Failing automatic transmission or something else?

Status
Not open for further replies.
Joined
Apr 29, 2012
Messages
205
Location
East Tennessee
I'm trying to figure out if I have a transmission issue with my van or I need to look somewhere else. Most of the cars I've owned have been manuals. I'm trying to figure out if my van's automatic is about to [censored] out or if a simple filter change or possibly a transmission flush is in need. According to Wikipedia, the transmission in my 1998 Chevrolet 1500 Express van (5.7l 1/2 ton) 4 speed automatic is a 4L60e. Does that sounds correct? A mechanic at the Chevrolet dealership actually told me these transmissions were robust but GM front wheel drive automatics were junk because they won't last more than 100,000 miles. This van has 143,000+ miles on it. I bought this van from my father and have no idea if he ever had the transmission filter changed in it. I'm not real sure if this is a transmission issue but yesterday my wife and I were on a day trip (about 100 miles) and we stopped to get something to eat. When I got back in the van and proceeded to pull out on a slight incline, the van started making this jerking sensation at very low speeds. Above 5 or 10 mph, it smoothed out. This tended to happen for about 5 miles when pulling out at every red light. At one point at a red light I proceeded to change lanes and gave it some extra gas to get around a slow moving vehicle and the van seemed like it was sluggish then all of a sudden picked up speed. The problem eventually went away. We made a few more stops before reaching the interstate. At one point I checked the transmission fluid with the engine running in park. The fluid was a bit dark. Not a good sign from what I once saw on my wife's Buick shortly before the transmission [censored] out. After may 50 miles, we came to a red light. I pulled out and the van seemed to be OK but then it made this slight thump. Like something had slipped. This same thump seemed awfully familiar. If you have read my previous posts about the sprague clutch on the 4 speed gear on my Trabant 601 not engaging. Since sprag clutches are also used in automatic transmissions. Just based on my experience with failing automatics, they usually don't give any warning when the fail. Once they start slipping, they self destruct rather quickly. My father's 1994 Plymouth minivan made it 1/2 mile after the transmission started to slip. My wife's Buick said it maybe 60 miles. This van made it 100 miles home. So based on that, the transmission is probably saveable. If an automatic transmission has "issues" does it act as the same as a manual transmission with a worn clutch? So when you pull out does the engine rev up but nothing happens? That's not what I am experiencing. Or does it jerk until the vehicle starts moving? That is what I am experiencing. Does it make it a clunk after pulling out from a red light? Once. I had a 2006 Ford Explorer that developed torque converter shudder. Hard to explain but it basically felt like the transmission could not make up it's mind what gear it wanted to stay in. And the RPMs would "lope" every 5 seconds if set on cruise control. I had the dealership give the transmission an enema. I don't know how this machine works but it seemed to do the trick. I've heard mixed opinions about flushing automatics. Some people say flushing the transmission does more harm than good. That it breaks up build up and get's into the parts. Or it will blow the seals out of the transmission. I've even heard some people say simply changing the filter and replacing the fluid will cause it to die an early death. That's stupid. My guess is in these situations, the transmission was probably on it's last leg to anyway and no amount of work was going to save it. So is what I am describing sounds like a transmission issue or something else? Worn U-joints in the driveshaft perhaps? Fuel injection issue? Like I said, I've owned more cars with manual gearboxes than automatics and not really sure when an automatic is about the [censored] out.
 
Joined
Aug 18, 2004
Messages
3,392
Location
Raleigh ,NC
These units shifts are controlled by solenoids. Not uncommon for people to change them as a set through the side cover. As for the fluid I would change it and use Dexron vi to refill.
 
Joined
Aug 19, 2010
Messages
10,833
Location
Champlain/Hudson Valley
You are asking about the 4L60E? The same trannie was in a 2001 Camaro I sold for neighbors. The manual said to service that unit every 30,000 miles. I read that bit over and over to make sure I got it right. Drop the pan, change the filter and refill. Add the LubeGard red. Take it from there. I would think the unit is well worth rebuilding if it comes to that.
 
Joined
Jun 24, 2004
Messages
14,505
Location
Top of Virginia
Originally Posted By: TurboFiat124
A mechanic at the Chevrolet dealership actually told me these transmissions were robust but GM front wheel drive automatics were junk because they won't last more than 100,000 miles.
Both of those are gross generalizations. I think some years of the 4L60-E had problems with sun gears or torque converters, right? Seems to be an issue that can come up on Astros and S-10s of this era also. The mechanic at the Chevy dealership obviously has never come across a 4T80-E -- the FWD transmission used in GM's large cars with the Northstar series engines. It's extremely robust and mechanical failure (at nearly any mileage) is extremely rare.
 
Joined
Dec 7, 2015
Messages
405
Location
Ohio
We had a band snap in our Grand Prix around ~165K. The "rebuild guy" said he has only had 4 other occasions where this has happened. The car wouldn't shift out of second. The cause was more than likely parking on a slope in the driveway w/o the parking brake. The transmission shop said he rebuilds these transmissions often and that most GM transmissions are trash. Ironically, he drove a similar Grand Prix.
 
Last edited:
Joined
Aug 12, 2015
Messages
3,457
Location
NC
If the pump is not pumping fluid, or is starving for fluid, it will indeed slip when you are giving it the gas. Kind of like when a manual clutch is slipping. My Olds blew a trans hose from the radiator, and it started slipping before I found a safe place on the side of the road. That's been about 15 months ago, and the transmission is still working fine. Since I lost most of the fluid cause of the hose leak, I had it towed, and had the shop drop the pan, and change the filter too. The fluid that was in it was really old and brownish in color, but it was not burnt, and this color is normal according to my GM manual.
 
Joined
Oct 23, 2005
Messages
7,998
A few years ago an acquaintance of mine had transmission issues, did a pan drop and refill. Issues came back after 5k. He repeated this process 3 more times over 15000 miles, and following that the transmission was fine for another 150k miles. They're designed to run on fresh fluid, and the fluid will eventually wear out. I'd recommend trying fresh fluid, but NOT doing any kind of flush. It could of course be something else, but...
 
Joined
May 18, 2012
Messages
7,869
Location
Baltimore, Maryland, USA
I also think you need to change the transmission fluid and filter. The vintage 1995 automatic transmission in my Ford Escort has around 237K miles on it and I drove it to work this morning just fine. I didn't bother do change the fluid and filter until around 165K - 180K miles (I forget exactly).
 
Joined
Mar 31, 2010
Messages
6,067
Location
Iowa
A shudder or vibration pulling away from a stop that smooths out with speed? I'd say it sounds like a misfire. Check plugs, wires, cap and rotor. Pay particular action to the coil wire. I'd be willing to bet its burnt through.
 

JTK

Joined
Aug 14, 2003
Messages
14,914
Location
Buffalo, NY
~140K is a fairly average lifespan, especially in a full sized van application that has never had a fluid change, plus it's ~18yrs old! I know some 4L60Es had sun/reaction shell issues for some year ranges, but that's a all-out failure. The 4L60E is a pretty good, mass produced trans. I would do a pan drop and filter change and then do some pump or suck out fluid exchanges if it improves from the pan drop and filter change.
 
Joined
Sep 6, 2007
Messages
2,184
Location
TX, USA
There are trans shop that specialize in GM Transmission. You may want to try to find them in your area and see if they can help you diagnose it. IIRC, they can plug a computer and test the trans while you are driving it to diagnose it.
 

TurboFiat124

Thread starter
Joined
Apr 29, 2012
Messages
205
Location
East Tennessee
Hey thanks for the comments guys. I called the shop that did a tune-up on this vehicle about 10,000 miles ago when my father owned it. Ordinarily I would have done it but at the time it seemed as if the fuel injection system was dumping excess fuel into the engine (like a bad fuel pressure regulator). It turned out the distributor cap and rotor button were worn out! I figured by 1998 about all GM vehicles had coil packs! These guys used to work for the local Buick/GMC dealership before it was sold off to the Chevrolet/Cadillac dealership and started their own business. Anyway he told me he would advise against doing a transmission flush. Just drop the pan and replace the filter and add new fluid to whatever is lost. Of course half of the old fluid is going to be left in the torque converter. So I guess half is better than nothing. He couldn't say whether it sounds like a transmission issue without driving it. He tended to think it was some sensor on the engine acting funny. I went to town today to pick up a few things and the van never acted up. I'm going to change the transmission filter myself for now just for peace of mind and see what happens.
 

TurboFiat124

Thread starter
Joined
Apr 29, 2012
Messages
205
Location
East Tennessee
Originally Posted By: Miller88
Also - have you checked the U Joints in the driveshaft? How about the slip yoke?
I asked that same guy if he thought the U-joints may be worn but he said it would clunk when going from drive to reverse or vice-versa. In my case, the van just jerked below 5 mph.
 

TurboFiat124

Thread starter
Joined
Apr 29, 2012
Messages
205
Location
East Tennessee
Originally Posted By: The_Eric
A shudder or vibration pulling away from a stop that smooths out with speed? I'd say it sounds like a misfire. Check plugs, wires, cap and rotor. Pay particular action to the coil wire. I'd be willing to bet its burnt through.
It felt more of a mechanical "jerk" to me. My father had this van tuned up maybe 10,000 miles ago so I wouldn't think it would be a misfire. The van runs incredible smooth otherwise.
 
Last edited:

TurboFiat124

Thread starter
Joined
Apr 29, 2012
Messages
205
Location
East Tennessee
It may sound crazy to keep this old van going but a new one like this lists for $60,000. I gave my father $6000 for it. It's in relatively good shape for it's age and mileage. It has a few battle scars but has the original paint. It did have a body kit but the ABS plastic it was made of got damaged over the years from road debris, mishaps, etc. I covered up the screw holes with body filler and touched it up with touchup paint and covered up the other holes with side moulding. So I wouldn't have to have the entire vehicle repainted. The conversion company removed the air dam and I could not find one so I made my own out of landscape edging! It's great on long trips, my daughter can get into it easy, has a TV and DVD player to keep her occupied, seats seven people plus luggage and I can pull my collector cars to car shows with it. I did have to update the TV and VCR. Gas mileage is horrible at 9/16 mpg but I guess that is to be expected on a heavy van with a 350 V8 engine. The other day I had to replace one of the power steering hoses and work on one of the brake calipers but so far I've been able to do all the work myself. It does creak and go on like the suspension bushings are worn but otherwise runs and drives great. I guess if I had to replace it, it would be with a new Ford Transit. More photos of "The van" : http://s222.photobucket.com/user/turbofiat/library/Chevy%20van?sort=6&page=1
 
Last edited:
Joined
Sep 23, 2007
Messages
8,598
Location
Florida
If your van is down on gas mileage and the transmission acts weird, it may be because of: 1. the fuel injection spider that was used from 1996 to 2000 on GM vans 2. Worn spark plugs, plug wires, distributor cap, and distributor rotor. I have heard some BITOGers recommend just replacing the entire distributor. 3. Mass air sensor becoming less accurate. You can easily remove the mass air sensor, blast it with CRC MAF cleaner, and reinstall it. 4. O2 sensors no longer reacting quickly enough. Usually you get more than 146K miles from a transmission in one of those vans, but not everybody will get the same mileage.
 
Joined
Oct 9, 2005
Messages
339
Location
TN
My 1994 Silverado has a 4L60E and I had to have it rebuilt at approx 190K miles and the torgue converter replaced at about 260K miles. Having said that twice it has had issues similar to what you describe. I do not remember if I had a clunk when it occured. The first time changing the plug wires resolved the problem. The second time I decided while I was in there I would change the cap, rotor, plugs, and wires and it also resolved the issue. These parts were cheap and very easy to replace on my truck. Not saying this is your problem but just my experience.
 

TurboFiat124

Thread starter
Joined
Apr 29, 2012
Messages
205
Location
East Tennessee
I think the guy did a full tuneup on the vehicle due to the worn distributor cap. Dad usually sticks the receipts in the center console and when I bought it I saved them. So I need to check and see if the guy replaced the plug wires. Otherwise the van runs smooth. It was just the other day. As far as poor gas mileage, I think 9 mpg going back and fourth to work (several red lights) and 16 mpg on the interstate is normal for this van. Based on what other van owners have told me.
 
Status
Not open for further replies.
Top