HT740 slipping when about to shift?

[hogi6123]

When my HT740 is shifting into a higher gear, if I have the gas pedal less than about 1/2 way down it shifts like I would expect, pretty much immediately from one gear to the next.

When I have the gas pedal more than 1/2 way down, the engine RPMs go up when shifting, like the transmission is slipping or unlocked, for a few seconds before it shifts.  I think the more the gas pedal is down, the longer it does this between shifts.

This never happens while it's in gear.

There are no electronic controls for my engine or transmission.

Does anyone know what is causing this?

[Van]

I'm Guessing your modulator might be out of adjustment. do you have an air throttle? If not check the Modulator cable attachment point on your throttle linkage, might have come undone.

[hogi6123]

Thanks, No air throttle.  It looks like the modulator cable is attached but definitely could be out of adjustment.

[hogi6123]

Is the transmission supposed to downshift when I really stomp on the pedal while driving?

[Van]

That depends on speed, rpm's and gear selected.

Thanks, No air throttle.  It looks like the modulator cable is attached but definitely could be out of adjustment.

Good time to check your throttle cable adjustment.

[chessie4905]

"This never happens while it is in gear" Has to be in gear to move.

[buswarrior]

Where are you, and any former coach drivers nearby?

Find someone that has driven a few and have them take it for a drive.

Absolute waste of time and risk of making a problem, if there is none.

They are "automatic" in that they don't have a clutch, they are not very smart, and require driver involvement, for smooth and decisive operation.

The good coach drivers ran 2-3-4 themselves, with the shifter, not allowing the transmission to shift unless it was wanted.

happy coaching!
buswarrior

[hogi6123]

I know it's not acting normally.  I'm totally comfortable with checking the modulator cable movement and understanding how to adjust it.  I don't know how that could be a waste of time, I learn something else about my bus and maybe fix something.

[hogi6123]

"This never happens while it is in gear" Has to be in gear to move.

  But while the selector is "in gear" the transmission is not exactly "in gear" while it's shifting from one gear to the next.

[windtrader]

The experts weighing in. I only have some bits of common sense but if the transition really does take a few seconds to shift gears then something is out of adjustment. Mine has a couple slightly different oddities during some shifting scenarios but far more muted that I just ride off to aged equipment just acting its age.

[chessie4905]

Hopefully an adjustment will fix it but that slipping is wearing the fiber off the clutch plates.

[luvrbus]

Start by checking the shift cable adjustment make sure it's centered, check your pressures at the rear and torque converter could be weak clutches or it needs to be serviced does it happen in all gears