Allison Transmission Tech Advice

[rmcbrayer]

Hi Allison Man,
I have a 1999 Winnebago with a 5.9L 24V Cummins ISB, 275hp hooked to an Allison MT643 4 speed transmission. I have an opportunity to accquire a later model MD3060 out of a 40-foot bus with computer and shift pad at a good price. I'm interested in swapping it for my 4 speed. Aside from possibly having to modify the driveline, are there complications I should be aware of, and what would I need to do to properly interface this trans with the ISB? Thanks for the advice. RM

 

[allisonman]

Got the PM and have sent two back. You can pretty much ignore the first one, I've discovered a few things since I sent it.

Steep learning curve for me right now.

Thanks for your patience!

Dick

    no problem     

 

[allisonman]

Hi Allison Man,
I have a 1999 Winnebago with a 5.9L 24V Cummins ISB, 275hp hooked to an Allison MT643 4 speed transmission. I have an opportunity to accquire a later model MD3060 out of a 40-foot bus with computer and shift pad at a good price. I'm interested in swapping it for my 4 speed. Aside from possibly having to modify the driveline, are there complications I should be aware of, and what would I need to do to properly interface this trans with the ISB? Thanks for the advice. RM

this would be a pretty intensive swap to do.    first thing would be to buy an Allison trouble-shooting manual for the generation of Allison controls that you intend to put in.  this manual will have all of the wiring diagrams you need.  you will definitely need the computer that previously controlled the trans because it is programmed for that trans.    putting a computer with the wrong program installed in it on to a trans will result in disaster.  you may have to make a completely new wiring harness for the trans if the bus harness will not fit.  the manual will be essential for that.    then you will have to make a communication harness that will connect to the engine computer, the trans computer and the diagnostic plug.  the communication harness will supply the trans computer with a throttle position source.  without a throttle position signal the trans will shift terrible.  if the trans out of the bus has a retarder on it I wouldn't use it in a motor home as it would make the swap more difficult.

 

[Theberrys]

Aman

Today I replaced the output speed sensor. They had one locally for about $75.00. The cable and the connector both looked good so I just bit the bullet. The Allison distributor here needed the serial number from the transmission. Well as luck would have it National or Freightliner decided to put the muffler mount right in front of the Serial number plate of the transmission. In desperation I called Freightliner Customer Service and they gave me the Allison Serial number in about 30 sec. That sure beat removing the muffler to read a number. This is the second time Freightliner pulled my keister from the fire. They provided me a drawing of the tail pipe I needed to replace after the accident. I can't imagine how much data they have at there fingertips if they can come up with serial numbers on a 1998 Chassis.

Anyway when I pulled the output sensor, fluid did come out at a pretty good rate. Fortunately I had the new one in hand and stopped the flow after only a cup or so cleaned the  transmission and my hands of grease. You mentioned I should only get a few drops but I got a steady flow, so I'll check the level and see if perhaps it's overfilled.

I did notice the differences you mentioned in the old and new sensors. The metal spot sure enough was on the one I pulled out, and the rubber "O" ring looked to be a differant color.

I hope this is now behind me, and any Allison repair for $75.00 is a bargin.

Thanks for your help.

Dick

 

[rmcbrayer]

Thanks for the reply. This transmission is out of a 2006 40 foot Bluebird bus that has a wrecked front end, and it comes with the converter, computer and shift pad, but no harness. It was hooked to a CAT C7. Talking to the seller, I will need to provide a workable flex plate/starter gear (not sure if mine will work) and will definitely need the wiring harness. I could probably get a harness made up locally from a guy who does that, or might do it myself, and could get the driveline length changed if needed. I don't know whether it has a retarder, but I do have the S/N of the trans and can check with the local Allison shop to see if they can tell me. Can you tell me how to figure that out and what about the retarder would make it more difficult or not a good match to my motorhome? Also, can you expand on the intensivity of the installation? I understand the need to get the electrical wiring right. What about gear ratios, bell housing fitup, ie. will the 3060 converter fit in the 643 bell housing, etc. It looks to me like the bolt up would not be out of range from what I have done in other jobs.  Running the harness and mounting the computer and shift pad I can do. I could also get someone to help me program the trans to my engine. Is there anything that I am missing so far? Thanks very much for any further info/advice you can provide. RM

 

[rmcbrayer]

Hi Aman,

I found out that the trans does not have a retarder and I also found out what one is and how it works. I'm still interested in exploring the swap of the 3060 for my 643. Any further advice you can provide would be greatly appreciated. thx RM

 

[Renegade Driver]

I just bought a 99 Harney Renegade with an Allison MD3060 transmission. The total mileage is 57,000.  The transmission oil looks clean and was changed about 10k miles ago. How often would you recommend changing the fluid on an RV and whats the usual cost.  Should I use an RV dealer or go to a Catepillar or transmission shop.  The rig has a Pac Brake that works fine and also would appreciate some information on what the Mode button does to the shift pattern.

Any other tips would be appreciated


Thanks in advance

Pat Glazier
99 Harney Renegade

 

[Jim Godward]

First a question, what fluid was used in the transmission, synthetic - what brand, or dino, again what brand.  If dino, probably Detron 111, change is at yearly intervals and use a CAT, Cummins or truck maintenance shop.  Not sure of costs as the data is in the MH.  The last service I had for everything, engine, air, fuel and oil filters, fluids and other stuff was about $1400.  Pretty typical for an annual service with some long term stuff thrown in.

The transmission mode switch changes the transmission to an economy shift or the regular one

 

[Renegade Driver]

Thanks for the reply>>>The fluid is probably the Dextron fluid (red) and looks and smells brand new.  I believe that it has about 10,000 miles on it since being changed but don't know the time period.  I have a Cashman Caterpillar dealer near me so I will get it serviced with them.  Thanks for the mode switch question being answered.  The Tranny works fine and runs cool (less than 140 deg) and I would like to keep it that way !!

 

[allisonman]

Thanks for the reply. This transmission is out of a 2006 40 foot Bluebird bus that has a wrecked front end, and it comes with the converter, computer and shift pad, but no harness. It was hooked to a CAT C7. Talking to the seller, I will need to provide a workable flex plate/starter gear (not sure if mine will work) and will definitely need the wiring harness. I could probably get a harness made up locally from a guy who does that, or might do it myself, and could get the driveline length changed if needed. I don't know whether it has a retarder, but I do have the S/N of the trans and can check with the local Allison shop to see if they can tell me. Can you tell me how to figure that out and what about the retarder would make it more difficult or not a good match to my motorhome? Also, can you expand on the intensivity of the installation? I understand the need to get the electrical wiring right. What about gear ratios, bell housing fitup, ie. will the 3060 converter fit in the 643 bell housing, etc. It looks to me like the bolt up would not be out of range from what I have done in other jobs.  Running the harness and mounting the computer and shift pad I can do. I could also get someone to help me program the trans to my engine. Is there anything that I am missing so far? Thanks very much for any further info/advice you can provide. RM

Hi Aman,

I found out that the trans does not have a retarder and I also found out what one is and how it works. I'm still interested in exploring the swap of the 3060 for my 643. Any further advice you can provide would be greatly appreciated. thx RM

the flexplates on your engine will have to be changed, the pilot hub adapter will have to be changed.  you will have to get a starter ring gear for an ISB to bolt to your torque converter.  the 3060 bellhousing should bolt to your ISB.  you will have to give your Allison dealer your trans serial number so they can see if the stall ratio of the torque converter will be the same going from a C7 engine to an ISB cummins.  the dealer can provide you with all the part numbers of all the adaptation hardware to install it onto your ISB.  its good that the trans doesn't have a retarder because  the existing trans cooler in your coach won't be able to handle the extra heat generated when using the retarder.  the cooler line ports are also larger on a retarder model trans.  and your lines wouldn't work.     

 

[catblaster]

If no one minds I would like to make a humorous note....I firmly believe the Allisonman knows his "shifts". thank you!

 

[jbrown8988]

hello i sent you an email. I have a problem with my 03 chevy c4500. thank you for your time.

incase you didn't get it

I have a 03 c4500 8.1L and a couple weeks ago i was driving at highway speed and it dropped out of gear and stuck in 3rd. Stopped to get gas and started it back up and it was fine again. It was fine until 3 days ago... started doing it again and now its all the time. As soon as it shifts from 3rd to drive it will kick the trans light and go into limp mode. the drive indicator light flashes and if i dont shut the truck off and just put it in park then to drive i have no tranny...it won't move.

Thank you.

 

[allisonman]

hello i sent you an email. I have a problem with my 03 chevy c4500. thank you for your time.

incase you didn't get it

I have a 03 c4500 8.1L and a couple weeks ago i was driving at highway speed and it dropped out of gear and stuck in 3rd. Stopped to get gas and started it back up and it was fine again. It was fine until 3 days ago... started doing it again and now its all the time. As soon as it shifts from 3rd to drive it will kick the trans light and go into limp mode. the drive indicator light flashes and if i dont shut the truck off and just put it in park then to drive i have no tranny...it won't move.

Thank you.

    I read your e-mail letter after reading this post.  it is hard for me to pinpoint exactly what the problem is without a code to go off of.  just about any code will cause the 1000/2000 series to go into limp mode.  the best thing to do would be to have it scanned to see exactly what code or codes have set.  there are a few areas of the wiring harness you could check in the mean time that I commonly see rubbed through wires on these vehicles.  on the passenger side of the engine compartment pull the pins that hold the inner fender-well in place and remove the fender-well.  the Allison TCM is in an open metal box structure above the fender-well.  above the Allison TCM is the engine/chassis computer.  the Allison TCM has 2 connectors going into it that are red and grey.  trace the harness from the Allison TCM to where the inner fender-well was and inspect the harness. they rub through in that area often. you might have to pull the loom off the wires to inspect them.  the other wiring you may want to inspect is the internal trans harness.  on these years of trans the internal harness could rub on the trans case or pan and cause a short to ground.  the trans fluid has to be drained and the pan removed.  the pan gasket is reusable so after inspecting the harness you can just put it back in place and reinstall the pan.  other than that I'm just guessing as to what it could be without fault codes. 

 

[jbrown8988]

thank you. I was able to pull codes today. I dont remember the exact numbers but the first was... solenoid B stuck and the second code was...incorrect 4th gear ratio. We noticed to day that if you are easy on the throttle then it won't do it. but as soon as you hit the hills or get on the throttle it sends it into limp mode when shifting out of third.

 

[allisonman]

thank you. I was able to pull codes today. I dont remember the exact numbers but the first was... solenoid B stuck and the second code was...incorrect 4th gear ratio. We noticed to day that if you are easy on the throttle then it won't do it. but as soon as you hit the hills or get on the throttle it sends it into limp mode when shifting out of third.

        the C2 clutch is possibly slipping but these codes can also be set from erratic speed sensor readings.  sometimes poor speed sensor readings won't set a speed sensor code. what does the trans fluid look like, does it look burned?  if the fluid is not burned then you may want to check the yoke on the back of the trans.  see if you can push it up and down.  if it moves then the rear bearing race may have come apart and it will cause erratic output speed sensor readings and slipping codes.  if its tight then you could swap the input speed sensor with the output speed sensor and then drive the truck to see if there was any change.  rear bearing failure is caused from bad u-joints, driveshafts out of phase or, bad driveshaft angles. the other thing that can cause these codes is when engine power programmers are installed and the torque is increased beyond the transmissions torque limit.   

 

[SuperMike]

If no one minds I would like to make a humorous note....I firmly believe the Allisonman knows his "shifts". thank you!

I've always thought American jokes were bad, and this just confirms it.      :  ;D

 

[SargeW]

Hi Allisonman,

I have an 10' Winnebago Journey on a Freightliner XCS chassis.  It has the Allison 6 speed 2500 trans. It has about 12,000 miles on it now. I am still trying to get used to the shifts, or lack thereof of the new trans.  I had an 06' Itasca that was coupled with a Allison 3000 MH trans and LOVED it. The retarder, the shift points, the remote fluid checking, all were seamless. 

I have experienced that at times the 2500 does not want to upshift or downshift, even though the RPM's may be sky high.  Yesterday I was coming down a significant grade and had down shifted the trans to 3rd gear to keep the speed down. When the grade flattened off I punched the selector to put the trans back in 6th gear.  The trans hung in 3rd for quite a while, even though the RPM's approached 3000 RPM.  It finally up shifted.

It's not the first time the trans has hung either on an up shift or down shift.  Is this typical of this trans, or is there a problem with the software?  I use the mode button any time I am on the highway to get it to shift into 6th gear a little earlier.

I had the 5000 mile service done on the rig at Freightliner Gaffney and it got a clean bill of health.  Any thoughts?

Thanks, Sarge

 

[allisonman]

Hi Allisonman,

I have an 10' Winnebago Journey on a Freightliner XCS chassis.  It has the Allison 6 speed 2500 trans. It has about 12,000 miles on it now. I am still trying to get used to the shifts, or lack thereof of the new trans.  I had an 06' Itasca that was coupled with a Allison 3000 MH trans and LOVED it. The retarder, the shift points, the remote fluid checking, all were seamless.

I have experienced that at times the 2500 does not want to upshift or downshift, even though the RPM's may be sky high.  Yesterday I was coming down a significant grade and had down shifted the trans to 3rd gear to keep the speed down. When the grade flattened off I punched the selector to put the trans back in 6th gear.  The trans hung in 3rd for quite a while, even though the RPM's approached 3000 RPM.  It finally up shifted.

It's not the first time the trans has hung either on an up shift or down shift.  Is this typical of this trans, or is there a problem with the software?  I use the mode button any time I am on the highway to get it to shift into 6th gear a little earlier.

I had the 5000 mile service done on the rig at Freightliner Gaffney and it got a clean bill of health.  Any thoughts?

Thanks, Sarge

  in 2010 Allison introduced a lot of software changes in the programming.  in your case it may be the "tailored shift speeds" feature is not set right in your program.  Allison's SIL bulletin 27-WT-09 says that this feature allows a user (programmer) to modify the acceleration based pattern, kickdown and, hold override shift speeds (downshifting with the arrow buttons on shift selector).  this sounds like some of the symptoms your describing.  these newer Allison's should shift like a Cadillac, super smooth to where you can hardly notice shifts and shouldn't hang up like your describing.  I would take the coach into an Allison dealer and have them check the calibration with Allison D.O.C.    they can also give the Allison tech. assistance center a call to verify the calibration.

            when they did the service on your trans did they reset the filter life monitor?  if the prognostics feature is enabled then after fluid or filter changes the filter life and/or oil life need reset or a wrench icon will start coming on in the shifter display and sometimes the dash display center.     

 

[jbrown8988]

        the C2 clutch is possibly slipping but these codes can also be set from erratic speed sensor readings.  sometimes poor speed sensor readings won't set a speed sensor code. what does the trans fluid look like, does it look burned?  if the fluid is not burned then you may want to check the yoke on the back of the trans.  see if you can push it up and down.  if it moves then the rear bearing race may have come apart and it will cause erratic output speed sensor readings and slipping codes.  if its tight then you could swap the input speed sensor with the output speed sensor and then drive the truck to see if there was any change.  rear bearing failure is caused from bad u-joints, driveshafts out of phase or, bad driveshaft angles. the other thing that can cause these codes is when engine power programmers are installed and the torque is increased beyond the transmissions torque limit. 

Fluid is great! I did as you suggested and switched the speed sensors around. Didnt make any difference. I check all the U-joints, carrier bearing, & yoke no play at all.

This is so weird! we drove it this morning and as soon as it shifted to 4th gear it went into limp. shut it off and down the road we go, no problems. so i decided to go get a load of dirt and deliver it to a job and all the way there (15 miles) it was fine....as soon as i was loaded and took off...it went into limp mode when hitting 4th again. So then we get back home and it sat for about an hour...got in it to go down the street and as soon as i hit the gas pedal it went into neutral!!!!!!! Shut it off and was fine again. 

I am clueless...

 

[allisonman]

Fluid is great! I did as you suggested and switched the speed sensors around. Didnt make any difference. I check all the U-joints, carrier bearing, & yoke no play at all.

This is so weird! we drove it this morning and as soon as it shifted to 4th gear it went into limp. shut it off and down the road we go, no problems. so i decided to go get a load of dirt and deliver it to a job and all the way there (15 miles) it was fine....as soon as i was loaded and took off...it went into limp mode when hitting 4th again. So then we get back home and it sat for about an hour...got in it to go down the street and as soon as i hit the gas pedal it went into neutral!!!!!!! Shut it off and was fine again. 

I am clueless...

        from what your describing it sounds like the trans is slipping but to be sure your going to have to bite the bullet and take the truck in and have someone look at it.  the speed sensor readings are very critical to the trans computer and if the wires to the turbine and output speed sensors especially are rubbed through then it can throw these readings off and fool the trans computer into thinking that the clutches are slipping.  the computer then in turn puts the trans into limp mode when it sees that.  did you look at the wiring harness near the passenger side inner fender-well?  its a common problem area.    I wouldn't haul any more loads of dirt with the truck until this problem is solved in case there is clutches slipping.