Drove all last week with no noticed issues. Parked it for about 4 days. Had to do some running around with the truck today when I noticed the issue. Started off with just a slight hesistation when responding to the accelerator, especially when coasting or at a dead stop. Checked air filter - looked dirty, so figured now was as good a time as any to change it. Ended up having to go to a second parts shops to find the filter - still surprised Canadian Tire didn't have the one I needed in stock. By the time I pulled out of the second parking lot and got about 4 blocks up the road, well, that hesitation issue that I had noticed about 20 km earlier was now a major issue. The only response I got when the transmission was in any of the forward drive gears was to walk on the gas pedal, and then it was like the truck was skipping/slipping.

Managed to get pulled off into a parking lot. Tried reverse - works fine. Drive or 1st or 2nd - doesn't even engage - just the engine rev until high RPM when it lurches just a bit. No grinding sounds or anything at all from the tranny. Even tried 4x4 after locking the hubs - no effect there either.

Checked the tranny fluid - seemed low, but couldn't tell for sure as the dipstick had fluid on it but not a real good visible indication. Hiked back to Canadian Tire and got a funnel and a bottle of fluid. Seemed to make a difference, but still, no real visible line. Thinking that it might have just been getting fluid that was in the fill pipe. Took a look up in under - I don't even pretend to be all that knowledgable outside of an oil change or belts - and saw that there was some dampness around what I figured was the transmission.

Had checked the service manual earlier and one of the possibilities was that it was low fluid. Was also talking to my brother-in-law (a backyard mechanican but in another province) and he was thinking that it might be the same issue.

Long story short - I've got two 12hr day shifts to punch, followed by 3 nights. Figure the earliest that I'll be able to look at it again will be Thursday night/Friday morning (still sitting in that parking lot - got the ok from the manager of the business there). Brother-in-law said to try checking the cold level as he had heard of a few issues where the same symptoms occurred on excessively low ATF levels. If that's the case, at least I can get plenty of fluid into the truck to get it somewhere.

Any other ideas as to what I might be looking at? Like I said, no grinding, and reverse works fine. Just not engaging the forward gears.

Thanks in advance.