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cbgenrich · 02-24-2009, 07:33 AM

It's not the cost ($300), but the constraint. The choices are these:

1) 3.15 Non-limited slip axle ratio
2) 3.55 Non-limited slip axle ratio
3) 3.55 Limited slip axle ratio
4) 3.73 Limited slip axle ratio

I know that higher ratios tow more weight, and lower ratios get better fuel economy and are somewhat quieter to drive in non-towing situations (lower RPMS).

Seems like 3.55 is the way to go, rated for 9700 lbs, in case I want to pull some bigger Airstream some day, without being overkill. It's also the most common and available.

Is there a down side to having limited slip?

If I buy a new truck with non-limited slip, will I regret it? Is limited slip a must have?

-CB-

ROBERT CROSS · 02-24-2009, 07:41 AM

2wd or 4wd

Limited slip highly recommended esp. for 2wd. Remember non-limited is really "one wheel" drive.

3:73 probably the best "all around" axle ratio.

Need more info for detailed opinions.

IMHO, I prefer having a TV with 4wd, it's been a fanny saver many times for us.

Gene · 02-24-2009, 07:51 AM

CB, living in Atlanta you may think you don't need 4WD, after all that's for people like Bob Cross who live in perpetual winter, but when you're trying to get up a muddy hill in a rainstorm in a campground, you'll be real glad to have 4WD. If you want to tow a large, heavy trailer during the life of the tow vehicle, best to go with 3.73 axle ratio. Some people go with lower numbers because the tow vehicle is a daily driver and they want better gas mileage, but when they are towing they may be testing the tow vehicle and wearing out very expensive components prematurely.

Gene

thecatsandi · 02-24-2009, 07:53 AM

Quote:

Originally Posted by cbgenrich

4) 3.73 Limited slip axle ratio

Seems like 3.55 is the way to go, rated for 9700 lbs, in case I want to pull some bigger Airstream some day, without being overkill. It's also the most common and available.

Is there a down side to having limited slip?

If I buy a new truck with non-limited slip, will I regret it? Is limited slip a must have?

-CB-

There is a downside. Right around 35,000 miles mine failed. I got stuck in the mud in two wheel drive with the trailer attached. I swritched to four and got out.
I had to have the entire clutch pack assembly replaced under warrenty. I am not wusr how it failed but they said the plates were burned up. The only way this can happen is if the pack was too tight when going around corners. THe replaced the pack and things are working better.
Get the limited slip but test it regularly for tightness or failure.
They did away with it on the Fords 08/09 and finally added 4 wheel traction control.

85MH325 · 02-24-2009, 08:09 AM

It depends on the truck. A limited slip is always a good idea. The new five and six speed trannys have all but eliminated the 4.xx series of rear ends. The lowest rear-end ratio available in a Titan now is a 3.35 in the "Big Tow" version and the tallest is a 2.94 or something close to that... and the Big Tow is rated at 9500 lbs. Now, that's just nuts... but for a 7500 lb trailer it'll do fine.

Toyota, OTOH still offers a 4.30 rear end in the Tundra... and they're rated at 10k lbs towing, a more reasonable approach IMHO.

I'd get a locker if it's available and you're buying new; if not at least the limited slip is valuable in either 2WD or 4WD. There have been a number of times when I've used 4WD just to get the rig moving on wet grass so I didn't tear tire marks into the campsite.

I haven't really kept up on the domestics.

Roger

Airslide · 02-24-2009, 08:15 AM

Great topic. This week I'm switching out my 4.10 rear axle to 3.55. It will be nice to keep up with traffic and bring the RPM down and if i hit a hill i can always pop it out of overdrive. Fuel mileage will come up too! No limited slip though.. just a set of duals on each side. Should be ok for what i need.

Vin

seeleylaker · 02-24-2009, 09:00 AM

Remember that the final drive ratio is what is important. A 4.30 differential with a 6 speed transmission should produce cruising rpms around 2000 or less in 6th gear-which usually produces fairly good fuel economy. The same setup will let you move almost anything in 1st gear. I prefer the limited slip and 4wd.

Gene · 02-24-2009, 10:30 AM

Michelle's post suggests something I hadn't thought about—doesn't traction control replace limited slip differentials? I think traction control (which is computer controlled) is far more sophisticated than limited slip.

Seeleylaker is correct about 4.30 axle ratio combined with 6th gear running around 2,000 or less rpm, but I'm not sure when towing if my Tundra ever goes to 6th unless I'm rolling downhill. The Tundra transmission has 5th and 6th as overdrives. I can't keep track of which gear it's in because I lose count when it's going through them—I can't make it through more than 4 gears. I have to watch the tach to know when it shifts because it shifts so smoothly I can't feel it. I have to look at the road sometimes.

Gene

cbgenrich · 02-24-2009, 11:05 AM

I'm not concerned about RPMs, fuel economy, or engine noise when towing. That is what it is. However, I hate to give up fuel economy or quiet all those non-towing miles, just so I can have a vehicle that *can* tow when needed. I'm looking for the right balance - not too little, not overkill. The comments here are helping me understand that.

-CB-

crispyboy · 02-24-2009, 11:18 AM

I wouldn't buy a truck without the limited slip. Just make sure when you have the differential oil changed that they put the additive in with the new oil. If they don't don't you will hear all kinds of chattering from the clutch plates when you go around a curve.
I would also skip the traction control. My brother has a Mercedes suv with "traction control". He was stuck in a turn lane on top of the packed snow. The thing wouldn't go anywhere until he figured out how to turn the darn traction control off. Just learn how to drive the vehicle and you won't have to have a computer compensate for your heavy foot.
I would opt for the 3.73 if you think your going with a bigger trailer. As others have stated this is a good all around gear ratio. Hopefully the transmission you select will have some good over drive gears for the highway.

3Ms75Argosy · 02-24-2009, 11:30 AM

Traction control is not the same... it will apply brake or reduce power to the slipping wheel.... if that one wheel does not have traction, you won't go anywhere... traction control or not.

I put a limited slip on my 1 ton 2wd van... it's made a world of difference... I can even notice it in the rain. In the snow, it adds stability to the van as well. With chains, I'm almost unstoppable.... just don't ask me to stop!

Marc

BillTex · 02-24-2009, 11:36 AM

I suspect you would be very disappointed if you don't get the 3:73 with this truck...

Bill

Silvertwinkie · 02-24-2009, 11:39 AM

I have had both limited slip and non-limited slip. I doubt I would ever buy another non-limited slip, particularly if it was 2wd. I have 4x4 now and also have limited slip. I would also get 3.73s if possible and is an option. Much easier on the tranny in all situations...of course now I have 4.10s.

cbgenrich · 02-24-2009, 12:19 PM

Regarding 4x4, I'm sure plenty has been said here and elsewhere about that matter. Still...

If you have it on your truck, that means you have the option to use it when you want to, even if you never exercise the option. If you don't, then you don't have that option. Always better to have options, but there's a price you pay for the option.

Reasons *not* to get 4x4 (I lean towards 4x2 but postings here have me thinking):

1) Degraded fuel economy (even if only because of the extra weight)
2) Initial cost higher
3) Tow & payload limits reduced (due to extra weight)
4) More maintenance issues
5) Vehicle higher off the ground

If not for these, everybody would always get 4x4? Did I miss any reasons why you wouldn't want 4x4?

-CB-

overlander64 · 02-24-2009, 12:37 PM

Greetings CB!

Quote:

Originally Posted by cbgenrich

Reasons *not* to get 4x4 (I lean towards 4x2 but postings here have me thinking):

1) Degraded fuel economy (even if only because of the extra weight)
2) Initial cost higher
3) Tow & payload limits reduced (due to extra weight)
4) More maintenance issues
5) Vehicle higher off the ground

If not for these, everybody would always get 4x4? Did I miss any reasons why you wouldn't want 4x4?

-CB-

I have had 4x4 tow vehicles since 1995, and have only used it on three ocassions, and on two of them, it would have been eintirely possible to handle the situation with a posi-track differential. Both my '95 Chevrolet K1500 Z71 pickup and my '99 Suburban have had different but expensive and continuing transfer case issues. My Suburban was purchased new and now has 200,000 miles and in that time, the $750.00 electronic transfer case control module has had to be replaced 11 times by two different GM dealerships. My '95 had the manual shift transfer case, but it was just as problematic as it always would stick in 4x4 and it would have to be take to a dealer to have the vehicle returend to 2-Hi (this vehicle was also purchased new by me). Today, I have adopted a policy of ignoring the 4x4 -- I won't chance shifing into 4x4 as I know if I do it will be sutck in 4x4 until I spring for another of the replacement modules -- at least as it is, when the current modules fails, the truck will be stuck in 2-Hi.

Good luck with your decision!

Kevin

hampstead38 · 02-24-2009, 12:55 PM

There are some good points here. Final drive ratio is more important the rear differential gearing. Modern five and six speed transmissions have influenced rear end designs. For the Titan, one of the best aftermarket additions is the TrueTrac.

Gene · 02-24-2009, 01:09 PM

CB, you've summed it up well the 5 issues regarding 4WD. However, it also depends on the vehicle. I have had 6 Toyotas and have never had any problems with the 4WD. All these vehicles have plowed through anything and there have been no serious skids or worse. Good M/S tires are also a big part of it and duals can't hurt as a substitute for 4WD. Incidentally, some SUV's and pickups do not come with M/S tires anymore. 4WD with an all season tire negates a lot of the reason for 4WD. A friend got the cheapest Toyota Tacoma with 4WD, but it has all season tires. He slid off my driveway and I had to drag him out with my M/S tires.

Thinking back to earlier vehicles with 4WD: 1978 Subaru, 2 Isuzu Troopers (on the 1986 one it didn't work, fixed under warranty; 1995 fine), 1990 Nissan pickup, 1972 Jeep (piece of junk in every way), mid '70's International pickup (another piece of junk, though 4WD worked fine), pretty much low maintenance, especially with newer ones. Maintenance is an issue with some, but not all manufacturers, and is much better than it once was.

Weight is a few hundred pounds and may or may not be important depending on how much payload you need; gas mileage difference depends on individual vehicles and on some, is minor. It does cost more, but resale is better unless you live in south Florida. The vehicle will be higher off the ground, though that difference is less than it used to be. It's easier to get underneath and fix things, but there may be some loss in safety because of higher center of gravity. But, different vehicles are more or less stable because of many factors that go into engineering stability so height alone is not the whole story.

Another question is where you use it and how much will you tow in what seasons? Will you go north in the Fall, Winter or Spring? Will it snow in Georgia? Will you want to visit places on dirt (possibly muddy) roads? Will you boondock in a wet grassy field? You may think you won't go there, but will you change your mind? You may not want to tow in snow, but you may have to? You may leave the trailer at a campground and have to get to town in mud or snow. But you may only go to Key West and will stay off the sand at Daytona.

Making these decision requires much research and analysis. You're going about it methodically and are honest with yourself, so you'll probably make the appropriate decision for you. I know Toyota dealers can find a specific vehicle from many miles away on their computers, so don't settle on what's close. I imagine any dealer that sells anything can do the same. Especially now they are very eager to sell you anything you want.

Kevin, sorry to hear about your horrible experience with your 4WD. I'd be screaming so loud they'd hear me in Detroit if I had the same problem, but they've been somewhat deaf in Detroit for quite a while.

Gene

hampstead38 · 02-24-2009, 01:20 PM

My family has been in the logging business for decades in Montana. It was the 1970s before the family business bought its first 4WD. During the 50s and 60s, standard equipment including a come-along, a high-boy jack and tire chains. When it comes to inclement weather, I'll go with V-Bar Tire Chains over 4WD. They aren't cheap, but they do have some giddyup.

I wager 99 percent of the folks who own 4WD vehicles don't really need them. And more than a few folks haven't figured out that 4WD doesn't make you stop any faster. I keep a set of chain under the rear seat of the Titan. I've used them once in the past five years. And having them let's me run nice, smooth AS radials year around rather than the mud/snow tractor tires.

Diesel1 · 02-24-2009, 02:31 PM

Get 3.73 and limited slip. Duals are horrible with a open diff, now you have two wheel drive except both drive wheels are on the same side. Traction control will help if you drive in a zombie like state, but mostly it will just burn up your rear brakes. 4x4 is nice but not very nessicary,unless, you live in mountain-snow country,then it is handy. Five & six speed trans are nice but no substitute for a lower final drive. For all around driving & towing 3.73 is a good choice. For straight towing you would be hard pressed to beat 4.10 gears. Adios, John

mikmilr · 02-24-2009, 04:07 PM

Don't forget to factor in the tire size for final drive ratio. A taller tire will lower the cruise rpm with a 3.73 where as a 3.55 may run nearly the same rpm with a shorter tire. My '86 suburban w/ 3.42 gear and 30 inch tires runs about the same rpm in high gear (not overdrive) as my old chevy truck w/ 4.10 gear and 35 inch tires. I also vote for limited slip with or without 4x4. Lockers work great in bad conditions but be careful on wet roads as you might find yourself sliding through a turn.

Mike