Hello John here, been lurking for sometime meaning to introduce myself but never getting around to it. For that I apologize because I have gained lots of great info here. I am on the road and needing some help with a problem I am having. I have a 1997 f250 crew cab 4x4 short box 7.3. Picked it up last November and this is the first time I have had it for a longer drive. Live in Colorado driving to KC Kansas was Hot! But problem started in Co. Original tranny replaced with a Jasper by original owner, who I bought truck from. I changed fluid installed a Mag-hytec oversized pan, installed a Auto-meter gauge. Driving temp will climb to 190-200, ever so slowly it creeps to 210 and then takes off to 230-240 and presumably higher in a very short time. Pull over put it in park temp starts to drop immediately, and settles in at 190-200. Can drive for at least 100-125 miles temp barely moves, then it creeps to 210 and off to the 230-240 range. Did this at least 6 times on way to KC.
Not towing, engine temp never moved from between the O and R on the dash Normal gauge. Same every time pull over idle temp drop drive for a 100 miles at least. Shifts normal purrs like a kitten. Any ideas? Did I say Kansas was Hot! 102
Temp. Thanks for any help and I will post pictures and introduced myself at a better time. John

 

John.goot to meet you.welcome.

Check the trans cooler situation.jasper likes to send their own very under size cooler with their trans .
If they eliminated the rad cooler and only use theirs then you have some serious work.take a look and get back.

 

Hi Fordman67 that's it! I can't believe they actually think that little thing is going to cool the transmission. Any sugesttions on fixing? Would an aftermarket one be do able?
Thanks again for the help

 

Well after further investigation I crawled under truck and checked it all out. The transmission lines run into the radiator up to a very small cooler of some sort, then back to transmission. I see whoever installed the jasper just cut the lines and have hose and clamped it back together. Going to go and clean everything at the car wash and see if that helps.

 

I would definitely install the biggest cooler you can find and get that small one outta there. I cannot believe someone cut those lines and used rubber ones!! I would be all over absolute PIZZED!! Also, I would not expect much out of that Jasper trans. they are not known to be strong units.