Allison Transmission overheating

[barbican]

Hi

I got a problem with a transmission (Allison Transmission 9885) that overheats on neutral. The transmission is driven by an engine and connected to a pump (the whole thing is a stationary equipment). The transmission does not overheat while on gear and it shifts gears prefect, it only got this problem when in neutral. The cooling system is 100% good, all valves works good. what else is there to check ?

 

[btrueblood]

Have you consulted with Allison about using the transmission in stationary duty?

Fairly typical of automotive transmissions to not pump fluid (through the oil cooler) when shifted to park or neutral position; they are not intended to be operated for long duration in the neutral position, and the torque converter is still stirring the fluid and generating some heat. Idle, or better shut down the motor if in neutral for long periods, or install a secondary pump to keep the oil cooler working during those times.

 

[barbican]

btrueblood

The transmission is designed to be operated stationary (Allison 9600S). The transmission oil is cooled trough a heat exchanger that gets cooling water from the engine that drives the transmission (it uses the engine coolant pump). I didn't have any problems having it running for hours on neutral, now i got this problem, as soon as it gets to neutral the shaft stops and it heats up very fast. I would image that the transmission is on first gear on converter while it should be on neutral. Whats your thoughts ???

 

[tbuelna]

The transmission may not be shifting to a neutral condition. However, if the transmission was simply in 1st gear rather than neutral wouldn't the driven pump be turning? Sounds like there is something causing binding in the transmission when you shift it into neutral.

 

[barbican]

Tbuelna

The transmission output shaft does rotate when it is in neutral, It simply acts as it is in first gear while its set to neutral.


If you guys need more information (Diagrams,Specs,ect) just let me know.

Thanks..

 

[btrueblood]

Sounds like maybe one of the clutches, or valves driving the clutch, is stuck? Sorry, I'm no expert on Allison transmissions.

 

[boo1]

Check the filter, at low pressures it may not have enough flow.
Check fluid level

Check

http://www.allisontransmission.com/

 

[barbican]

Fluid level is ok and pressure is ok according to specs.


PS

is there any one you guys can recommend contacting that are good with these transmissions (9000 series).

 

[boo1]

Think of that changed.
Fluid change? Correct oil?
When was filter changed last?
Dip stick correctly installed?
Main transmitter connector tight, and installed correctly?
ECU connector tight?


try TransDiesel Service Departments 1-407-295-1221
or

http://www.allisontransmission.com/