[doby48]

I had done an earlier post and didn't realize I ommited some of this information in this post.

I bought the truck used and the previous owner had changed out the gears, I don't know what they were changed to but was told the he changed them out for towing an RV. I got some tips from some guys as to how to figure out the gears based on turns of tire vs axle. The engine was installed about 20 months ago and is a 2004 5.7L Chevy Silverado Crate Engine with no additional mods.

Truck is a 1994 Chevy C1500 4x2 with POSI, Extended Cab, Long Bed. Current tires are P235/75R15. No topper on the truck but during hunting season there is a topper with no change in gas mileage or towing power. I have a 21ft Bass Boat that I need to tow and I am able to tow without issue when going down roadways, however, I have had difficulty pulling the boat out of boat landings, going up hills, etc (and have had to use a 1993 v6 Chevy Corsica to pull the boat out of the lake when the truck gets stuck). I have also had difficulty drivin down groomed dirt roads by getting stuck (and these are roads that compact front wheel drive vehicles don't have any issues driving down).

I would expect to be getting either decent power or decent mileage, but the place that I'm stumped is to why both my mileage is horrible and my towing power as well. If I failed to provide any needed information, let me know.

Thanks for any help anyone can provide.