MsDee

My 4 wheel drive on my '95 Chevy Suburban prevents me from driving. I think it is my transfer case, but someone keep telling my "mechanic" it is my transmission. Is it possible to just disconnect the 4 wheel drive?

SWHouston

Could you give a bit more detail about it ?

Describe what happens when you put it in gear with the engine running.
Do you see/feel any of the Wheels try to rotate ?
Are there any noises/clunks or changes in the idle ?
Will it roll back and forth when you put your shifter in neutral ?
Will it roll back and forth, when the shifter is in Drive or Reverse with the engine running ?
Do you know if your Emergency Brake is completely released ? *
Have you operated it in 4WD previously, Hi or Lo, or both ?
Have you checked the Fluid Level in the transmission ?
Is there a "Check Engine" light on, have you had a Diagnostic Code Check done ?
Are there Buttons on the Dashboard which control 2WD & 4WD ?
If so, could you have possibly electronically put the transmission in Neutral ?
If you have any Buttons, are there any lights associated with those buttons, blinking or on steady, and if so, which Button(s) ?
Have you allowed a Child or other mischievous person to be alone in the vehicle, with the Key in the ignition ? *

(* = please don't take offense to the above questions, but "meddling" could be the cause of the problem)

To answer your question...
Generally no, any disconnection wouldn't help.

Is this "someone" who is advising you, familiar with how to operate the 4WD functions ?
Is your Mechanic at a Dealership ?
Have you gotten a second opinion from another qualified (preferably GM) Mechanic ?

Sorry about so many questions, but they're necessary given we can't see/test the vehicle.

cleveland63b

agreed cant even begin to guess without more info

MsDee

Thank you for answering.
When I put it in gear with the engine running it will now move and I hear a squeal like when you turn the ignition and the vehicle is already started. The floor lever(in the beginning)would slip in neutral and my truck would stop. Then the sound got worst and I would gear a loud boom and the truck would only drive in 4L and after a while would only move in reverse while in 4L. Truck sat up for a month after that and now it starts but, it doesn't move at all. There is no button on the dashboard, shifter in neutral truck will roll either way.
the emergency break is completely released
Used to drive truck in 2H and 4H in winter but switched to 2WD when moved to Florida.
No meddling.
sent my truck to transmission shop, they did not do a diagnostic check but took the drive shaft apart from the rear differential and they charged me $90 to tell me nothing.
I will replace the CV axles and trans filter.
Love the questions. Gives me way more help than mechanic. Thank you

MsDee

The mechanic is licensed but doesn't really know anything about 4WD.
Disconnecting the 4WD was my thought.
Haven't driven my truck since Feb.
Chevy dealership repair shop mechanic wants $$$$ to fix the problem.
'95 transmission and trans case was repaired
'99 rear differential was replaced.

SWHouston

Dee,
Let me see if I understand this...
You have an Automatic Transmission, and
a Manual 4WD (leavers on the Floorboard) right ?
(if it happens to be a Manual Transmission, it won't change my answer below)

Here's what I think happened...
At some point, someone attempted to change the range from 4Hi to 4Lo, and it didn't get completely changed, (therefore sticking it in BOTH ranges at the same time) which locked the axels up. This may have also been caused by a mechanical failure in the shifting mechanism.

As the vehicle was attempted to be moved/driven, it cracked/broke one of the slider gears in the Transfer Case, and with that broken, you're not going to be able to drive it*, and that's the cause of the noise.

So, (if I'm right) it's not the Transmission, but the Transfer Case which needs repair.

* = Exception...
1) You might be able to remove the Driveshaft to the Rear Axel, somehow lock the Driveshaft Yoke into the Transfer Case and drive it that way, just by engaging the Front Axel (ie 4WD Hi mode). For all general purposes, you would be forcing a change from Rear Wheel Drive, to Front Wheel Drive.
This really would be a pain in the Tush to do, since the Front Wheels are locked together, and, if the wrong slider (or more than one) is broken, even this wouldn't be possible.

You need to have your vehicle Professionally Repaired...
Sometimes, it's just easier and cheaper, if you have a Rebuilt Transfer Case installed. Those usually go for about $800-$1000 +labor. This can usually be done by a regular but reasonably qualified Mechanic.

If you choose to have the existing Transfer Case Rebuilt...
Then you should go do a Dealer, or a Differential/4WD Specialty Shop, and have it done by a specially qualified Mechanic. That'll probably equate to a 30-40% increase in the cost of the repair.

Terms...
Transfer Case:
Is a separate (2nd) Transmission, which when connected in addition to and behind the regular transmission, changes the Gear Ratio from Hi (normal driving) to Lo (a very powerful pulling mode).
Slider Gear:
A Gear which (via a leaver accessible to the Driver) is slid along a shaft (inside the Transfer Case), changing the engagement of one set of gears to another separate set. In this case, from lower ratio gears to higher.

So you were right...
You were calling the problem a 4 Wheel Drive problem, and that is true, except that a proper term for it, would be a Transfer Case problem.

Same thing...

MsDee

Thank you so very much. The information you provided helped! You gave me more insight in 1 day than I have gotten in the eight years that I have had my vehicle.
Bless You!

SWHouston

You're very welcome Dee,

But remember, this site is here for us to share our knowledge, please visit again.

No telling, at some point, you may be able to help someone out.

Have a good Day !

S.W.