Allison 5sp: Running Hot

[RvrRnr1000]

All,
I put some 40's (20in Rim) on my truck and it looks better than it ever did but my engine temps and tranny temps went thru the roof especially when I travel the 40 out to the river.....
I am kind of tired panicking about the temps but my thick scull wont let me go back to 37's or 38's so any suggestions.....electric fans.....re-gearing the rear-end......What will be the best bang for my $$$$
RvrRnr10000

 

[Robby05]

What's the temps?

 

[dirty_max]

wait... you are running 40" tires on stock gears?

 

[RvrRnr1000]

Yeah, unfortunately stock gears......if I remember correctly they are 3.73's.....what should I go down to and how much are a set of gears?????

Temps are running at 240º to 260º going up the grade and the trans temp was also at 260º..... most of my driving is around town but I think that I need to get something planned out....don't want to burn up my trans.....or motor....

 

[brokesmoke]

Ouch.... Poor Trans..

Gear that thing!

 

[RvrRnr1000]

??What sizes are there....4:10's???? What would that cost?????

 

[NinjaMax]

Man with 40's I'd go 4:56

 

[THEFERMANATOR]

??What sizes are there....4:10's???? What would that cost?????

HOLY CRAP! I hope you at least run tow/haul mode to try and keep the converter locked in better. With 3.73's and 40 inch tall tires, your not getting lockup in 5th regular mode until about 65. I would also say you better start saving for a trans as I bet with those temps your converter isn't very happy anymore. You also better get your fluid changed because regular DEX/MERC fluids won't last very long once temps surpas 225 or so for any length of time. For that big of a tire, you better think about a set of 5.13 gears. They are available aftermarket(don't think AAM makes a set that low), and to do both axles you are going to be in it for around $1200 in parts(provided you still have the 9.25" front axle, but at that height you've probably gone with a SFA conversion already). To have gone that tall, you should have regeared BEFORE going to that size of a tire.

 

[Chevy1925]

40" tires wont cause a truck to overheat by its self up a grade.

are you pulling a trailer when this happens?? there is not one person i know that runs that size tire and has overheating issues with the truck empty even in the middle of summer here in az.

 

[dirty_max]

40" tires wont cause a truck to overheat by its self up a grade.

are you pulling a trailer when this happens?? there is not one person i know that runs that size tire and has overheating issues with the truck empty even in the middle of summer here in az.

huh? keep in mind the ambient air temp this time of year.

 

[fast03]

you should be running 4.56 for sure. Change trans filter lately? Towing?

 

[Chevy1925]

huh? keep in mind the ambient air temp this time of year.

my truck has had 37s for over 8 years. 7.5 of those years was with stock gears and ive pulled 12+k with my truck weighing in at 7800lbs. at no point has it ever gotten close to being hot unloaded. it also would pull any hill i wanted at 50mph when it would start to finally get hot and id slow down, this again only in the middle of summer with 110* ambient temps, no oil cooler, no twins. i have two other friends who had 40" tires on their trucks. one of which pulled 6-7k at a time to desert races, the other drove around daily and towed the same with out issue.

its not a tire issue to cause a truck, unloaded, to overheat. there is other underlying causes

 

[DIESELMAFIAPER.LB7]

I agree with James I'd be looking into some new thermostats and cleaning the cooling stack out and a good trans flush

 

[THEFERMANATOR]

you should be running 4.56 for sure. Change trans filter lately? Towing?

If you do the math the equivalant ratio would be roughly 4.88, but add in the extra mass and 5.13's is a MUCh better choice. And runnign around with the converter unlocked all the time at highway speeds with one heck of a load would sure cause for some high temps, espescially up a grade. Not saying there isn't other issues, but he needs to fix the obvious one first.

 

[Chevy1925]

smh... spending his money for him without even giving recommendations on what to check BEFORE throwing away money.

 

[dirty_max]

simple solution, put stock size tires back on and see if it still overheats.

 

[RvrRnr1000]

Thanks Guys for the plethora of information.....Ya as it stands the truck is pretty much empty 95% of the time and from what I just looked at about 1 hour ago is that when they did the Body Lift they must have thrown away my radiator shroud from the bottom part of the truck.....I think that it might not be pulling all of the air thru the radiator that it could be if it still had a shroud!

Maybe I cant run a lower shroud because of the body Lift......?

Also to answer another question the truck is a 2 wheel drive.....Not 4 wheel drive.....Sorry.....so who do I call here in California for some 4:56 gears.....How much for one set?

 

[Chevy1925]

Fix the fan shroud, can you hear the fan come on when the coolant is that hot? Also, of the truck is an 03-04, are sure the gauges aren't bad? A scan tool that can read coolant and trans temp while driving would eliminate that issue

 

[hondarider552]

Body lift to clear 40's?


Why?

 

[RvrRnr1000]

Does anyone know of a place that will make a custom radiator shroud for my truck????

The body lift was needed to keep the tires from rubbing....