alright here are my trans mods, ATS triple disk converter, ATS pump kit, transgo shift kit, allison deep pan, alto clutchs, amsoil sythetic fluid.
last weekend i was pulling my toy hauler, about 9000lbs, i had made a stop and the truck was shut off, after i got back going again i forgot to put it in tow haul and wasnt paying attention to my gauges for awhile and after about 10 min of driving i realized it wasnt in tow haul and my trans temp reached 250* im guessing this is because i was cruising about 50 mph or so (shitty weather) so the convter obviously wasnt locked and it wasnt in over drive so this built up quite a bit of heat thru the converter. so i pulled over and let it cool down for quite a bit before pulling away again. obviosuly my fluid has a pretty bad burnt smell to it, should i flush it out and put new stuff, will it hurt driving around on this fluid? obviusly it i will heat up easier now that it is burnt but is it ok to drive on it for a little while? im going to change the spin on filter this weekend.
truck normally runs right around 200* or little less pulling trailer in t/h mode

I would not tow again until you flush her out and put new in...maybe new filters also. Around town driving is ok for awhile.

i cant say anything about the temps causing the smell, but i just switched over to Amsoil sythetic trans fluid and noticed it had a very bad burnt smell. Even just form the short drive home. But the guy at LubeX said all there sythetic fluid smells bad. I don't know if its just the Amsoil i used but the clean fluid smelt like Burnt Shit.

250 degrees is not all that hot. The fluid in my truck smells burn't also when new. Its as red as can be though. If the fluid is dark i would change it out. Dark fluid is a good sign that something is not happy in there.

250 is not that hot? I thought 200 was the max to stay at or below?

250 is not that hot and I seriously doubt you burned your fluid. Many fluids out there have a burnt smell right out of the container.

250 is not that hot and I seriously doubt you burned your fluid. Many fluids out there have a burnt smell right out of the container.


How hot is dangerous?

How hot is dangerous?

Depends on what fluid you are using. Using a 295 rated fluid, you are safe past 250F although I don't like that temp. Non synthetic fluids will not hold temps that high for very long.
When I started my cooler project a few years ago I talked to a lot of tow truck operators asking what temps they were seeing on an average using the same basic trans as we are and. They all reported 235 F+. They were all using TranSynd and most had over 200K mileage without any major problems except the usual C3/C2 clutches burning from time to time.

I agree with mike, smell isnt really a good way to judge the condition of modern ATF.

the allison is not prone to damage from overheating. You are not going to hurt it running it hot. The last allison I built for a customer was severely abused (big tune) and he lost a converter while he was far away from home with a trailer. IIRC he drove it a couple hours and a couple hundred miles at 270*+

when I tore it down the (stock) fluid was burnt but there was zero heat-related-damage otherwise to the trans. All the seals, bearings, pistons, etc were perfect.

I agree with mike, smell isnt really a good way to judge the condition of modern ATF.

the allison is not prone to damage from overheating. You are not going to hurt it running it hot. The last allison I built for a customer was severely abused (big tune) and he lost a converter while he was far away from home with a trailer. IIRC he drove it a couple hours and a couple hundred miles at 270*+

when I tore it down the (stock) fluid was burnt but there was zero heat-related-damage otherwise to the trans. All the seals, bearings, pistons, etc were perfect.
thats good info, ive run mine up to 235-240 pulling with no issues,fluid has never smelled burnt, although i did notice it runs hotter with the suncoast vs. stock(10-15 degrees) is that normal??