I took my van to a third transmission shop which was highly recommended. They kept my van a few days then called me back with a couple questions. One of them being if I just changed my fan clutch in which I replied back YES. they had me come down to the shop because they wanted to show me something. So I did. The shop rep and I took it for a cruise and he hooked up a computer to my van as we drove. He showed exactly what was going with the tranny and told me that there was nothing wrong with it. Rpms where spot on with the shifting. The van was still making high revving noise and so I pointed that out to him. He told me that he gets this problem about 5 times a summer. It's the new FAN CLUTCH. He told me fan clutches are notorious for being bad from the auto parts store and ordered me to buy a factory one. I did so and problem went away.

 

Thanks for posting back, this is interesting.

so was the fan clutch failing to engage or failing to disengage?

I gather your van was actually shifting into OD but was the sound the fan failing to slip and causing the sound. Without a tach it would be hard to know the rpms.

not doubting the issue just trying to understand it. Thanks.

 

I doubted the issue to the point I actually lightly debated it with the tranny guy. I believe it failed to engage at higher rpms. But, the noise was so loud and similar to the sound of a non shifting transmission that I mislead. The major malfunction is due the fact I've never owned a vehicle that had a fan clutch but, now I'm educated lol.