Rear end ratios 3.21 vs 3.92

I'm considering a new Dakota and was wondering whether to go with a 3.92 or the standard 3.21 rear end. Most of my driving is city and I occasionally pull around 5-6K pounds, but not frequently. Will the 3.92 have a gas mileage impact around town? I know it will on the highway but how bad will it be?

Reply to
Electrician
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I don't think you will find any Dakota that is rated to 6K with a

3.21:1 ratio, regardless of engine, transmission, or cab style for which you have not stated your intentions.

Frank

Reply to
Frank Boettcher

I wonder if that list is wrong. The user manual for my 2000 RAM 2500 CTD lists upper towing limits list about 15k for automatic and 19k for manual. This list shows the 2006 line for only about 13k for both.

If that is correct I think I will try to keep my 2000 truck lomg as possible.

GB

Reply to
GeekBoy

Yes and quite honestly, a Dakota will have a bit of a hard time with a

6k trailer and a 3.91 at times and be a lost cause with a 3.12. Take factory tow rating with a grain of salt here. Figure on about 60 to maybe 70% or the "rating" in the real world.

----------------- The SnoMan

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Reply to
SnoMan

Go with the 3.92. It will have almost no mileage impact around town. The transmission will upshift to the next to keep the rpm's in right range. You might notice some decrease on the highway, though. But it's not enough to matter a whole lot. You'll really need that 3.92 gear when you tow.

Reply to
.boB

If you want a point of reference you can go to the trailerlife.com home site and look up the 2000, see if it matches your user manual. Seems backwards though, most of the towing capacities derate the manual transmission.

You also should consider the Gross Combined Vehicle Weight rating, which is the weight of the vehicle, load and tow. Usually less than the tow ratings when you deduct the other stuff.

My Dakota is rated at 4800 for towing, but if I look at it from the GCVWR standpoint, drops to about 3900.

Frank

Reply to
Frank Boettcher

6k is a helluva load for a Dakota. If you really need that kind of towing capacity, I'd suggest you go to a full size Ram with the Hemi.
Reply to
Advocate

You don't say which engine, but I wouldn't recommend anything under

3.92 with any engine less than 5 litres, and I wouldn't recommend the 3.21 for towing even with the hemi.
Reply to
Ol' Duffer

In the case of the Dakota, I think that is because the largest engine is available only with automatic transmission. In most of the larger trucks, an NV4500 or Getrag manual is available that will take pretty much whatever you throw at it.

Reply to
Ol' Duffer

Thanks for the site reference. I'm planning on a quad-cab, V8 and 5 speed automatic so according to that I'd be limited to 5K with the 3.21 and could go up to 7K with the 3.92.

Reply to
Electrician

The Ram is too big to fit in my garage, I'd have just a couple of inches to spare. I have a 97 club cab Dakota that fits quite nicely so I'd like to stay with a Dakota. I've used my current Dakota to haul loads in the 5K range many times but never distances over 75 miles or so. It is a 5.2L, 5 speed automatic with the 3.21 rear and doesn't seem to have any great difficulty with 5K, other than getting about 10 miles to the gallon. So I'm thinking a new quad cab 4.7L Dakota will fit the bill quite nicely.

Reply to
Electrician

I guess I always thought the manufacturer rating would be quite a bit lower than what you could actually comfortably tow. But thanks for the advice.

Reply to
Electrician

I have both a Dakota and an f150. I also have a 6k travel trailer. I would not attempt to pull it with the dakota. as a matter of fact, I wanted to move my trailer about 20 yards to my front yard. My f150 was in the shop. I hooked up the TT to the dakota and I thought I broke the springs, it went so far down.

Good luck.

Reply to
Dave Lee

You have it backwards, it is a lot higher than you can comfortably tow with those vehicles. The only ones accurately rated and with some reserve are the diesels and Big Block powered P/U's (Like old Dodge V10's, old Ford 460's and GM 454's and 8.1's and Ford V10's somewhat too.

----------------- The SnoMan

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Reply to
SnoMan

If you had a 3.91 behind current truck you would have a different view and a Dakota QC with a 4.7 and a 3.21 with a 5 k trailer would be a slug and not make a good towing experiance and likely get even worse MPG that you get now. (deeper gears improve towing MPG)

----------------- The SnoMan

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Reply to
SnoMan

The list is right on.... you have a 3/4 ton RAM, dude... lol

My 01 Dakota with 4.7/auto/3:55 and 2wd is rated as max row 5100# Change to a 4:10 rear end and it's max goes up to 6,405# but that just means that it will get that much weight moving from a standstill..

It doesn't mean that it can STOP it or that the wheelbase is going to get longer or the suspension beefier to CONROL it.. YMWV Mac

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Reply to
mac davis

That's scarey... my 99 ram with 5.9 gas, auto and 3:55 gears is only rated at

7,200# We haul a 29' Travel Trailer that weighs a little over 6k loaded and there's no way I'd want to try that weight with a Dakota... talk about the tail wagging the dog... *g*

Mac

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Reply to
mac davis

Mac, do you use a weight distribution hitch? Sway bars? If so, your opinion on how much they actually help in controlling the load.

Frank

Reply to
Frank Boettcher

A sway bar works miracles. I know THAT from experience. A equalizer hitch also makes a HUGE difference, particularly on a heavy trailer and a light tow vehicle. When I towed the 17 foot Bonair with the Aerostar, if I had 150-200 lbs on the hitch it towned nicely - very little sway - particularly with TRAILER tires, rather than car tires. When I put a bike rack on the back, it was all over the road with 150 tongue weight - not much better at 200. The sway bar tamed it right down, even at 150 - and at

150 tye hitch hight was still very good - so I did not use a distribution hitch. The guy I bought it from used a distribution hitch on his AstroVan. He said without it, the lightweight trailer pushed the van around, or the bumper dragged. With the distribution hitch he could level it out, and have enough hitch weight to tame it down.
Reply to
clare at snyder.on.ca

My dealer complained the 3.21 9.25" config had considerably higher failure rates than the 3.55 or 3.92. They see a lot of 4.10 failures, but those are likely abuse-based errors from people buying too little truck...

I've got a 318 powered NV3500 (5 spd) 3.21:1 2WD 99 RAM 1500 club cab.

1st is too low of ratio for serious weight and towing - you'll have to play hot-clutch too get moving. I pulled my 92 Explorer XLT on a U-haul 'full' aluminum car trailer behind it, running in 3rd (3000ish RPM) and 4th maintaining 55-60 mph. Two weeks later the transmission failed. *shrug*

Personally I'd get 3.92 or 4.10 gears if I had to do it all over again... The fuel economy hit is small (and may actually be negative overall if you do a lot of city driving, or 45-55 mph back-roading) and the overall drivability of the truck improves so much, especially when towing or hauling.

JS

Reply to
JS

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