Transmission cooling

[ClintThrust]

The area I live in has a lot of hills and that doesn't seem to be sitting too well with my bus.

The fluid starts to go up to 350 pretty quick, even on pretty shallow hills.

Someone told me this particular Allison transmission isn't very good with hills so I thought maybe that's just how its gonna be, but one time I was driving along and it sounded like a second fan turned on, and the fluid went down to around 150. Then it turned off again forever.

Would it have a second fan for the transmission and where might it be?

And should I look for a way to fix the switch for this fan or just put in a manual one?

Fluid level looks OK to me.

[magnakansas]

That is too hot.... might also indicate transmission slipping. change the transmission fluid. add an air to oil transmission oil cooler, or if you bus has this already make it bigger. get under the bus... read the tag on the transmission.... betting you have 545 or one of the 540 series transmissions.

william

[Sehnsucht]

Allison as a brand isn't flawed but as William mentioned you want to confirm what model you have and the AT545 will be about the worst possible model for towing or hilly terrain because it lacks a lock-up torque converter so it generates excessive heat and reduces fuel economy - but it was cheap and many schools in the flatlands bought them long after better models were readily available.

It does sound like there's a transmission cooler and perhaps even a forced fan cooling solution but it doesn't sound like it's sufficient because of the temps you're seeing. More cooling would be better and promote longevity of the transmission

[cadillackid]

the "2nd fan" may have been your engine fan coming on Full speed which would help cool the transmission.. an external cooler with a fan should be easy to spot if you have one..