4wd Problems

andy702252

Original poster
Member
Dec 22, 2011
76
Im hoping Roadie will chim in on this thread. So here's the deal. I was told that the problem with my 4wd may be the tccm. Well it was to some extinct. I replaced the tccm and now my lights on the selector knob has came back on but it will not change modes. It only makes a whining sounds. Someone help please.
 

navigator

Member
Dec 3, 2011
504
if you hear things changing, the normal sounds you expect when switching to 4WD then likely your problem is in the splined disconnect.
Due to poor engineering the disconnect is not an easily maintained system and the grease gunks up and eventually the internals fail.
Do a search on "disconnect" and you should have plenty of reading material.
 

navigator

Member
Dec 3, 2011
504
I've never had to do the fix myself yet, just read a lot of threads on it.
If you are handy with a wrench I don't think it as hard as much as it is time consuming.
It's not like setting backlash etc with gears or timing on an engine. The hard part from what I have read is stuff doesn't always cooperate coming apart.
Sometimes getting the axle out can be a pain.
Sometimes the disconnect gets seized in place and can be a pain to remove.
Some folks end up breaking the disconnect housing getting it off.


If you have a spare vehicle you can tear into it and only order/replace the worn parts (if that is the issue). If you don't have a spare vehicle you almost have to order the ATP aftermarket and have it on hand.


Even if that isn't it, it is a good time to open it up and clean/re-grease everything.
A lot of folks agree that while you have it apart to replace the collar with one from an AWD version so you don't have to worry about that shift fork wearing out/breaking.
 

andy702252

Original poster
Member
Dec 22, 2011
76
Okay here is an update to the exact condition of my trucks 4wd. The selector light stays solid on 2HI, does not even light up when I select AWD and on 4HI and 4LO it will blink but not engage. Somebody help!!!
 

Sparky

Member
Dec 4, 2011
12,927
When it blinks do you hear the appropriate two noises, or just one? It continues to blink constantly or does it "time out" and revert to 2HI?

Was the TCCM a known good one? Could be defective. However it is also possible that your switch is messing up (not all that uncommon for the older switches).
 

andy702252

Original poster
Member
Dec 22, 2011
76
before I changed my tccm my switch did not even light up, after I changed it the lights came back on.
 

Sparky

Member
Dec 4, 2011
12,927
OK, doesn't mean the TCCM is totally working properly. What about the other stuff?
Also did it work normally right up until your old TCCM kicked the bucket?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Sorry I was in Wisconsin for my brother's wedding.

If you have a new TCCM, and your switch doesn't even recognize that you move it from 2HI to A4WD, then the switch is an immediate suspect. They redesigned it in 2005 for increased reliability, and they're relatively cheap even at your local dealer.

You can also run it CW and CCW 100 times or so to try to clean off the contacts.

Once you get the switch to attempt to change modes, then we can deal with the functionality of the front axle disconnect and the transfer case encoder motor.

Has the transfer case fluid been changed religiously every 50K?

When you turn the mode switch from 2HI to 4HI, can you hear EITHER of the two motor sounds you're supposed to?
 

andy702252

Original poster
Member
Dec 22, 2011
76
Thanks roadie, will do on Friday, have a day at the beach planned tomorrow. I can always count on you.
 

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