1975 flxible allison transmission problems, someone know trannys well?

[Busted Knuckle]

YOU CAN DO IT! BK  [/b]

[kbunnystarr]

  thanks BK!!!  yer just super!!!!!!!!!  I really appreciate you and all the guys on here!!!!!!!!!!!!   

BIG HUG!!!!  kbunnystarr/ Kristine

[Busted Knuckle]

Just doin' my part to help! It's great to see a young lady such as yerself interested in this hobby!
Just wish I was able to be of more help! But hey, you can do anything you set your mind too! BK 

[Hartley]

The Allison V-730 is a 3-speed Automatic Transmission, Hydraulically controlled. With a Lockup Torque Converter.
( Makes it seem like 4-speed ).

Education time:

Inside the transmission, The clutches for Second Gear and Reverse use the same gearset and clutch pack.

First Gear is wholly Hydraulic in operation.

If the Lockup is activated and not releasing the problem may be due to a faulty " Modulator " or "Modulator Assembly" which
if you have an air throttle uses a small air line to get throttle position air pressure to the side of the transmission. If you have a mechanical linkage throttle this could either be an air line or cable that runs from the governor housing on the engine down to the transmission.

If the "Modulator" is defective or the cable or the air line blocked , The transmission will not work properly, It may exhibit shifting problems like lockup problems or not unlocking or shifting down out of higher gears. It may also not want to shift up through the gears. It may also not let the transmission drop down out of lockup and back into First (Low) gear. This will BOG the engine down
and lead to a host of bad performance issues.

I doubt the Stone-Bennett shifter has anything to do with your problem. Most likely it all my just be in the modulator assembly, This is mounted on the side of the transmission and is field replaceable and serviceable.

I don't happen to have a picture of this handy right now but the modulator is an easy fix.

I hope that helps.

[gumpy]

Wow, this sounds very similar to what the previous owner is describing to her.

And the plot thickens!!! 

(Add suspenseful music here....)

The Allison V-730 is a 3-speed Automatic Transmission, Hydraulically controlled. With a Lockup Torque Converter.
( Makes it seem like 4-speed ).

Education time:

Inside the transmission, The clutches for Second Gear and Reverse use the same gearset and clutch pack.

First Gear is wholly Hydraulic in operation.

If the Lockup is activated and not releasing the problem may be due to a faulty " Modulator " or "Modulator Assembly" which
if you have an air throttle uses a small air line to get throttle position air pressure to the side of the transmission. If you have a mechanical linkage throttle this could either be an air line or cable that runs from the governor housing on the engine down to the transmission.

If the "Modulator" is defective or the cable or the air line blocked , The transmission will not work properly, It may exhibit shifting problems like lockup problems or not unlocking or shifting down out of higher gears. It may also not want to shift up through the gears. It may also not let the transmission drop down out of lockup and back into First (Low) gear. This will BOG the engine down
and lead to a host of bad performance issues.

I doubt the Stone-Bennett shifter has anything to do with your problem. Most likely it all my just be in the modulator assembly, This is mounted on the side of the transmission and is field replaceable and serviceable.

I don't happen to have a picture of this handy right now but the modulator is an easy fix.

I hope that helps.

[kbunnystarr]

  Thank you so much for taking the time to explain !!!!!!!!!!!!!  modulator assembly....ok, so if the fix isnt too hard and i can do it...what would you suggest i do first?  if you were advising me how to check what you are talking about.....cause im not sure where to start.........really!!! appreciate your input.

[Hartley]

Thank you so much for taking the time to explain !!!!!!!!!!!!!  modulator assembly....ok, so if the fix isnt too hard and i can do it...what would you suggest i do first?  if you were advising me how to check what you are talking about.....cause im not sure where to start.........really!!! appreciate your input.

The picture is of one of the cable operated modulators, I don't know which one you have but the air operated looks similar.
It may help you locate it on the side of the tranny next to the shifter mechanism....

[kbunnystarr]

i cant stress it enough how much i pperciate ALL replys, each and every person that took time and cared to respond!!!  thank you!!!  i leave on fri night to seattle, and will be driving my car from storage back to AZ< and i fell not near as desperate and stranded and sick to my stomach as i did when i left and its all thanx to the people that responded here!!!!!!!!!!!!!  i may not know the problem yet, but at least i have some thoughts and advice from guys that know way more than me in my arsenal instead of just being totally lost and bewildered!

i will let everyone know when im back to the bus and what i figure out and shat the issue is..........and im sure more questions from my end as well!  ) big hugs to everyone

[RJ]

Kbunny -

You might give Luke @ US Coach a call and describe your problem to him. 1-888-262-2434 M-F between 9-5 Eastern.  He's probably forgotten more about these powertrains than we'll ever know!  Great source of help, parts & service to the coach community, both commercial and us busnuts.  In Arcadia back in 2004, he mentioned a plastic gear on the V-730s that drives something that controls shifting, and it's common for them to strip.  $20 or less part.  Ask him about it.

The Stone Bennet shifter mechanism is on the curb side of the transmission, about the size of a soda can with a plunger on one end, pointing to the rear of the coach.  It's been awhile since I've played with one, but I think this is correct: 

With the engine off, push the plunger all the way in.  This is reverse.  One click out is neutral, two clicks is third (d), three clicks is 2nd, and all the way out is first gear.  Push/pull it in an out several times until you get the feel of it, then set it back to neutral.  (It might be the opposite of this - all the way out is reverse, all the way in is first - but I think it's the first description.)

Now get back in the coach and start it up, waiting for the air pressure to reach the governor cut-out (120 psi).  Keeping the parking brake set, use the toggle switch on the dash to shift into 1st.  Get out of the coach and go look at the Stone Bennet unit, and see if, in fact, it has actually shifted into 1st.  If it has, then try moving the bus.  If it hasn't, you need to figure out why (sometimes all that's needed is a little spray with a lubricant, like WD-40 or similar, on the plunger shaft).  You can also try manually moving the plunger to the 1st gear position, then seeing if the bus responds when you get back into the driver's seat.

Good Luck, and HTH. . .

 

[Busted Knuckle]

Russ excellent post with only one mistake! Besure to chock the wheels properly first! And it wouldn't hurt to have a helper hold the brake just to besure! We don't need that bus taking off and someone getting hurt!
Russ I know you already assumed this, but we gotta becarefull and make sure our "newer members of the busnut community" realize how important it is to always chock the wheels and make safety #1 ! BK 

[kbunnystarr]

  thanx guys, I leave tonight to seattle to get my car, will be back in touch around the 15th!   

[buswarrior]

Hey Russ.

I was thinking about that advice Luke gave about the nylon gear, but I couldn't remember if it included the V-730. I filed it in my head firmly that my HT740 had one, and that I need to do this bit of preventive maintenance on my own bus.

The description of Kbunny's trouble sounded like those symptoms that Luke shared.

As I recall, it was quite late at night too....!

happy coaching!
buswarrior