Chev 4x problem

7

73eldoconvert

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My 97 Tahoe feels like most if not all of the front end is engaged all the time.  The dash indicator is on steady 2hi and it is not locked in 4.  I assume the switch and the feedback come from the T case so it is likely the front axle that is stuck?  I assume this style just unlocks one axle so the spiders just spin?  I remember people talking about an upgrade to this vintage because the original used some sort of heater actuator that were prone to sticking (but not as bad as the previous vacuum ones).  Mine still has the heated ones.  We have a high today of -15*F so I decided not to mess with it further.  I figured it would be best not to make things worse. 

Anybody know what the common failure mode is on these?
 
TJ it usually won't lock into 4x4 if the heater element goes bad. Well at least thats my understanding of the new setups. They make a cable lock to bypass that element and its a manual setup so you know what you have
 
I have a simular problem with my 2003 GMC Z71.  It will work properly 3 or 4 days during the week.  Crank it and it will be in 2 Hi.  Then usually one or two days a week when I crank it to go home it will be in 4 Lo, and I will not have touched anything.  The engine will bog down and almost stall when it tries to shift into second.  After it shifts it will run like normal until I stop and it goes back into first.  If you push the buttons to take it out of 4 Lo nothing will happen.  I tried replacing the switch on the dash but that didn't fix anything.  It was the cheapest part to replace.  The accuator on the transfer case is the only other part and it is $400.  Buying the accuator would not bother me so much if I used 4 wheel drive all of the time, but I probably have not used it 10 times since I have had the truck.  I guess I just a CSOB.

John
 
I decided to take advantage of the 10* heatwave and messed with it a bit.  Found that it is not locking into 4x or if it is its not staying locked. Buttons on the dash respond normally.  It does go into 4 low but I dont get the feeling that it is locked in any better than in hi.  Anyone know how those front axles lock and unlock?  I have been told that they are a split case that can not be worked on while in the truck and getting them out with the body and engine in can be a trick.

Anyone got any ideas or pictures of the thing?  I kinda miss my 3/4 and 1 ton with solid axles and manual hubs. I dont think its going to be warm enough to get anything done in the near future.  Good part is at the moment we have 4 other cars at the house right now, one is the mustang that aint much of a winter car but the others have been running alright so if it has to sit for a while it can.
 
Spent some time looking for/at forums, found several people describing the exact symptoms I have on the same vintage trucks.   

No replies  :cursing:

Most of the 4x boards seem to be hung up on lifting, they dont appear to talk about much else.
 
I'll ask on the k5 board...they're a little nicer than the boys on pirate.....and thats being polite
 
Further info:
Its in the 20's today so I at least got the jack out in the snow and did some more checking.
-Front end off the ground in 2hi, both wheels spin freely with a normal amount of drag, front drive shaft spins free.
-Front end off the ground in 4hi, wheels spin in opposite directions without much more drag than alone, front drive shaft will not move by hand.
-One front wheel off the ground 2hi, wheel spins normal.
-One front wheel off the ground 4hi, wheel rocks back and fourth and I can see drive shaft rocking also. without pushing any buttons I took it for a drive on enough dry pavement to tell that the 4 wheel is not working as it should, that is I can do a 90* turn on wet but not icy pavement without feeling any drag or wheel skip like I normally would.
- the drag and vibration feel is the same in all modes including 4 lo.

What do you guys think?

I talked to a friend and he said that this T case has a electric clutch that acts like a syncro for the shift on the fly feature.  He thinks that this is why I can not turn the front by hand yet it does not appear to be 'locked'.  He thinks that there is broken stuff in the case causing the vibration and drag.  He asked how often it gets run in 4x on fairly dry pavement and I suspect the answer is more than it should, its the wifes car and she is a lead foot that likes the 'safety' of her 4x4.  The good part is at least the T case is not that hard to remove and I can get a warrantied used one from a local yard for $250.  Bad part is that wont fit on the lift in my garage so its going to have to sit untill its warm and dry enough to do it outside.
 
Now that we are into the March/ Apr weather I got the Tahoe back on the road again.  I figured the problem had to be in the front end so I took it all apart.  This is the style where the front axles are just like the old eldos, held on to flanges with 6 bolts.  They are 15MM.  Axle nuts are 36MM.  All you need to remove to get them out is the tire and the sway bar end links.  With the rotors off its easy to check the wheel bearings.  No problems there decided to take it for a quick drive without the front shafts installed, same problem.  Put the front back together and pulled the rear shaft.  AFter beating it out of the rear yoke I took it for a ride in 4x and all was nice and normal truck like.  The top off of a PB Blaster can fits perfectly over the rear output shaft of the transfer case to keep the fluid in.  After getting home and having a look at the rear shaft I discovered that the rear u joint only moves if you hit it real hard with a hammer!  Even the guy at the shop said he had never seen one that stuck before.  Also found there is a shop near me that got the shaft rebuilt and balanced in around 3 hours for $120.  They also had the spider gear set I had been looking all over the world for.
 
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