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Wayne, Journeyman
Category: Medium and Heavy Trucks
Satisfied Customers: 9818
Experience:  worked on, Gmc, Macks, Freight liner,Mercedes Benz,,Ford, sterling
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I have a 5.9 280 hp cummings with allison trans in my 1999

Customer Question

I have a 5.9 280 hp cummings with allison trans in my 1999 winibago 34 foot with a colorado toad and 60000 miles this week going to washington I had problem with overheating up hill rig left on cruise control.Temp gauge in hi normal but check engine light and transmission warning came on but did go out going downhill cooling off. Engine rps on level at 2500 and 70mph. On hill down to 2000 rpms 3rd gear at 45 mph. Out side temp aprox 95 t0 105. A lot of soot seemed be emitted according the look of my toad but I did not see unusual smoke. Is this normal or a possible thermostat problem?
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Wayne replied 1 year ago.

Hi I'm Wayne

I will help you with this

this normal, but not normal , I f this makes sense

the reason went to High temp,

is a dirty , clogged radiator, and trans cooler

I suggest to squirt it with dish soap, and was with hose

both sides and that will cure your issue

I hope this helped you

If this helped you

Please rate my answer 3 or more Stars

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Customer: replied 1 year ago.
I will try cleaning the radiator. it is a pusher rig and the trans oil cooler is a 2 foot long box on side of motor connected to engine water supply. It will take a while to get the rig, after washing radiator, onto the road to get a long hill on a hot day because it only heated up on the long climb.
Customer: replied 1 year ago.
The trans warning light also came on when hot but went out going down hills
Expert:  Wayne replied 1 year ago.


Yes let me know how it goes after wash