I have had similar problems with two Chevy Astro Vans (1997 and 1999)... i.e. a grumbling noise in the front-end when making slow, tight turns and a few rapid clunks in the rear when accelerating from a stop especially when going up hills. The problem was more pronounced when the car was hot since I think the transfer case fluid tends to lose it's viscosity at higher temperatures. The dealer's remedy which worked for my 1999 van at 6,000 miles and, hopefully, again at 43,000 (we'll see for how long) was to replace the transfer case fluid with 3 quarts of a blue synthetic lubricant made by GM called, Auto-Trak II Transfer Case Fluid. The dealer's price for this fluid after the warranty expired was about $33 per quart plus labor or about $170 in total. They did the replacement for free at 6,000 miles. I would recommend you flush and replace the transfer case fluid as soon as you suspect this problem rather then waiting for a bigger repair bill.
I have a 99 Safari. Soon after purchasing it new the "binding" while turning at slow speeds problem appeared. I took it in for service and the dealer just happened to mention to me that there had been a service recall on that. I don't think GM had ever notified me of any such recall. Of course the "fix" was simply to change the transfer case fluid. A band-aid fix at best. I have had this service repeated (at my cost) every 50,000 or so.
I just took it in yesterday for another flushing and the dealer said that they noticed another problem. This always scares me... is it really a prob or are they just trying to jack the bill? Anyway, he said they noticed that the front axle is "always engaged". I guess its only supposed to engage fully when power is needed. This doesn't pose any noticeable problem when driving the van, but I guess I'll tell them to fix it anyway. I can only imagine what this is going to cost me.
We have a 2001 Chevrolet Astro AWD and have had no end of problems. We owned a 1999 GMC Safari previous to this and were very happy with it. The Safari was a standard 2WD model and we wanted to upgrade to AWD. What a mistake. From the beginning we noticed a shudder in the driveline when turning right or left, most often after exiting a highway. The dealer told us this was normal. On a long trip, we then noticed oil on the rear window. It turns out we were blowing fluid out of the AWD transfer case when it got hot. We were on a long trip so the dealer added fluid and we continued on. We limped home by adding fluid every time we noticed a leak. Our local dealer replaced the rear seal. This lasted about a year and the same thing happened again. This time they replaced the rear seal and the rear output shaft on the AWD transfer case. The thing I noticed the most is that when the AWD transfer case was topped up, the shudder that they claimed was normal went away. Our vehicle has had the blue AutoTrak II fluid from the start so that was not the issue.
The fluid they use in the AWD transfer case is not just a lubricant, it is part of the viscous clutch design. It does
not have characteristics of a typical lubricant. One thing I have noticed is that it washes off with water quite readily.
You could have a small leak and not notice it. I mention this because I was nursing a leak on the box. I have now carried a couple quarts of the magic blue fluid and a small pump with me. I have had a hard time finding it in remote areas. When I noticed the shudder, I would check the fluid level in the top plug and add it if needed. The hope is that the replacement of the rear shaft finally fixed the leak.
On a very recent trip, we started smelling a strange burning odor. We kept pulling over and could not determine the cause.
After about 100 miles, we turned a corner and I noticed a shudder again. I feared we were having AWD problems again, but this time there was no leak. A little farther down the road, we pulled in to a gas station and the vehicle bucked violently when we turned. We were pulling a small pop-up trailer, 2500 Lbs. (the reason we bought this vehicle in the first place). I dropped the trailer and tried to determine what was wrong. I could drive straight, but not turn. I could see the rear wheels stuttering in the gravel. I suspected the rear differential this time. After it cooled down, it was drivable so we got it to a private auto service facility.
They pulled the cover on the rear end and the smell was terrible. The vehicle has a limited slip rear differential and it seems the clutches were sticking. The GM dealer told the service facility that it just sounded like lubricant failure and to replace it. They did and we went on our way.
After 400 miles, the same thing. We limped in to a dealer and we were stuck for 10 days. We ended up burning up the entire rear differential. They replaced everything short of the case and axle shafts. This occurred at 33,000 miles.
This vehicle has been serviced under warranty so many times I have lost count. We have had problems with power windows, power mirrors, idler arms, oil lines, terrible wind noise in the front doors. The list goes on. On the trip home after the differential failure, the radio quit working. With 8 days left on the warranty, I guess they get to see it again.
I have a 2000 safari. Experienced transfer case problems with rear wheels chirping when turning corners at slow speeds. Tried fluid change, no luck. Dealer changed encoder motor on transfer case at 600 dollars. Problem went away.
23rd Sept 2003
I have a 2000 Astro AWD van the van has always had a little stutter at low speed on full lock (parking)
It finally got so bad I took it to the dealer who said it is a common problem with both the diff and the transfer case clutches. So $650.00 later after a flush and new oil the problem is gone, but reading the comments of other owners I have serious doubts about this van, and will have to think twice before buying another GM product.
So far from new we have had new struts on the back door. New power door actuators. (2).
It seems that this transmission problem is widespread and not what buyers expect from a "heavy duty" truck. GM needs to step up to the plate and do what is necessary to live up to their ads before they involved in lawsuits to force them.
I have contacted GM and will update this site when I get an answer from them on what they are prepared to do.
I just bought a used 1998 GMC Safari AWD. I wish I had to see this post before I bought it. I only had it for a week so far... I guess I'm going to be sorry for this buy. So far after 1 week... I am experiencing grinding noises when turning in reverse as well as the delayed engagement or bucking when accelerating from a stop.
Is there anywhere to get a list of recalls?
Booyeah29@yahoo.com.
I have a 2000 GMC Jimmy 4x4, which ironically, I have the same exact problems as you folks. Whenever I turn corners, it binds real bad, even in 2 HI. Now I know that you cannot take your vans out of AWD, my transfer case is supposedly "Automatic". Well let me just say this, I am going to the dealership Friday for the binding in 2HI, which feels like its in 4HI or 4LO, and if they pull that changing fluid junk on me theres gonna be some ugliness going on!! My truck only has 48,000 miles on it and THANK GOD I purchased the 6 year 100,000 miles warranty with $0 deductible. GM is going to regret that because the warranty cost me about $2300 when I bought the truck and I've already used about $5000 in warranty repairs already as of now. My radio went out, my power window motor was bad the day I picked it up from the dealer. I smell some litigation here...
We own a 1999 Chev Astro Van AWD and have had all the same problems mentioned by others related to grinding noises
when turning, which the dealer supposedly fixed as a service bulletin item. We have also had many other problems with this van related to leaky seals, many brake replacements, electrical problems (door locks, windows, rear window washer going on when you turn on blinkers!) etc. Now, at 83,000 miles it looks as if the transmission just went out. It's going in the shop today for definitive diagnosis, but it won't go in reverse and goes from 1st to 3rd gear, skipping 2nd. We should have traded it in when we thought about it last year. Now it looks like we're in for a pricey transmission repair. I will never again buy a Chevrolet vehicle. I too am interested in any comments related to Chevy admitting to their accountability for transmission / AWD problems.
In August of 2001 I bought a 1998 Safari SLX AWD and have experienced the harsh shifting between first and second gear as described in an earlier comment someone else posted in June 2003. GMC mechanics have given me more than one reason for this at more than one time. I had work done earlier by a GMC dealer when I was told it was a bad sensor, but that did not stop the problem and cost me money. The latest explanation involved a sticky valve and I was informed it was not unusual on this particular transmission. It is definitely worse after thirty minutes of driving and in the warmer weather. I intend to live with it until it totally breaks as the last repair was costly and accomplished nothing... for me. The only other problem is a driver's side electric window that does not want to go back up immediately. I was informed a new motor is required. I am sure that would fix it, but I doubt that a whole motor is necessary. I'll live with this problem also... Until I sell the van. The only other annoyance is that the screws and other hardware used to affix interior trim keep coming loose. The van does carry a big load of lumber nicely, though, with the dutch door arrangement on the rear. That works. After reading here and other places about the Safari, I believe I am relatively fortunate.
I would like to add to this interesting thread, I have a 1998 GMC Safari Van 2 wheel drive, it was a Rental vehicle. We purchased the vehicle with 38,000 miles on it, at 51,000 we had a hard shift from 1st to 2nd. we had the Transmission serviced in Idaho, We live in VA BTW. we returned and took it in under warranty, they rebuilt or replaced the transmission, said 2 or 3 bands broken and Valve I believe. Next Problem was Electric Motor in Driver side window, sounds familiar, then the Passenger window motor went out, Fuel Pump went out prior to the windows. I now have a Whining (Very Loud) at 91,000 miles. Front end not too many problems. Now what to do... I think if the transmission gets replaced it will be time to Sell it, too bad because the body is in great shape, but I am not going through the transmission a 3rd time. If I fix it and keep it I think a Transmission cooler may be a wise decision, we pull a Coleman Pop Up camper with it for Vacations. Next Time we will purchase a suburban or something with a truck chassis, I still prefer GM over Ford due to body styles. Just my 2 cents. Geklr@yahoo.com.
I have all of the same problems when is gm going to finally admit to and correct this problem.
Well it has been a year and $1000 dollars later after having my 1998 Safari AWD SLT in garages including the dealer and even the dealer replacing my front drive shaft unneedingly and I have found and fixed the grinding crunching snapping noise from under my van myself. It cost me nothing to do this job myself. It turns out that the noise came from a loose bolt on the front differential mount. Yes...that's it. The noise was unbearable and I could feel it up through the drivers seat. It was hard to find listening by ear, but I found it. I dangerously had someone hold the brake and shift from drive and reverse while I got under the vehicle and looked and listened around. You wouldn't know, but the front end was going to fall out. It was simply the bolt that goes through the differential mount to the chassis in the front of the van on the driver's side. I got about three turns on the bolt and voila the noise is gone. I'm so happy. Now why couldn't the dealer find that after having it for a full day and replacing the drive shaft and why couldn't the other garages find it. It took me 45 minutes. The next step for one garage was to take apart the transfer case which would have costed a fortune.
Anyway off to fix the next problem... the rear heat.
Booyeah29@yahoo.com.
OK just an FYI... I have found my problem with the rear heat. I did some looking and found the Heater Control Valve just behind the AC accumulator on the passenger side under the hood. Connected to the Heater Control Valve is a Heater Control Valve Solenoid. It just clips on the wall above the control valve. This solenoid has an electrical connection so that when the rear heater switch is turned on and off it switches on and off the solenoid which in turn switches on and off a vaccuum also connected from the solenoid to the valve. The solenoid has 2 vaccuum connections (top / bottom). Disconnect the vaccuum hose from the top of the solenoid and the vaccuum hose from the control valve as well. Plug the vaccuum hose which was disconnected from the top of the solenoid directly into the valve, therefore bypassing the solenoid. Note that this will give a constant flow of coolant the the rear heater core because the valve will always be open because this vaccuum hose has a constant suction. This vaccuum hose from the top of the solenoid is coming from a tee directly on the vaccuum line therefore it has a constant suction. That is why when hooked up directly to the valve, the valve will be open at all times. The solenoid is not working because the bottom hose has no suction when the rear heater is turned on therefore supposed to turn on the solenoid opening the solenoid vaccuum.
Hope that makes sense...lol
booyeah29@yahoo.com.
I have a GMC Safari SLE. After a 30 minutes of driving, my transmission starts to shift hard, and gets worst on hot days. Someone recommended an oil change. I don't believe in changing the transmission oil. Has anyone had this problem? What do you recommend?
I have a 2000 Safari 2 wheel drive and I notice this hum at the rear end. I don't know if it could be a bearing. How can I tell without taking the rear end apart?
Stan.