Hi I have a 1969 PD 4107 8v 71 Allison 3 speed toggle switch shift.
I was coming out of Kingman to Havasu. on the way down the hill after the crest, the the bus would not shift out of first. I pulled over, and pulled the governor out, it seemed to operate . I cleaned it and I got it to shift to drive on the frontage road but once it down shifted and I got back on the highway it never shifted out of first gear again. any ideas? Thank you, Mike Sarah and Alex
Confirm that the electric shift mechanism isn't throwing all the way to 1st and holding it there?
Might be doing exactly what it is being told to do?
Happy coaching!
Buswarrior
Thank you. I did check while my wife shifted. It is cycling through the gears.
If the fluid is low on the v730 it will not shift out of 1 gear check the fluid first
Hi, thank you. I did check the fluid level. It reads right around the correct level when checked cold. And before start it is up in the fill tube some.
I have ordered a new internal filter plus an external spin on filter. I read somewhere that plugged fuel filters could also be a culprit. although I can start it anytime to go empty the waste and fill the propane. It just stays in first.
The proper way to check a V730 is oil warm and idle at 600 to 900 rpm. The cold check is just to make sure the level is safe to start it up.
I checked it running and warmed up. It shows correct level of fluid.
Dipsticks can be wrong. The bus must be level, or it could be the wrong one. I would add one gallon of tranny fluid and see if it shifts. And I don't think your problem is first to second, but second to third.
There is a second to third shift inhibitor which comes on if you are one gallon low, maybe it is bad.
Thank you, I will do it.
I kept the RPMs around 1800 and did an average of 25 miles an hour from Kingman to Havasu.
Close to the drive shaft flange there is a plate with 4 bolts inside the cover is the governor if the plastic gears have broken it is not going to shift to 3rd gear
I did remove the governor. It looks great, I cleaned it and the bus did shift through all gears until the first time I had to stop. It then went back to not shifting. I even pulled off of the next exit and pulled it out again. I had no results that time.
You didn't pull the modulator out and loose the pin ?
Well I do not think so. It came out pretty straight forward. I can not remember seeing anything like pin.
Quote from: Winging it on January 08, 2020, 12:53:12 PM
Well I do not think so. It came out pretty straight forward. I can not remember seeing anything like pin.
You need to pull it and check for the pin they fall into the pan,lol every old Allison always have a few extra pins in the pan BTDT
All right, I have been looking for videos of where the modulator is. can you tell me where it's located? I will do it right away.
1st do you have a air throttle ?
I do not have air throttle.
The modulator is at the rear of the transmission on the curb side with a cable that goes up to the throttle
All right I will check it and get back to you
Get your book out and look for the governor screen. Its inside a port with a plug just above the oil pan at the driveshaft end of the trans. It is a small cone shaped screen. olebusman btdt
I think this is the modulator it does have a cable going up to the throttle linkage. What can I expect even I remove it and what should I look for. There are no air leak to the transmission.