2nd Gen Non-Engine/Transmission T-Case +Speed = Bad?!?

[biggy238]

I've never used my T-case over 25mph until last night. . I was in a strip mine and hit it hard to see how it would launch. . It did good.



I pulled out onto the highway... I was under the impression that people used 4wd to launch at the drag strip to aid in traction???



This truck Howls like something is getting ready to blow up between 35-55. . and then quitens down again above 55 (took it to 60) in 4wd high.



What i'm really curious about is should I worry about the T-Case or is it the difference in the thickness of the ring gears that i'm hearing. . I mean, the rear pinion and ring set have almost 200K of wear on them and I doubt the front pinion and ring have ever been loaded for more than 200 miles in it's entire existance.



I was just wondering what everyone else' experience was on this.



I don't have a problem at all not running 4wd fast, I just thought people were running them successfully at higher speeds.

 

[nutter3]

You're right, people do run them at higher speeds. I drive on the highways all the time in 4Hi. Drag racers race in 4hi. You must have something wrong in your tcase if it's making bad noises.

 

[astevenson]

You should make shure all 4 of your tires are worn the same. If your front tires are at half tread and your rears are at 3/4 to full tread that could make a difference on solid ground. And also have you checked your tire pressures. Make shure all tires are aired the same. Also I beleive most people a launching in 4 wheel and kicking it back to 2 wheel shortly after launch.

 

[todt061458]

Another question you must ask yourself when was the last time I checked/changed my T-Case fluid? or adjusted the T-Case. do you have water in your T-Case fluid?

 

[biggy238]

Checked the fluid level 20k miles ago. . I was planning to change it this weekend as I didn't change it before.



I, Too, thought that the 4wd was kicked out shortly after a launch, but with the noise at such a low speed I thought I would run it up higher.



Give me more details on the T-Case adjustment please. . I've never serviced a Tcase before so it is new territory.



The tires are all worn the same and within 3psi of eachother.



I've thought about it more since posting and it seems like it was groaning last winter too... I'll investigate this weekend.



Do they take the same fluid as the transmission? +3 or +4??



Thanks for the help guys.

 

[BigEasy]

In 4H I have used mine in wet and snow weather with no problem running 80 mph and I have done this since I bought the truck.

I'm not trying to be a jackass, but why are you running 80 mph if you feel the need to be in 4WD?!?!?!

 

[JR2]

I have done many launches on the drag strip in 4 hi. I have tired shifting out of 4x4 during the run, but the CAD does not release untill you let off the go peddle so I just leave it engaged. Been in 4x4 up to 98 mph, but only for 13 seconds.



4x4 at 80 mph on the highway is a waste, why in the world would it be necessary to be in 4x4 if its safe to drive at 80??

 

[JFaughn]

I'll be looking for that adjustment info also.

 

[Tinman]

On the few occasions there is snow or ice on the road, I run 4HI all the time. I don't want to realize I should have been in 4 HI when I'm headed for a ditch and can't steer. Last year, my wife and I got caught in that big snow storm in the Ohio valley on the way to Nebraska for Christmas. I was in 4HI most of the day at low highway speed, no problems.

 

[JasonCzerak]

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Also I beleive most people a launching in 4 wheel and kicking it back to 2 wheel shortly after launch.

50% true on the drag race for a stock T-case.



If they are running auto. the T-case can't not disenguage under a load. If it's a manual trans, once you shift, the T-case will "pop" back out. if the level is moved to 2wd while under load.



I found that you can force (read: grind) the T-case going into gear. but you can't force the T-case out of gear under a load. This is good.

 

[JasonCzerak]

yeah. So long as you use it. your truck shouldn't be surpised when you do need it.



This is just one examle of why I do 100mph+ every now and again, run 4x4hi on raining roads (no turns). Slam some gears around, Break hard and turn fast.



Infact, every day when I back into my driveway I drop the T-case to 4x4 lo and backup. I take it slow up the goofy incline and I don't even have to slip the clutch at all.



Anyone ever purchase a car from a little old lady, go to drive it, and it falls apart shortly after?

 

[biggy238]

Yeah... . stopping 7k pounds on snow and ice is hard enough without any speed built up.







No new ideas on what i'm hearing? I haven't had time to change the fluid yet... Week after Christmas maybe.

 

[McLaughlin]

This idea may be totally out in left field but do you think it could be associate with the gear the transmission is using? It is the only reason I can think of that it would quiet down above 35.

 

[CSnyder]

I had the same howl at lower speeds and would quiet down over 55 too. It turned out to be my front driveshaft. 3 u-joints at 13 bucks and a ball joint in the driveshaft for 45 bucks and all is quiet now.

Hope this helps, Chris

 

[biggy238]

that's sweet because I know I have serious issues with the front most U joint. I replaced all of them a year ago and am having problems from the front Yoke-Joint fit.