'99 Suburban 4X4 Components--What Next??

[overlander64]

I special ordered my '99 GMC K2500 Suburban new and took delivery on April 21, 1998. In the years and nearly 200,000 miles since, it has been very reliable with one exception. The four wheel drive mechanism has been nothing but trouble -- actually worse than the '95 Chevy with manual 4x4 that I traded on the Suburban because it was continually getting stuck in four wheel drive and it took a trip to the dealer to get back into two wheel drive high. The following maladies have been experienced by the 4x4 mechanicals:

• Routinely, starting at 34,000 miles, the electronic circuit board that controls the four wheel drive transfer case began to predictably fail at 12,000 to 15,000 mile intervals. When it failed with 12,000 or fewer miles, GM replaced it under warranty, but when the mileage since the last replacement exceeded 12,000 miles it was my expense to the tune of $750.00. This part has been replaced 12 times, and I have paid for it six of the twelve time.
• The transfer case has had to have new seals installed at 85,000 miles and again at 170,000 miles.
• The clincher was today, when my mechanic called to tell me that the clanking that I had begun to hear when the Suburban was moving had a cause in the transfer case. The diagnosis is a failing chain drive mechanism that if it fails while the truck is being driven may cause a loss of control. Estimate to repair is between $1,200 and $4,000 depending upon whether it is just the one gear that needs to be replaced or if a new Good Wrench replacement transfer case will be needed.
  • I hadn't used the four wheel drive feature since the truck hit 180,000 miles since I did not want to replace the circuit board any more -- my assumption was that when it failed it would be stuck in two wheel drive high which is fine with me.
  • Now the transfer case rears its ugliness and wants to be replaced. My thought has been:
    • Would it not be possible to simply remove the transfer case and not replace the assembly?
    • Or would it be possible to permanently disable the four wheel drive such that replacing the transfer case wouldn't be necessary?
      • I know that I would still have the front differential, but is there some reason that it must be connected to the transfer case?

I have been thorough with my maintenance, and do not want to trade the Suburban as it has met my every requirement with high reliability other than the horrible four wheel drive mechanism. I don't care whether I have functioning four wheel drive, and don't expect that it would make much difference in trade-in value given the age and high mileage on the odometer. I do know one thing, if I do replace the Suburban, its replacement will be a big-block Suburban that positively will not have four wheel dirve!

I am expecting, but hoping not to hear, that the only way to solve the problem is to replace the transfer case -- and given the mileage I would expect that the Good Wrench replacement will likely be needed.

Kevin

[overlander63]

Kevin, if your Suburban was sitting in my shop, and you told me what you did above, I would:
1- Remove the front and rear driveshafts

2- Remove the transfer case

3-Disassemble the transfer case, and remove the chain

4-Reassemble the transfer case, without the chain

5-Reinstall the transfer case, and rear driveshaft.

6- Make sure nothing leaked, and the wiring for the 4WD was disconnected from the transfer case

7- Remind you that you now own a 2WD Suburban, and tell you "Happy Motoring".

8- Collect a check for about $800 for my labor taking everything apart and removing the broken parts.

[overlander64]

Greetings Terry!

Originally Posted by overlander63

Kevin, if your Suburban was sitting in my shop, and you told me what you did above, I would:
1- Remove the front and rear driveshafts

2- Remove the transfer case

3-Disassemble the transfer case, and remove the chain

4-Reassemble the transfer case, without the chain

5-Reinstall the transfer case, and rear driveshaft.

6- Make sure nothing leaked, and the wiring for the 4WD was disconnected from the transfer case

7- Remind you that you now own a 2WD Suburban, and tell you "Happy Motoring".

8- Collect a check for about $800 for my labor taking everything apart and removing the broken parts.

I hope to convince my mechanic to follow what you suggest. If this problem can be resolved, it still looks like I may be able to get around 300,000 miles before the motor and transmission are likely to need replacement.

Kevin

P.S.: I don't expect that my mechanic will get too close to your figure for labor as his shop rate is $100/hour for heavy mechanical work. Even $1,500 would be more palatable than replacing the transfer case.

[overlander63]

Plan "B" would be a used transfer case. There may be some slight flaw in yours that is within tolerances, but is gradually destroying itself.

Used 1998 Chevrolet / Chevy K2500 Suburban Transfer Case Assembly1998 Chevrolet / Chevy K2500 Suburban
V-8, Gas/Injection, Automatic-OD, 4x4Transfer Case Assembly
350
4L80 trans. NP8. Auto 4x4. Dash switchHaslett, Michigan 48840

[rangebowdrie]

Man,,,,, that is a bad experence, am I correct to assume that this is the "push button" kind of set-up?
I know that I have seen 'Burbs of the '99, to '02?, I think, that had manual levers sticking out of the floor. This is how it should be.
Perhaps one could be installed?

[ROBERTSUNRUS]

Hi, I don't know your mechanical abilities, but most transfer cases have very few parts inside and are really simple. You may want to take it out and apart yourself. Buy a book or make copies from book at the library. And like Terry said, [no longer at Inland RV] remove the chain and lock it in two wheel drive mode.

[Kevin245]

Originally Posted by overlander63

Kevin, if your Suburban was sitting in my shop, and you told me what you did above, I would:
1- Remove the front and rear driveshafts

2- Remove the transfer case

3-Disassemble the transfer case, and remove the chain

4-Reassemble the transfer case, without the chain

5-Reinstall the transfer case, and rear driveshaft.

6- Make sure nothing leaked, and the wiring for the 4WD was disconnected from the transfer case

7- Remind you that you now own a 2WD Suburban, and tell you "Happy Motoring".

8- Collect a check for about $800 for my labor taking everything apart and removing the broken parts.

If I were in your driver's seat this is exactly what I would attempt to do. While trucks and SUV's are (IMHO) worth putting cash into even at higher mileages, it is still a tough pill to swallow given the amount of trouble you've experienced with the 4WD system.

I have a 97 F150 with over 300K miles. I'd drive it anywhere, and wouldn't hesitate to drop money into it for repairs, but when you get over a certain amount ($2K for me) I have to set back and really look at the ROI.

Best of luck and may things go your way.

Kevin

[Road Ruler]

Originally Posted by overlander64

• Routinely, starting at 34,000 miles, the electronic circuit board that controls the four wheel drive transfer case began to predictably fail at 12,000 to 15,000 mile intervals. When it failed with 12,000 or fewer miles, GM replaced it under warranty, but when the mileage since the last replacement exceeded 12,000 miles it was my expense to the tune of $750.00. This part has been replaced 12 times, and I have paid for it six of the twelve time.

Kevin

For 30 years I was a service tech for the major computer company (HAL).

Many times these types of board issues would show up. Although the board keeps failing the problem is more than likely external to the board. Could be a faulty/shorting cable, connection, or fleeting voltage or static build up. Also moisture in the wrong place can cause these kinds of failures. They can be very time consuming and costly to diagnosis. A top notch tech is needed to find the problem but the quick fix is always to replace the board. It is bad luck your vehicle has this bug.

[62bam]

You've got me worried now. We have a 99, 4x4, 3/4 ton Sub. with 43k one owner miles. The only issue we have ever had was with brakes, and has been corrected. We just use it for trailer pulling in the summer months. In the winter months, we lesson our insurance and store it in a heated building. Here's the deal....Do I keep it and face possible big repair costs (like mentioned above)....or sell it and buy something newer?....Thanks.

[overlander64]

Greetings 62 bam!

Originally Posted by 62bam

You've got me worried now. We have a 99, 4x4, 3/4 ton Sub. with 43k one owner miles. The only issue we have ever had was with brakes, and has been corrected. We just use it for trailer pulling in the summer months. In the winter months, we lesson our insurance and store it in a heated building. Here's the deal....Do I keep it and face possible big repair costs (like mentioned above)....or sell it and buy something newer?....Thanks.

Your Suburban may have a different 4x4 system than mine. If yours is a Chevrolet, the system that I have on mine was optional. The system on mine is the dash-mounted push-button controls referred to as Automatic Four Wheel Drive. The system was either standard on the GMC or part of a package on mine -- I don't remember which. It also seems that there were only two extremes with this system -- you either lucked out and got one that is remarkably reliable requiring few if any repairs -- or it was like mine -- broken down every 12,000 to 15,000 miles. I don't know that I would be overly concerned if you haven't had a problem at6 43,000 miles as it seems the first breakdown usually happens before 40,000 miles. I know of two other GMC Suburban owners who have been experience these same issues -- but they are at about half the mileage on mine.

Kevin

[tlavergne]

I have the same vehicle with 104,000. No problems with 4 wheel drive system. However I had a front axle that had to be replaced and the rocker arms in the heads had to be replaced at 80,000 miles. Those 2 repairs were about $3000 total. It runs great but every time I take it out on the road I worry about another odd, expensive repair that will leave me by the roadside.
Tom

[62bam]

Thanks for the info. guys. I should have mentioned our 99 is a Chev with a dash push button 4x4. Ron

[bobfowler]

My '99 Burb is a 1500 4X4 with the push button system. Just went over 116,000 miles and, so far, the xfer case is fine. I bought it almost 2 years ago with about 70K miles on it. The FIRST thing I did was take it to my mechanic who flushed the tranny, Xfer case, and differentials. I change those fluids every 20K whether they need it or not. Overkill? Maybe. But I take no chances...

[ROBERTSUNRUS]

Originally Posted by 62bam

You've got me worried now. We have a 99, 4x4, 3/4 ton Sub. with 43k one owner miles. The only issue we have ever had was with brakes, and has been corrected. We just use it for trailer pulling in the summer months. In the winter months, we lesson our insurance and store it in a heated building. Here's the deal....Do I keep it and face possible big repair costs (like mentioned above)....or sell it and buy something newer?....Thanks.

Hi, Mom said, "never worry about anything before it happens." If it breaks and you want a new vehicle, buy one. If it doesn't break, keep going and get your money's worth.

[Action]

Isn't there a drive shaft from the case to the front differential that can be removed?

It would be cheap and easy as long as there isn't a slip joint into the transfer case. And cheap and easy is a rare combo these days!


Action

[CGStitt]

Hi, I also have a 99 4X4 Suburban, only a 1/2 ton which I'm looking to replace with something more suited to towing our 31ft Excella.

Anyway a little over a year ago I got a service 4WD system light and unfortunately decided to shift out of 2 wheel high to 4 wheel high and then to 4 wheel low where I got stuck. I did some research online and read that the push button 4 WD system was known to have a poorly soldered switch. I removed the switch and re-soldered the connections on the back of the switch. The light went out and I've been able to shift into and out of 4WD for the last year without any problems.

Might be worth a try, good luck