Is my transmission toast?

[H3Jim]

1995 Prevost, B500 World transmission

When I push the R button, the left display changes to R, then the right one changes to R.  The engine will rev to redline with no connection to the rear wheels.

When I do the same with D, it does in fact move the bus forward.

I am hoping that there is some simple control, or wire that might be bad rather than a tranny rebuild.  I understand that a tranny rebuild might easily be in the neighborhood of $25k.  Just don't have that much right now.

Transmission fluid level is at the "full level when cold" and engine was on high idle for about 15 minutes.  Fluid does not smell bad, and looks clear on the dipstick.

Any ideas on things to check, or even better to get it to work again.  I may have to have it towed out of my driveway in order to drive it to the Prevost shop.  Certainly not usable like it is.

[Busted Knuckle]

Jim,
I certainly feel your pain as I had to replace one about this time last yr for different reasons though!

I wish I knew some answers for you but i don't.
I bet some of our more experienced guys here will have some ideas for you.
I wouldn't take it to the Prevost Shop though. I'd have it taken to the Allison Dealer. All Prevost will do is pull it out and take it to Allison for repair and put it back in or put in a rebuilt/remaned unit.
Might as well go straight to the source and cut out the middle man!
Good luck!
  BK 

[luvrbus]

Jim, how far are you from Cerritos that is the best Allison shop in Ca was S&J Chevorlet now Penske Chevorlet call and talk to Bob Ware he is retried now but is in the shop on some days sound to me like electrial problem if you can get access to a ProLink check the codes btw the last I heard it was around 10 grand for a rebuild at S&J for the B500    


good luck  

[stevet903]

Do you have any codes?  The procedure to get them is in the operators manual here:

http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=OM2157EN.pdf

It also says that it will inhibit shifting if the engine is above idle or high idle is on, which it doesn't sound is happening since you can shift into drive.

Steve

[Zeroclearance]

Jim have you replaced the two filters lately?   Are you running synthetic oil?

I'd pull the filters to see what you have in the pleats..  How many miles are on the tranny?

[niles500]

Unplug the ATEC from the power source for 10 minutes then reconnect and retry - HTH

[H3Jim]

Thx,

Almost all the miles on the bus are with synthetic oil in the tranny.  430,000 or so.  Filters changed two years ago.

[H3Jim]

about 2 1/2 hours from Cerritos, good to know about the Allison shop there.

I will check for codes tomorrow.

Removing power also sounds like a good idea.

The longer term history is when I came back from a trip, I got the bus stuck in my driveway - its a  new house and has not been paved.  there is a moderately steep hill, and the bus was stuck there for several weeks.  At first it was only because of the mud, but after the air leaked out, I could not release the parking brake, no air.  also the tag axle would not pump back up with air, and the kneeling system would not work.  having all the weight on the drives, with no tag support, lowered the back of the bus several inches, further putting it in the mud.  I was able to get it to go in reverse by putting it in drive first - even though the parking brake was on.  Still would not move an inch.  After I got the bus out and on level ground, the air system works fine now, but will not go into reverse.

Not sure if the air was a check valve, or even perhaps water in a tank that prevented air from flowing.  I discovered that if I let it completely air down over a week and a half, the first time it aired up, I had one shot to release the parking brake.  Then I took the fenders off and raised the suspension levers to lift the bus as high as the suspension would allow.  That was enough to get it moved.

So I think its likely that some tranny  logic was thwarted, and a reset might do it.

[stevet903]

Here's a better code reading procedure along with the table to decipher them. 

http://prevostparts.volvo.com/technicalpublications/pdf/pa1107-05.pdf

Do you get a check transmission light or a do not shift light?

Steve

[belfert]

In case you didn't know, Allison's suggested procedure to check the fluid level is run the vehicle until tranny is fully warmed up and then park on a flat surface and put the tranny in neutral.  Press the upshift and downshift buttons simultaneously.  The transmission shift pad will count down from 10 to 1 over several minutes.  At the end it will display OL and then Ok if the fluid level is good.

Unfortunately this doesn't help with why the B500 won't  go into reverse.

[luvrbus]

Jim if you got 430,000 miles from a B500 you did good most will last around 300,000 miles


good luck

[H3Jim]

There are no erro message such as Do Not Shift or Check Transmission.  It actually reads like its going into reverse.  They have one display that shows the gear selected, and the other shows which gear its in.  That display shows the R.

The rain is finally slowing a bit, I will get out there soon to do the hard reset on the brain.

[H3Jim]

Well rats, it pulled the plugs on the Allison ECU for 15 minutes and it still does not go into reverse.  Parking brake is acting up again too, won't release - although it does shift into 1st.

[niles500]

I don't have a world tranny and therfore no troubleshooting info - but I might suggest cycling starting it and attempting to shift (back and forth from N to D to R) a number of times - has worked in the past for me - also here's the reset procedure (I believe?) - HTH

Reset Procedures (Fault Mode)
Some of the more minor or temporary transmission faults
that would initiate a CHECK TRANS telltale light may be able
to be cleared. The following reset procedures may be
performed to clear a minor or temporary problem or fault.
Even the more serious faults in the higher gear ranges may
possibly clear for emergency continuation of travel
The most common reset procedure requires that the
coach be brought to a complete stop at a safe location, apply
parking brake, shift transmission to (N), shut off the engine
and wait about 10 seconds before restarting.
However, in a severe fault situation, the transmission
could possibly remain in the neutral position during an
attempted reset procedure. The transmission will remain in
neutral until the telltale is cleared or reset. If the problem
cleared, the telltale should light during its normal selfdiag
nostic check and then go out, and the transmission should
operate in a normal manner.
NOTE: Before turning off the ignition or shifting transmis
sion into (N), again note that the transmission may be
operated for a short period of time while in the fault mode.
If the fault is of a serious or damaging type, the
transmission will not allow shifting into or out of (N). If the
condition is minor or temporary, the telltale will not come
back on and the transmission should operate normally. If
the condition is more serious, the telltale will again light
and the transmission may remain inhibited or operate in a
normal Manner. The type of operation permitted by the
ECM will depend on the type of problem or fault existing.
Clearing WTEC Pushbutton
To attempt a reset and with the selector in (N), simulta
neously press the UP" and DOWN" (symboled) arrow
buttons twice. Press and hold the MODE" button until a
tone is heard. Next, release the button to return to normal
operation.
Clearing WTEC Shift Lever
To attempt a reset and with the selector in (N), push the
DISPLAY MODE" button one time. If equipped with oil level
sensor, push button twice. Press and hold the MODE"
button until a tone is heard. Next, release the button to return
to normal operation.

P.S. - sorry I meant WTEC on prior post

[niles500]

One more suggestion - before shifting or releasing the parking brake apply a hard service brake application and hold it while attempting to shift - HTH