New truck or new gears?

[bobfowler]

I was kinda puzzled how a 3/4 ton van could have so much trouble on hils with a relatively small trailer such as our Base Camp or our 20" Argosy, until I discovered that my truck has 3.42 gears in the rear end. For the record, it's a 2000 GMC G2500 cargo with a 5.0 liter V8 and a 4 speed OD automatic, 115K miles on the clock.

I've been thinking about a new truck (don't we all), but since I discovered my gear ratio, I've been thinking about changing the rear to 4.10 gears. My on-line reasearch shows that I can expect about 17% more torque to the rear wheels with the 4.10. My question, will 17% make that much of a difference, or should I look for something with a bigger engine AND a beefier gear ratio? FWIW, my TV is my daily driver and I do 30-35 miles a day round trip to work.

[Gunnyusmc]

Putting lower gears in a vehicle with 115K is ?
I would trade up too a F-250 with 5.4 and 373 gears. I use this combo too pull my 25' 7000 lb Safari with no problems. I have 80,000 on this truck and put 225K on my 99 and 275K on my 94 without spending a dime on repairs.
If you intend too move up in size of Airstream, then look at diesel. I don't use them because I hate the maintance that goes with them.
I get 14MPG without and 10MPG with trailer.
You could go 410 gears but in will cut your without milage. My 99 had 410 and got 10 with or without.
The main reason for Ford is the Towcommand which is worth the price of the truck.
Just one openion.

Don

[jcanavera]

FYI, my 6 liter, 4.10 rear axle 2004 GMC 2500 van does between 10-13 mpg in city driving. Towing is close to the same range, dependent upon wind direction. Note this combo, according to the manual, allows towing in OD unless excessive hunting is occuring. I pretty much use the van for towing only or hauling when necessary. At this point it only has 20,000 miles so I expect it to be around for a long time. So for all intents it would be a thirsty vehicle for use on a daily basis.

Jack

[Beginner]

Bob
Do you tow the trailer in Overdrive (OD)?
I have a 91 Rally STX G3500 (12 Passenger dual air) with a 5.7 Liter (350) and according to my manafest in the glove box (G80, GU5) a 3.25 rear end ratio and positraction. I know its positraction for sure. My friend who owns a transmission repair shop (who is not at a loss for work) advises all his customers NOT to tow in OD, period. The OD unit cannot take the strain of the added load, it was not engineered to.
My gas milage at 63-65 is 12 MPG to 14 MPG in Drive (no OD) and I tolerate the hills ok. Of course I don't mind being in the right lane with the Semi's doing 30 to 40 mph up Afton Mountain but I get where I'm going. All things considered I'm happy. If I wanted to keep up with traffic going up the hills I'd have transplanted a 454 in it and put up with the 10 MPH overall. Just didn't want to loose the overall gas milage. I do have a large transmission cooler underneath with its own fan though.
Beginner

[bobfowler]

Originally Posted by Beginner

Bob
Do you tow the trailer in Overdrive (OD)?
I have a 91 Rally STX G3500 (12 Passenger dual air) with a 5.7 Liter (350). My friend who owns a transmission repair shop (who is not at a loss for work) advises all his customers NOT to tow in OD, period. The OD unit cannot take the strain of the added load, it was not engineered to.
My gas milage at 63-65 is 12 MPG to 14 MPG in Drive (no OD) and I tolerate the hills ok. Of course I don't mind being in the right lane with the Semi's doing 30 to 40 mph up Afton Mountain but I get where I'm going. All things considered I'm happy. If I wanted to keep up with traffic going up the hills I'd have transplanted a 454 in it and put up with the 10 MPH overall. Just didn't want to loose the overall gas milage. I do have a large transmission cooler underneath with its own fan though.
Beginner

The ONLY time I'm in overdrive is on flat terrain, and even then only if I think to engage it. I keep her in 3rd when anything is on the hitch. FWIW, I get about 10 MPG towing either the BC or Arg, 17 MPG without.

[Wayward]

Bob, 3.42 gears seem a bit steep for towing. How steep (and how low you should go) would depend on you tire diameter.

Can you post your tire diameter (or tire size)?

.............Scott

[BillTex]

Bob, as you are NOT 4wd, swapping final gears in the rear should be no big deal. We had two Suburbans; one with 3:73, the other with 4:10. Absolutely no measurable difference in mpg. Go for the 4:10, you should be all set. Neither of your campers is all that heavy. Save the new truck for when you have the spare change…

Bill

[Beginner]

Bob
Didn't mean to pluck a nerve. If I did I appologise.
I honestly thought my van had a 4.11 in it. After reading your post and answering same I checked the sticker in the glove box on the dog house. That explains the gas milage unloaded.
The only thing you have to decide upon is whether the added expense is worth the change over. Thats a personal thing. Just for a bench mark though, I rebuilt the rear end in a 82 Dodge van (all new bearings, seals and shim kits) and set it up my self and it still cost me over $500.00 (1988). Jet a good used one from a junk yard and drive it over the winter if you decide to change it out.
Beginner

[bobfowler]

Scott: my tire size is 225 75R 16 which works out to 29.3" in diameter.

Bill: I didn't think that there would be a big difference in MPG between 3.73 and 4.10, that's why I figured here was a case where a little more is better (15% more torque with the 3.73 vs 17% with 4.10).

Beginner: No problem, no nerves plucked! I had a quote for $600 for a re-gear from a local shop (gears included), or I could do it myself for about $250 ($125 for gears, another $125 for some special tools and the DVD). I'm inclinded to farm this out if I go this route though, if you've ever opened up a rear end and dealt with the mess and stink, you'll understand...

[jcanavera]

Just a quick word about towing in OD. There are vehicles that per manufacturers instructions can tow successfully and safely in OD. So remember there are a lot of folks out there who can offer advice on the subject but the only reliable information is what's in your TV owners manual. That will tell you if it's safe or not. Older tow vehicles, vehicles with smaller engines and lower axle ratios may not be matched with a HD transmission so 3rd gear is probably the only safe way.

In my particular case the transmission supplied with my 3/4 ton van is built to deal with the rigors of towing, although as I noted earlier you don't allow any transmission to excessively hunt as the resulting heat generated will destroy the lubricating properties of the transmission fluid.


Jack

[Wayward]

Originally Posted by bobfowler

my tire size is 225 75R 16 which works out to 29.3" in diameter.

Bob, with apx 30" tires, going up to 3.73 is not worth the cost of changing gears. I'd suggest at least 4.10 gears and you could go to 4.30 for some more pull without over-reving. Either one should make a big difference.

If you know what your, tire diameter, rear end ratio and your tranny's 3rd (or OD) gear ratio are, there are calculators that on the Web that will tell you your engine RPMs at a given speed.

......Scott

[3Ms75Argosy]

I say gears. That engine is pretty small to be hauling the van alone around. I switched out gears in an Astro and it made a pretty big difference. My 1 ton Dodge van (with a honking 5.9) has a 3.91 gears in it. It's geared ALMOST about perfect for me - in third, 75 is about the maximum I'd go without over-reving. It climbs hills at 50 in second at the max comfort revs. I do wish it had a shorter OD though - at times the engine speed sounds a bit strained on the highway. has a gear calcualator that will allow you to input your tire size, gear ratio, and figure out revs that you will be pullling at x mph.

I'd just put the info in and get an idea of where your highway revs will be at speed.

If your engine was any bigger, I'd suggest going the extra mile while you are in there to put a limited slip in. It's made a world of difference for me and my van in muddy or rainy conditions.

I say no, only because you may decide that you want more suds after all.

Some money ideas - put that 4.11 in.
See how it feels.
You may put a torquier cam in it, or maybe a cat back system for a few bucks.

Otherwise, used Chevy Expresses are on the cheaper side than trucks.
I hate gear fluid too.... stinks like, well, gear greese!
Marc