Problem with van

paullud · Apr 19, 2011

It seems like the transmission may be searching for a gear and having problems after coasting.

Moot · Apr 19, 2011

By "coasting" do you mean taking your foot off the throttle?

If your problem is intermittent buy a ScanGauge: ScanGaugeII - Trip Computers + Digital Gauges + Scan Tool

The ScanGauge has a (TPS) throttle position sensor function. This will allow you to diagnose the problem as it occurs. When ever you completely let off the throttle the TPS should show a value of 0. If your throttle is "sticking" this could cause shifting problems.

Buy a ScanGauge anyway. Well worth it!

Godwindaniel · Apr 20, 2011

davekc said:
I don't know if it is common as I haven't seen this problem posted. Keep in mind that I don't drive a van but know a thing or two that may give a point to look at.
If they changed the converter, then I would proceed to the yoke, drive shaft (could have thrown a factory weight), u-joints, and possibly a pinion gear. I don't believe a a van would have a carrier bearing, but if so, another place to look.
Last but not least, a bad or loose engine mount would do it as well.

I think he is right, I didn't met a problem like this earlier.

jrcase · Apr 21, 2011

Well after four days if them looking over my van. They can't seem to duplicate the problem. At this point I am ready to trade it in on a Ford. They are taking turns driving the van trying to get the issue to happen. The last time I left it with them they burned over fifty dollars on gas. I can't wait to see how much they burned this time. Grrr......

guido4475 · Apr 21, 2011

Turtle said:
The torque converter is what I'd have looked at first, even with only 50,000 miles on it. A dirty Mass Airflow Sensor can cause that problem. But the "always after coasting down a hill and start coming up the next hill" deal sounds like a classic case of the ignition coil going bad. A $40 part and 20 or 30 minutes to change it out should do it. It could be wires or plugs, but since it drives fine otherwise it's probably the coil, or the connecting wire to the coil. Shuddering after coasting, especially while towing something (like a boat) but otherwise is fine, is generally an ignition problem (particularly with so few miles on the vehicle), usually the coil or the connecting wire, either or both of which can become corroded easily and quickly.

You know, I had a Ford 1985 station wagon with a AOD trans and a throttle body 5.0 do the same thing.From the way it was acting, everyone said the trans was slipping.So I had it rebuilt, and guess what.It still did it.Come to find out, the plug wires were bad, after a year old.Who would of thought? So I am with Turtle on this one.Plug wires/coil packs.

jrcase · Apr 21, 2011

guido4475 said:
You know, I had a Ford 1985 station wagon with a AOD trans and a throttle body 5.0 do the same thing.From the way it was acting, everyone said the trans was slipping.So I had it rebuilt, and guess what.It still did it.Come to find out, the plug wires were bad, after a year old.Who would of thought? So I am with Turtle on this one.Plug wires/coil packs.

If they can't tell me something for certain, I will replace them. They did tell me that there were not any codes , so no misfires.

guido4475 · Apr 21, 2011

Yea, mine was the same way.Ran smooth, idling.Just make sure to get a good, high quality set of wires,none of that Autozone crap.Nothing but junk there, for the most part,even though the warranty cant be beat..

fastman_1 · Apr 22, 2011

I had a 03 with a 5.3 that had the same problem,dealer rebuilt the Transmission,didn't fix the problem,then replace all the U-joints still no fix,replaced the drive shaft,nope still not it,then a redneck friend said coil packs,I thought he was crazy,but problem fixed.

jrcase · Apr 28, 2011

They could not duplicate the problem on the van. Funny. When I drove it home from the dealership it messed up on me.

I am trying to focus on the ignition possibility. The coil will be an expensive troubleshoot as it has eight of them. Maybe I will try plugs and wires first to see of that works.

Could it be water in the gas? I dumped a couple of gas treatment bottles in it today to see if that helps.

Thanks for all the ideas.

scottm4211 · Apr 28, 2011

If you haven't already I'd make sure the dealership has a file open showing your problem/concern. It might help if this continues past your warranty period.

Turtle · Apr 28, 2011

jrcase said:
They could not duplicate the problem on the van. Funny. When I drove it home from the dealership it messed up on me.

I am trying to focus on the ignition possibility. The coil will be an expensive troubleshoot as it has eight of them. Maybe I will try plugs and wires first to see of that works.

Could it be water in the gas? I dumped a couple of gas treatment bottles in it today to see if that helps.

Thanks for all the ideas.

I suppose it could be water in the gas, but it's highly unlikely, as the key to the problem lies in the symptoms, namely, the first paragraph of your original post. Water in the gas wouldn't manifest itself under such strict and narrow driving conditions. Once you narrow it down to what manifests itself under those specific conditions, you can then fix the problem.

jrcase · May 12, 2011

It is back in the shop again. I took the service foreman on a test drive with a scanner connected to the ECM port (I think that is what it is called). He felt the shudder 8 times on our 50 plus mile ride. The scanner didn't pick up anything. He said it was not happening long enough. It shudders in short bursts.

He called Chevrolet and told them that after replacing the torque convertor it is still happening. They told him to replace the TCM (Transmission Control Module).

We shall see what that does. I am rapidly getting tired of this problem not being corrected,,,,,,

jrcase · May 13, 2011

Well, I picked up the van today and so far so good. No more shudder on the drive home. I want to give it a few days to be sure but I think replacing the TCM did the trick. The work order also said they replaced a solenoid assembly. I do notice a difference in driving. It does not coast as well but if the shudder is gone, all is good fingers crossed.

purgoose10 · May 13, 2011

Yes they can be aggravating.

scottm4211 · May 13, 2011

Good to hear. I hope the 6 sp is as stout as the trans it replaced.

jrcase · May 13, 2011

scottm4211 said:
Good to hear. I hope the 6 sp is as stout as the trans it replaced.

The service manager said it was rock solid. he said mine was the first he has seen with any issues at all. The gas mileage is much better compared to the Ford 4 speed.

jrcase · May 14, 2011

I guess I spoke too soon. The stupid thing is still doing it. Not as often but it is still there. No more GM products for me. Back to the dealer next week.

Deville · May 14, 2011

I had an Oldmosbile Auroa with the Northstore motor that did the same thing yoou are describing. Oldsmobile replaced the fuel fliters, the plugs & wires, various sensors, most was under warrenty. Nothing sloved the issue, it would get better but never go away.
The prolbem did reslove evantually when the motor blew & once the engine was replaced it never did it again.

Dakota · May 14, 2011

I had a Chevy Express Diesel van and after they replaced the u joints 4 times due to vibration, I gave up and and the driveshaft balanced and that fix the problem, no more broken u joints

jrcase · May 19, 2011

The dealer placed a VDR (vehicle data recorder) on the van and I presses a red button each time the van messes up. I gave it back to them and heard back today.... They are going to do a 100% swap out of the transmission. I guess the results showed something nasty. Anyway, GM is sending the new transmission and it will be here in three days.

I guess the new six speeds are not bullet proof after all.