blderman

Well I just got back from a 600 mile round trip towing a 25ft travel trailer with a loaded weight of about 7,200lbs. I noticed a few things of concern during the trip.

1. At an average speed of 60mph I only acheived a whopping 8.5 mpg....I guess I expected a lot better than that considering that when the truck is empty I get almost 22 mpg on the freeway.

2. When accelerating hard up a hill at about 60 mph I hear a loud whining sound that fades away at 64-65, the noise gets louder the longer and steeper the hill is when I stay at that speed.
I also notice a different pitched whining sound from 28-40 mph when there is no load. (I know it's not the turbo. This is a MUCH louder sound that resonates through the whole cab.)

3. I had to manuever the trailer though some rough/muddy spots so I put the truck in 4lo. While in that position everytime I went from drive to park the tranny would grind. Also while in drive if I hit the brakes too hard there would be a grinding sound.

4.Lastly, the Tow/Haul mode works great about 85% of the time. However when I got to winding hills where the speed and pitches vary alot the tranny felt like it was lost. It is way too happy to drop into overdrive and then when in downshifts into 3rd I don't feel like I am getting a solid connection between the engine and tranny like I should be.. I.E. the engine is reving hard and fast but there is little accleration. I really felt like the truck was going to fall flat on it's face at times...

Overall I love this truck but these few things have me a litte concerned about the longevity of it being used as a recreational tow vehicle. Any thoughts would be appreciated. Thanks.


P.S. I have 9,000 miles and no mods except for pyro, tranny and boost gauges.

J

Buzz

1. Can't help with that one.
2. That's probably the clutch fan locking up.
3. ?
4. The tranny was probably "hunting". Depending on the situation you probably needed to keep it out of overdrive so it wouldn't keep downshifting.

P.J

# 1) Is this IN overdrive, or Out? I would think you should see closer to 13MPG??
# 4) can be VERY harmful (at least to the 47RE),

Patrick Campbell

The 2005's will NOT let you lock out of OD. To me this is a problem.......

As for your mileage I would expect it to increase with further break in...what gears do you have?

quantrill88

as to the 4-lo grinding, Ive noticed that on both my 2000 and the new 04.5. Really seem to have to hold down on the brakes HARD to get it to shift smoothly.

blderman

3.73

Strick

A couple of weeks ago I did a maiden voyage with my 24' toy hauler. About 1000 mile round trip from Chicago area to Nashville and I averaged about 9.5 at about 65mph. I get anywhere from 14 to 17 empty.

And yeah I have noticed that grinding thing also.

huntram

No grinding here.

Empty 13 (in town, busy traffic, constant stops!) 19 Freeway 65 mph.

Towing 12-14 mpg pulling 10,000 TT with dirt bikes in bed of truck.

Brian

Ripper406

I think it may have something to do with mileage? First few trips non towing with our truck got us 13mpg, then slowly after the miles go packed on it went to 15.5mpg 68-75mph freeway cruising. But first time towin was maybe at 11000 miles 3000lbs tag along got about 9 first 20 miles. Then after that I started to get 13-14mpg. Fastforward a couple thousand miles and towing anywhere from 6500-9000lbs were now getting 13.2-15mpg towing. Running empty after a hard tow gets us near 17mpg now but it quickly falls back to 15's after 20-40miles. Weird

SBishop

Keeping in mind that I have a 47RE, I don't tow in OD unless I can keep about 1800RPM or better. If my rpm/speed gets below that, I slip it out of OD and drive in 3rd lockup. Pulling my 5vr, I can average about 11MPG. When pulling into some 35mph headswinds one trip, I drove in 3rd lockup at 2500rpm for a full day!! That run was considerably less than 11MPG!