Transfer case stupid question thread

[lio45]

I might as well ask...



Mine sometimes makes a big "crunch" sound when I go from 4LO to 2HI... it pretty much will do it unless I'm on a perfectly flat surface, and in Neutral.

For some reason, I have to be in Park to put it in 4LO (truck has the slushbox). I can't be in Park to put it back in 2HI though, it has to be Neutral. It just won't get in otherwise. Sometimes IIRC it even won't leave 4LO if the truck's weight is resting on the tranny's parking pin. I have to be on a flat surface and then it behaves much better (but still does "crunch" sometimes).

Is that normal? I guess not. And what's the normal procedure for operating the transfer case on an automatic truck? Right now I've found through trial-and-error that the best is to be in Park to go to 4LO, and in Neutral to come back from 4LO, and Neutral as well for switching between 2HI and 4HI. That seems weird...

This is my first 4x4 truck that hasn't got a manual tranny... so please forgive me for sounding stupid, even though the thread's meant for that.

Edited to add: 1995 K1500 6.5TD 4L80-E, so NP241 T-case.

 

[outalne94z71]

trans has to be in neutral to go from 2hi to 4 lo and same the other way around, does not need to be in neutral to go 2hi to 4 hi

it will grind if trans is not in neutral because the input shaft in the case will turn as soon as the case hits neutral and you are trying to continue shifting while the mainshaft is now moving.

 

[1997chevydriver]

2hi to 4 hi to 2hi you can shift while moving

2hi to 4lo to 2hi stopped and in neutral and use one swift fluid motion to shift.

 

[lio45]

Thanks!

So... if it grinds when I shift back into 2HI while the truck is idling, in neutral, on a flat surface... which it often does... then what T-case condition/problem would that tend to indicate?

Also, sometimes I have trouble disengaging the front wheel drive... say I was in 4HI, now the T-case shifter is back in 2HI (done in neutral on flat surface), the orange lighting that indicates front wheel power is turned off, and the truck is undeniably still driving on 4HI! Usually, in those cases, I just try playing with the T-case lever, into neutral, back in 2HI, etc. and eventually it works.

Has anyone heard of such symptoms?

Never had any problems with T-cases in my 4x4 Fords over the years, so I'm still a total newbie as far as T-cases go. They worked well, never any glitch, so I had no particular reason to get interested in T-cases. I'm a very amateur mechanic, so I generally gain knowledge of new things only when they break and I have to fix them...

 

[1993GMCSierra]

I've read that the transfer cases in these can be weak point at some times, so out of curiosity I'm posting this.

I've owned my GMC for 3 years. I've used 4WD maybe 5 times in that span of time. Does the transfer case run all the time, or only if 4WD is selected? I guess I'm just wondering if I never use it, if I have to worry about it breaking and leaving me stranded.

 

[1993GMCSierra]

Hmm...double post.

 

[outalne94z71]

I've read that the transfer cases in these can be weak point at some times, so out of curiosity I'm posting this.

I've owned my GMC for 3 years. I've used 4WD maybe 5 times in that span of time. Does the transfer case run all the time, or only if 4WD is selected? I guess I'm just wondering if I never use it, if I have to worry about it breaking and leaving me stranded.

no it does not completely run full time, it does have the mainshaft and oil pump run full time but the actual 4wd does not run until engaged.

the np241c is a pretty good unit as long as its full of atf you should have few issues, there is a $1.50 clip in the tailshaft that likes to break, especially if you like to downshift, you have the better aluminum shift forks with replaceable nylon pads

 

[1993GMCSierra]

What kind of fluid is recommended in it? I'd like to replace it, as it's likely original. ATF+4? Dexron III?

 

[outalne94z71]

What kind of fluid is recommended in it? I'd like to replace it, as it's likely original. ATF+4? Dexron III?

dextron

 

[Darkrider]

Ok just gotta ask since this thread is mentioning the Borg Warner casses were used in 92+ K3500s. What would be in an '89 K3500?