MCI-9 Transmission won't engage

[Kwajdiver]

Good Morning Guys,

I was all set to make a short run to the truck stop for fuel.  Press "D" and the tranny did not engage.  Tried to check the transmission fluid.  My dip stick looks shorter, than I remember.  I'm sure it's not going into the tranny.
Put about three quarts of fluid and still won't engage.

Do I need more fluid?  Didn't want to over fill it.


Bill
Still in Gulfport, Ms

[grantgoold]

Have you checked to make sure that a signal is getting to the transmission when you push D. It could be a simple as the button is bad and a no contact situation exsists. Can you hear the tranny trying to shift gears from neutral?

If it worked fine before, I would check the electric signal first and be careful not to overfill the tranny.

Grant

[Kwajdiver]

The tranny is not trying to shift.  Tried both "D" and "R".  Last time this happen, it was just low transmission oil level.  Of course then I remember having a longer dip stick.  Believe my dip stick has broke off.

Will check the switches.

Thanks, Bill

[grantgoold]

What's your plan retrieve the end of the stick? Drain, drop and search? Does you bus have a safety feature that will not allow shifting until the air is all the way to a safe zone. I cannot shift my bus until the air has exceeded 90 psi.

Keep us posted.

Grant

[Kwajdiver]

My dip stick is 23 inches long.  I need to someone to tell me if that is correct or not.  Seems like last time this happen, I added something like 5 quarts. 

My air is okay, I'm pumping up to 120psi.  Just added 2 more quarts, starting bus now,,, Will see.

Bill

[grantgoold]

That seems about right. I thought mine was a bit short as well. Can you tell if the end broke off. Are the gradations still on the stick (add, full...) Hope the fluid works. Are you leaking that much?

Good luck!

Grant

[Kwajdiver]

Added two more quarts.  Still not working, I'm now sure it's not a fluid level problem.  My dip stick looks broke on the end, does not have any writing on it.

Going to pull the switch panel and see what I have there.

Bill

[Kwajdiver]

The switch panel doesn't give up much information.  The buttons all work, but hard to tell about the electronics.

Any thoughts will help.....  I'm over my head,,, again   

Bill

[grantgoold]

Bill, can you determine where on the transmission the electronic signal goes to from the panel switch?  (Sorry, I have the traditional floor shifter)  If so, you can then have someone check to see if the signal is getting from the switch to the tranny. 

Does the panel switch have a fuse? You may want to check your repair manual and see if the unit has a fuse for the tranny.

Just some thoughts. Seems very odd that the tranny would just fail internally without some earlier indications.


Good luck!

Grant

[Kwajdiver]

Grant,

I don't find much in my manual on the tranny.  Shows how to change the filter, that's about it.  I was wondering about the a fuse.  Not a clue were one may be.

Bill

[makemineatwostroke]

Bill, what is the model of your transmission and maybe i can help

[Kwajdiver]

It's an Allison Automatic, four forward, believe that makes it an HT740.  A 1983 MCI-9.

Thanks for the help,

Bill

[makemineatwostroke]

Bill, on the drivers side on the transmission right above the pan it should have a tag with the model number.If your transmission is a HT 740 its probably a Stone Bennett shifter.let me know how deep your oil pan is and i will tell you how much of your dip stick should be down in the pan.But we need the model of the transmission to help.there should be a plug on the pan where you can check the safe level for the oil above where the dip stick tube is mounted to the pan.

Bill this sounds like a oring on the pickup tube being you had to put more oil the last time when it happen,its a 1.00 oring but cost 80.00 for the oil and a new gasket

[NJT5047]

What about setting the brakes and before the engine and trans get too hot  to dink with,  crawl into the RH engine service door and manually shift the trans into drive or reverse?  Have someone hold the service brakes maybe.  Even with an SB shifter, there's a linkage that can be moved.
Get the high idle off, and don't manually shift the transmission before the low air buzzer goes off.   You may not have enough brakes to hold the coach. 
If it goes into gear, the trans is OK and the Stone Bennett has issues.
Obviously, make sure that the bus cannot move when doing this sort of thing. 
I'd expect it'll shift.  If it was working when you shut it down, it'll very likely work now.
IMHO, the broken dipstick isn't worth going after until you're ready to service the transmission filter and change the oil.   The broken tip should lay on the bottom of the pan. 
It will not pass thru the pan filter. 
If manually shifting doesn't make the trans go into gear...bummer.  Major bummer!~
You don't have an ATEC (HT748) trans?  Could have been retrofitted?   Not likely, but possible.   Does your transmission push button control have round buttons or is it a square buttom touch pad with an Allison logo cast into the upper surface? 
Another way to ID the units is if you have a big bundle of wires going into the PAX side of the trans, it's an electronic unit, if you have a cylinder and shift linkage on the side of the trans, it's an HT740. 
Good luck, JR

[makemineatwostroke]

Bill,there was another manufacture of a shifter also but i can not remember the name right now but it will come to me. If you do have a Stone Bennett air shifter that is not working 95% of the time the problem is caused by dirty air and can be a simple repair. look on the passenger side if you have a box 2in thick 4in wide and about 6in long with a rod in the center with wiring and 1 air line that will be a Stone Bennett shifter.Check it like JR said and if the shifter is not the problem i will tell you how to check the pressure and we will go from there