I currently drive a 2004 3500 Silverado 8.1 crew cab shining little over 500,000 and had it almost 4 years now. I love my truck it's great towing/pulling our horses and heavy equipment around but it over heats on the grape vine (I do live in California) if I keep rpm high and 2 times it reduced engine power so I was stuck in 90 to 100 degree weather. I'm planning to buy a Excursion 6.8 V10 or the F250/350 v10 heard those are pretty tough engines and better with a 5 star tune for pulling if I'm correct? I don't want to worry about it dying or over heating on me while towing heavy loads up the hill. (I am new to this forum)

 

How heavy will you plan to tow, how often climbing grades?

 

It sucks going up mountains with a decently heavy trailer. I just got back from a trip through Utah and Colorado pulling about 8k lbs and the V10 was struggling the whole time every time it hit a little hill. Some guys swear that changing axle gears makes it a much better pulling truck but I haven't done that yet since I've only had the truck for 2 months. Stock gears are 3.73 and everyone who tows agrees they are not right. The V10 does make better power at high RPMS and obviously gears will get it there. tow package had 4.30 gears but if you're on a little bigger tire, that's still not enough. Most say go 4.56 or 4.88. I'm leaning towards the 4.88s.

 

I tow about 11k little below sometimes 10. I hit the grades about 2 to 3 a weeks.

 

4:30's are reasonable.. 4:56 sounds about right to since I hitch up heavy 11k load. I hope the excursion power is good when we hit the grape vine a/c blowing etc.

 

If you stick with stock size tires the 4.56 would be good. How much elevation is the grapevine? I finally got to the top of the Loveland Pass Summit in Co. doing 22 mph in 1st gear foot to the floor. The elevation seemed to really kill power. I think that was about 11k or 12k feet.

 

Oh no leaving everything bone stock maybe a transmission cooler or so . Grape Vine is about 1,499.. I average 30 mph holding it in first on the shifter sometimes 2nd doing 40 but that's if I'm pushing it hard to floor.

 

 

Regearing is the answer. The better mechanical advantage from gears is apparent all over the rpm range, not just when revving the V10, which they like to do anyway. I recently drove a 4.30 equipped excursion on stock tires and it felt better than my 3.73 version all over. Gears are in my someday shopping liat