Transmission Slips after Rain Storm

I recently purchased a 2001 Chevy G3500 Cargo Van (V8) with approximately 95,000 miles on it. Mechanic checked it out, everything looks good, recommended doing a tune up in the near future because original plugs still in-use. Here is my only (fingers crossed) major problem with the van thus far:

It seems that every time after a heavy rain storm, the van has serious problems when it is first started up and driven for about a half an hour or so. Today, the van would barely start at all. Basically, at low speeds (1st/2nd gear), it seems like the transmission is slipping in some way. It feels as though the car momentarily stalls &/or sputters when light pressure is applied to the accelerator. I guess another way to describe it is that it feels a little bit “jerky” for a split second or two either right after the accelerator is pushed (after the van is stopped) or right before it goes from first to second gear.

Any ideas? I am pretty clueless when it comes to anything under the hood and I don’t want to get ripped off by a mechanic.

Also - on another topic I have noticed the van pulling to the left when the brakes are applied, even after having new tires and an alignment installed. I am a carpenter and have a lot of tools on board - could this be just from an uneven weight distribution in the van? It seems as though this happens in a more pronounced manner after reversing the vehicle out of a parking spot with the wheel turned to it’s maximum point (one way or another), but I could be imagining things.

Thanks all for your help!

I don’t think your transmission is slipping. When it rains there is more hummidity in the air. This moisture seems to be affecting the performance of your motor. It is missing and hesitating when it is raining. This means you need that tune up soon. After the tune up has the van running properly then you should take off just fine.

The car pulling when the brakes are applied means you need some brake work. This is a safety issue and should be checked out ASAP.

I agree with the engine tune up. A one ton van at 95,000 miles has spark plugs with 130,000 miles on them when compred to a half ton truck. The engine has to spin around a lot more with the gearing of that van. The brake problem is a little more difficult to guess at but maybe the idler arm is worn out and the alignment place didn’t notice or the right front brake isn’t working. Make sure they put the right pressure air in the tires and not just 35 PSI. I figure you need at least 55 PSI.

All too often, drivability problems are mistaken for transmission problems. This can be a very expensive error. Have a drivability guy look at it before you go doing anything to the transmission.


I agree with the previous posts.
It is time for that “tune-up” that was recommended recently, and I strongly suggest that this include replacement of the spark plug wires.

For reasons that I can’t figure out, many people seem to automatically suspect the transmission when their vehicle hesitates while accelerating. As transman pointed out, this confusion can lead to an unnecessarily huge repair bill, especially if you were to take the truck to AAMCO, Lee Myles, Cottman, or any other transmission chain. Places like that would be only too happy to sell you a $3,000 transmission overhaul when all that was necessary was new spark plugs and plug wires.

As to the brakes, the problem could be worn front-end components, and since this is a safety issue, you should really get this checked a.s.a.p. As was suggested, it could also be a case of incorrect/uneven tire pressure or an actual brake problem. Only by having it checked by a competent mechanic will you know the actual cause.

Thanks everyone for the advice. I was a little bit weary of the braking issue because when I purchased the van I had new tires put on and a state inspection performed by a local mechanic I have never been to before. In Pennsylvania, they require a brake inspection every year, and since I passed the inspection back in January I assumed all was OK…but I will make sure my tire pressure is good and get a second opinion on the brakes if the problem continues. Thanks again!