differential wanted

THanks both for your input.

While I realise that Im putting excess stress on the componants I only use

4wd on pavment at higher speeds and disengages it below 30mph. (50Kms in my case) The handbook actually says that I SHOULD engage 4wd while on slippery or wet roads, strange eh.

Never mind, Ive learned somthig and thats pretty much why I use NGs.

If I learn one thing every day I will die a wise man. (I'll still be dead though)

Reply to
Scotty
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Idiots will be flamed. Asking relevent questions, as dumb as they seem, is not idiotic. Unless you ask the same question multiple times of course.

Feel free to ask anything relevent to the NG.

Scotty

Reply to
Scotty

Do this in the rain on lower speed (25-35 MPH) secondary roads. On wet roads, the system will be fine with lane changes and easy turns. You can also do this is in unpaved parking lots or on grass. There is no reason a part-time 4WD truck should ever be in 4WD at highway speeds. The same manual should have mentioned a top speed for 4WD. For many vehicles, 4WD top speed can be as low as 45 MPH.

You only need to activate the system for a few miles. All you're doing is moving the actuators and spinning the internals to spread lube.

Reply to
B A R R Y

'04 Tundras have manually locking hubs?

Reply to
B A R R Y

My logic, though, is that on this particular stretch of highway, the tires and system are only tracking straight...no stress to build up and release, unless there is another component of 4 WD I still don't understand !

The dogs are highly in favor of your suggestion !

Thanks for the input

Dean....

Reply to
D Larsen

Thanks, Bruce....as the other poster noted, the 04 Tundra does not have "locking hubs"....just a set of push buttons on the dash Any other suggestions for this case ?

Dean....

Reply to
D Larsen

Thanks, Barry....I don't recall seeing a number for top speed in 4WD. I'll dig out the manual again and see what it says.

Dean....

Reply to
D Larsen

Oh, one of those all-auto setups, never did like those - KISS principle, the less fancy stuff there is to break the better...

Go find a local dirt road and make a point of driving it once in a while, they're around. And as a bonus, they usually have lovely scenery.

For Los Angeles we've got a long stretch of Mulholland Highway that's still dirt - runs right along the spine on the mountains between Santa Monica and the San Fernando Valley, and they keep it well graded 25' wide for the fire trucks so you don't have to dodge very many potholes or big rocks. (But you still watch for them.)

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Reply to
Bruce L. Bergman

Your logic is flawed. The flaw arises out of the fact that the rear end is likely to be geared with 10 teeth on the pinion gear and 41 on the ring gear (4.10 : 1) and the front is likely to be geared with 9 and 37, respectively (giving you 4.11 : 1). So, your straight line travel can result in significant stress on the tcase.

Inflation of the tires can give a 0.01 difference in the front and rear tires.

Take the dog for a run ...

Good luck.

PS I'm not sure what the actual ratios are in your truck, but I just wanted to illustrate that the front and rear can easily be different by a couple of hundreths.

Reply to
Jeff Strickland

Jeff,

I will accept your assessment that my logic is flawed and find a nice dirt road to "lube" my transmission and run the dogs ! I'm a highway engineer, and I understand the differences in wheel tracking between front and rear wheels....we use "design vehicles" when designing highway curves, intersection radii, etc, and we use skid resistance values when analyzing crashs, skid marks, etc. When you get in to transmission gear ratios, though, you're going over my head

My inquiring mind wonders, then, why manufacturers design a vehicle with different gear ratios between the front and rear axles if this can be a potential source of problems ?

Just a rhetorical question....thanks again for your comments !

Dean....

Reply to
D Larsen

You're welcome.

Part of the reason is that the front and rear differentials (the source of the gear ratio calculations comes from the diffs, not the transmission, by the way) are physically different sizes, so they take a different diameter Ring Gear that mathematically works out to a different number of teeth. To calculate the ratio, one simply divides the tooth count of the ring gear by the tooth count of the pinion gear, the result is the differential ratio.

You are right, it would be ideal if the ratios front and rear were the same, and in an AWD (all wheel drive) system, they always will be because of the very issues you are talking about. Having said that, as soon as you put the vehicle into 4WD and attempt to negotiate a turn, the radius of the arc that the front and rear tires follow will cause the ratios to effectively become different, causing stress on the tcase if the vehicle is one with part time

4WD.

In a Part time system, they might not give you the same gear ratios front and rear, which is why part time systems are meant to only be operated in the dirt. The idea is that the tires need to slip against the ground to prevent the differences in the distance/speed/ratios from damaging the transfer case internals. If the transfer case is of the type that has a diffferential built in (this is typically accomplished with a viscous coupler), then the speed difference between the front and rear can be disipated without relying on the tires to slip on the ground.

Reply to
Jeff Strickland

Bruce,

Ya, it's a "lazy man's" 4 WD system....I don't even have to get my shoes dirty to switch in and out of 4 WD Hi or Lo !

The manual calls it an "A.D.D."...."Automatic Disconnecting Differential". My wife, a school teacher, says "ADD" is "Attention Deficit Disorder", which is probably the correct description for the type of 4 WD system I need

Ahhhh....Mulholland Highway.....many years ago I was stationed at Edwards AFB in the high desert....we used to haul our horses over the pass and down to Griffith Park (sp ?) with my old Ford F-100....lucky I never killed myself, the horses, or anyone else. Nowadays, I'll have to look around for a similar road here in Maryland !

Thanks again for your valuable input !

Dean....

Reply to
D Larsen

Jeff,

I recognized my ignorance on 4 WD systems....that's why I got hosed by the dealer and bought the extended warranty....figured if I screwed the

4 WD system up, at least I'd have some sort of protection !
Reply to
D Larsen

I think you bought the right truck and the right 4WD system, you just have to learn how and when you can use it without blowing it apart.

Reply to
Jeff Strickland

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