coming on when it occurs then it is probably the lockup clutch turning on and off.  does the ABS light come on when it happens?  usually if the ABS system has a problem it sends a signal to the trans TCM and the TCM commands the lockup clutch off. I have seen no ABS light on and this problem occur also.  it will not set a code in the TCM when this happens.  the ABS system is tied into the trans TCM because during hard braking situations when the ABS is pulsing the brakes on/off you don't want direct engine torque into the driveline.  when the lockup clutch shuts off you go from a direct coupling to a fluid coupling which will reduce the torque into the driveline and make it easier to stop.    the other thing that may be happening is an erratic speed sensor reading to the TCM but, this will set a code and a check trans light.
 
Hello Allisonman,  Will be brief. I have an Allison Md3000MH, Serial # 6510348767 in a Providence 38U Class A motorhome. Suddenly the downshift retarder stopped working as it should. Now when I switch on the retarder, the transmission shifts down to 2nd regardless of speed. I quickly switch the retarder off to keep the rpm's down. I do not have a fault code. There is a possibility that I may have had a code when this happened the first time, and I could have cleared it accidentally, as this is my first experience with an Allison transmission. Also the shifter is a single digit pushbutton WTEC III selector. Without the retarder switched on the transmission works flawlessly. I would like to say we as rver's appreciate you making your expertise available to us. Thanks, W61anderson









 
Hi W61anderson

Welcome to the Forum and please feel free to ask any question. Also, how about introducing yourself and describing your coach/equipment (year, engine model, etc.), maybe even a picture or two. Then, we'll also need you to continue to post the coach info whenever you post asking a technical question, hard to answer a problem without all the facts.

I expect that you don't have a retarder, I am only aware of Foretravels having them. Depending on your engine and specifications, you have either an exhaust brake or engine compression brake. Since your tranny downshifts to 2nd, I would venture to say that you have an exhaust brake.

How long have you owned your coach? Did it always downshift to cause you concern when the brake control was on? When your control is on and you take your foot off the accelerator pedal, the system will show 2 in the window and the tranny will start downshifting to achieve that gear. However, the tranny will not downshift to a gear that would cause your engine to overrev. As you slow down, the tranny will continue to downshift until it reaches 2nd. Keep an eye on the tach, it probably won't exceed 2400 rpm.

At first blush, with the info you provided, it seems that the tranny is working the way it is supposed to.
 
Allisonman:

10 months ago  I had our MH3000 series flushed and refilled at Freightliner as part of an M-3 service check at 100,000 miles. Freightliner replaced the Transynd that I have used at all service intervals for the past 90,000 miles with an Exxon equivalent.

My tranny temps have gone from running 190 degrees on a 75-80 degree day (while the engine coolant is cycling between 195-201 degrees) to now running 196 degrees with the same engine coolant temps.

My concern is this: When I pull off the interstate or slow down coming into an urban area the tranny instantly goes to 200 degrees and will be up to 206 within a couple of miles of city driving. If I start pulling a grade in 90 degree weather and down shift to 4th or 5th to keep the engine (Cat 3126E) up at 2000 RPMs the tranny goes over 200 degrees and will reach 206-208 in a couple of miles of pulling. As the tranny builds heat it takes several miles to get it to cool back down.

If the tranny gets up to those temps the engine temp will also start going higher than it used to do as the fan fights the increased temp buildup until the fan is running continuously and I have to back off another gear or two to cool things down. (Until I had the fluid changed this had never happened; engine temps always were higher than the tranny and were the controlling issue for climbing grades.

I have a side fan radiator that I cleaned last fall and looked clean. Just in case I spent a couple of hours last week with simple green making sure it was clean but it did not affect the temps. My gut feeling is there is something restricting the fluid flow through the radiator and will probably replace the filters again to make sure the new ones aren't the problem.

No codes and fluid level is staying normal.

Any other suggestions?
 
Jeff,, I had just the opposite results when changing to "Torque Drive" the Amsoil equivalent for Transynd, all temps have decreased under like conditions. >>>Dan
 
Jeff,

I would get the fluid analyzed as I believe you got Exxon dextron 111 and not the synthetic equvalent to TranSynd.  Those temps are about what I had with dextron 111 before I changed to TranSynd.

Just my opinion,
 
It's late for me, so excuse the typos. --but I'm buying in Sault Ste. Marie a '94 Itaska Suncruiser with a 5.9L Cummins without an exhaust brake. I am adding one for the mountains of the west where I live. It has been difficult to find a Cummins dealer in the Springfield IL area to install as they don't have a way to read the codes on that older engine. Cummins Central Power in DesMoines can install the brake and may require new valve lifters. The Allison is the 6 speed MD3060? push button which I understand has to be reprogrammed after the brake is installed. ?How long and how big a job will that be?

This is my first diesel but I've many years in gas RVs --isn't that like staying in a Holiday In Express last night? 
 
The valve springs would need to be replaced if they are #30 springs.  You would need #60 springs to withstand the back pressure created by the exhaust brake. What kind of brake are you getting? Pac Brake and Jacobs are the two popular ones. I have installed two brakes on two different Dodge trucks with Cummins motors, but have not done a motor home. Kind of depends on how much work it is to get off the old exhaust pipe. On a 94' it could be pretty stuck......
 
Yes, I know the valve springs are part of the job. The choice will be made when they see the engine on the 18th.They are estimating between 30-45 man hrs for the job. Does that sound correct?
 
Bob,, I'm glad to see you are using a Cummins shop for the work, a 94 is not that old or obsolete that would be a problem for a reputable Cummins dealer/shop. I cannot understand why folks would consider taking this type work to an RV shop.>>>Dan
 
Bob,

The Allison reprogramming is a simple task for any Allison shop. They hook up their laptop and change a few settings.

Good chance you'll need the heavier springs, but 30-45 hours seems like a long time. I wish I still had the bill for when I had the Kenworth (they were Cummins certified, they were no Cummins Distributors in Vermont) dealer install the PacBrake on our 94 HR 8.3 engine. I just can't remember if we had the change the springs.

I think there are a few guys on the forum who had PacBrakes installed on 5.9 Cummins engines. Hopefully one of them will remember.

ken

 
We had our Extarder replaced in 2010 and the labor charge was $225 at Freightliner, about 2 hours.  We didn't have to change the valve springs but 30-45 hours for those sounds very high.
 
The "tell 'em the worse case scenario so we will look good when we finish sooner" principle  may be operating here They know I'm a Cummins old maid just gettin' hitched and know little about being married to one.
 
Hello Allisonman,  Will be brief. I have an Allison Md3000MH, Serial # 6510348767 in a Providence 38U Class A motorhome. Suddenly the downshift retarder stopped working as it should. Now when I switch on the retarder, the transmission shifts down to 2nd regardless of speed. I quickly switch the retarder off to keep the rpm's down. I do not have a fault code. There is a possibility that I may have had a code when this happened the first time, and I could have cleared it accidentally, as this is my first experience with an Allison transmission. Also the shifter is a single digit pushbutton WTEC III selector. Without the retarder switched on the transmission works flawlessly. I would like to say we as rver's appreciate you making your expertise available to us. Thanks, W61anderson

  from what your describing it sounds like the valve in your exhaust brake is either seized open or it is not getting air pressure to operate it.  the trans is doing what it is supposed to do, which is downshift as fast as it safely can to 2nd range when the exhaust brake is on.  I'd take a look at the air lines going to the exhaust brake first because I have seen a lot of them get holes burned through them from the heat.  you can usually hear the air hissing out when they get a hole in the line. 
 
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