2018 3500 Aisin software update available?

[AH64ID]

My 18 Aisin never gets that hot either. It runs about 168 to 174. 174 is after backing my 13k 5th wheel into and up my driveway. I'm in Pennsylvania that's all hills and mountains.


Earl

Those are hills, not mountains. They can be STEEP but there isn’t any length or real elevation gain to them.

Generally the temps won’t get that hot above 20-25 mph since the torque converter is locked nearly all the time in TH. It’s the heavy, steep towing in 1st and 2nd with the TC unlocked below 20-25 that will generate heat. 8-10 mile grades at 15 mph has the time to generate some heat.

 

[EZeis]

Those are hills, not mountains. They can be STEEP but there isn’t any length or real elevation gain to them.

Generally the temps won’t get that hot above 20-25 mph since the torque converter is locked nearly all the time in TH. It’s the heavy, steep towing in 1st and 2nd with the TC unlocked below 20-25 that will generate heat. 8-10 mile grades at 15 mph has the time to generate some heat.

Definitely mountains. Not the Rockies but definitely mountains. Tuscarora mountain has me down in to 2nd and would be 1st if I would take the curves slower . Yes, it's called Tuscarora mountain, not Tuscarora hill. Has runaway truck ramp. Gear down stop. I think you may want to study up on the difference between hills and mountains. Hell, we have hills that are big as mountains with truck lanes and such. Either way I never see trans temps near 190F.


Earl

 

[AH64ID]

Definitely mountains. Not the Rockies but definitely mountains. Tuscarora mountain has me down in to 2nd and would be 1st if I would take the curves slower . Yes, it's called Tuscarora mountain, not Tuscarora hill. Has runaway truck ramp. Gear down stop. I think you may want to study up on the difference between hills and mountains. Hell, we have hills that are big as mountains with truck lanes and such. Either way I never see trans temps near 190F.


Earl

I've driven plenty of the PA roads with 8%+ grades and runaway truck ramps, mandatory truck pull outs, etc... they are still hills okay, baby mountains. It's more a joking reference to what are called mountains out east.. as we just call them hills out west.

2nd and 1st on curves isn't what will get trans temps up. Its a 8-10% grade for miles and miles at 15-20 mph with the TC unlocked the entire time, that gets the trans temps up.

Come out west and hit some of the remote roads with a decent trailer in tow and you'll see your trans temps above 174°.

Here is what I found on the stock file for a 2018. Aisin and 68RFE are the same.

Fan engages at at trans temp of 194°F.
Fan maxes at a trans temp of 234°F

Fan engages at a TQ Converter outlet temp of 237°F
Fan maxes at a TQ Converter oulet temp of 275°F

Bottom line... 190° is higher than most see, but it's nothing to be afraid of.

 

[DonFitzwater]

190 degrees for an Aisin is pretty darn hot, I've never seen mine get above 168. The fan would take some HP away but not enough to not let it maintain speed when in manual mode it keeps its speed. The fact it will do fine in manual mode and what I consider high transmission temps leads me to believe he has a transmission issue that could be as you stated, a software issue but may also be a mechanical issue with transmission. How many miles are on the truck?

Under 3000 miles

 

[EZeis]

I've driven plenty of the PA roads with 8%+ grades and runaway truck ramps, mandatory truck pull outs, etc... they are still hills okay, baby mountains. It's more a joking reference to what are called mountains out east.. as we just call them hills out west.

2nd and 1st on curves isn't what will get trans temps up. Its a 8-10% grade for miles and miles at 15-20 mph with the TC unlocked the entire time, that gets the trans temps up.

Come out west and hit some of the remote roads with a decent trailer in tow and you'll see your trans temps above 174°.

Here is what I found on the stock file for a 2018. Aisin and 68RFE are the same.

Fan engages at at trans temp of 194°F.
Fan maxes at a trans temp of 234°F

Fan engages at a TQ Converter outlet temp of 237°F
Fan maxes at a TQ Converter oulet temp of 275°F

Bottom line... 190° is higher than most see, but it's nothing to be afraid of.

Mind starting a GoFundMe campaign for me? So I can do some camping, I mean trans temp testing in the west?
I would assume the truck would notify you with a light and/or message on the dash if your trans got too hot. Maybe start derating the engine?


Earl

 

[AH64ID]

I would assume the truck would notify you with a light and/or message on the dash if your trans got too hot. Maybe start derating the engine?


Earl

Most likely, but referencing the above fan temps I am going to guess it would take quite a bit for a dash indication of too high of temps. Maybe someone with a FSM can look it up?

 

[CoastyAV8R]

The original post said he sees these temps when hes going down the highway at speed so the torque converter is locked up, so why the heat? Unless the transmission cooler is inop or thermostat isn't opening.

 

[EZeis]

The original post said he sees these temps when hes going down the highway at speed so the torque converter is locked up, so why the heat? Unless the transmission cooler is inop or thermostat isn't opening.

Trans cooler thermostat could be stuck??


Earl

 

[AH64ID]

Trans cooler thermostat could be stuck??


Earl

There is a thermostat in the output line. There are a couple of companies selling bypass kits, but not a lot of folks on here agree with deleting the thermostat.

It could be stuck, but it sure seems that it would get hotter than 190° without any cooling.

Maybe it’s not opening fully.

 

[Cummins12V98]

I would love to get mine to flow when I do a trans service. My 68RFE was a piece of cake to do a fluid exchange. Can't get any fluid to come out when popping the cooler line under the hood.

 

[EZeis]

There is a thermostat in the output line. There are a couple of companies selling bypass kits, but not a lot of folks on here agree with deleting the thermostat.

It could be stuck, but it sure seems that it would get hotter than 190° without any cooling.

Maybe it’s not opening fully.

Stuck would mean the same as not fully opening. As in stuck halfway or sticking from opening all the way. Faulty, bad, no good, broke, toast, defective, opening partly, debris in it, lost its calibration, etc. I really don't have a lot of time to type all the adjectives with the same meaning to cover my ass on what I post. Lol
Anywho, I've heard of those cooler thermostat units failing. How, why and such I don't know. Do they fail closed? Open? Midway? No idea. Would I bypass it, nope. Just offering an idea since his temp is 190F on the highway and not in 1st or 2nd pulling the Rockies for 6 hours straight with 60k trailer on.


Earl