I have a 1999 powerstroke w/automatic tranny, My transmission temp reached 248 for a short period while pulling a trailer up a steep incline(alarm started flashing on Edge display). Once I leveled out the temp dropped back and alarm cleared. What is maximum temp and how long can a person run in alarm before damage occurs ? I have 70k miles on odometer. Is this transmission equipped with a fluid cooler ?

 

250°F is Ford's limit for that transmission. If you reach that limit you should find a safe place to stop and fast idle in park or neutral. DO NOT SHUT THE ENGINE OFF WITH THE TRANS THAT HOT!

1999 trucks left the factory with one air to oil cooler for the transmission. That was soon proven to be inadequate. Mid year 2000 Ford added a second cooler inside the engine radiator. Many 1999 trucks were retrofitted with a new radiator with a cooler.

If your truck doesn't have a radiator cooler I recommend changing the radiator for one that does. Another good modification is to replace the current air to oil cooler with one from a 6.0L truck.

 

Thanks Mark, kinda figured there was an upgrade of some kind. Looks like the change to the 6.0 air to oil cooler is the cheapest option for sure. Will this do enough cooling to keep me out of alarm or should a person just spend the cash and have a new radiator installed ? Is Ford the only place to get these upgrades or is there an after market supplier of parts(will install myself), thanks again...Ron

 

Radiators are available anywhere that sells auto parts. Is the 6.0L cooler enough by itself? Maybe, maybe not. Did you look to see if your radiator has a cooler?

 

Thanks again Mark, my particular truck has the air/oil cooler. Ive checked with a local diesal truck performance shop and the hot hookup is the 6.0 cooler to replace my stock one. It fits where the old one sets and doubles the cooling capacity, they also mentioned a kit that changes the cooler bypass where oil doesnt bypass anymore, thus allowing more oil flow thru the cooler. Its kinda pricey but well worth it I think, thanks again !

 

A 6.0 trans cooler is very cheap compared too a 2,500.00 re-build! Its cheap insurance!

 

Before installing a kit to replace the bypass make sure you have enough money to replace the transmission. Eliminating the bypass can destroy your transmission.

The bypass is there in case the cooler circuit gets restricted. After the ATF leaves the coolers it is returned to the rear of the transmission and used for lubrication of the rear half of the transmission. If the cooler is plugged the bypass opens and supplies the rear half with lube. If the bypass is eliminated and the cooler is restricted the first you will know about this is when the transmission self destructs.

If the cooler circuit is flowing normally 0% of the flow goes through the bypass and 100% goes through the cooler. How can you improve on that?