Transmission Whine

[TomC]

This is also along the lines of GnarlyBus. The HT740 makes a whining sound in relation to engine speed. Could this also be the pickup tube sucking air because of a bad intake O ring? Good Luck, TomC

[HB of CJ]

Run the Bus Conversion until warm and take a tranny oil sample and send it off for analysis.  Might be abe normal wear inside the tranny.  Might also be air trapped inside the tranny oil.  Good luck.

[luvrbus]

Usually the whine is associated with the torque converter,sometimes if a shift kit was installed it will make a 740 whine

[Bill Gerrie]

I have had my V731 whine if it is even a little low on oil. Stops when heated up due to expansion of the oil. It is the converter that makes the noise.

[chessie4905]

I can't  think of anything in a converter that would cause a whine except a bad bearing or fins rubbing, but either one would not be temporary. Only the pump can whine from air in the fluid.jmo

[Bill Gerrie]

It is the air in the oil from being low or in some cases too high. The book states: a low fluid level will not completely envelope the internal filter. Therefore fluid and air are drawn into the system by the input pump and are directed to the control circuits and converter causing converter cavitational noises.
A high fluid level (too much fluid) will cause the clutches to be partially immersed in the sump fluid. Rotation of the clutches churn the fluid causing it to become aerated. The aerated fluid can also cause overheating
Make sure you are checking the oil level the proper way. Mine is 600 to 900 rpm in neutral, warm and on a level surface. A damaged or missing seal ring on the intake tube will also cause air to allowed into the system.       

[luvrbus]

TomC the lockup clutch is forward of the torque converter on a 740 sometimes on a fresh rebuild you will have a whine for a few thousand miles

[TomC]

I doubt I have even 1,000 miles on the transmission. I runs and shifts well-just has the whine. When the truck is at a more driveable state, I will take it back to the transmission shop. I'll have to pay for repair since it has been over 10 years. Thank you all for your responses. Good Luck, TomC