Transmission Issues.. plus voltmeter

I just bought a 94 Explorer with 158K on it. Its an auto with 4WD. Engine runs great, but I have numerous issues with the tranny, most when the car is cold. What happens is this:

Start Expolorer... put it in OD and pull out... have to rev the engine gently to get tranny to engage, which it does. What happens after that is generally I am going along and it goes to shift up and it feels like it is in neutral until revs hit 2.5K or so and then it engages. This continues for about 10 minutes, gradually getting better, until I might go an hour or more without having it happen. Additional symptoms... come to stop and after a full stop (2-4 seconds) you can feel it drop down. From a stop (when cold) you have to gently rev it to enage drive.

Had a mechanic look at it, he tightened a bolt on the tranny, said I had a plug that needs a rubber seal around it (leaking a bit) and reccomended i replace the tranny cable. Before I go barking up that tree I was wondering if anyone had any suggestions?

Oh... the voltmeter sometimes works, sometimes not. The gas gauge doesn't at all and I figure thats the flot full of gas issue.

Thanks for any help.

I have a '94 Explorer Eddie Bauer, 265k miles on it. Had similar issue and found it to be an O-ring on a plug on the side of the transmission. It's a bear to get to so I let a mechanic I know do it for me. Don't remember what I paid him to do it but it was worth it to me. Stopped the loss of fluid and tranny worked fine after that.
Why is he recommending replacing the tranny cable?

I have a '94 Explorer Eddie Bauer, 265k miles on it. Had similar issue and found it to be an O-ring on a plug on the side of the transmission. It's a bear to get to so I let a mechanic I know do it for me. Don't remember what I paid him to do it but it was worth it to me. Stopped the loss of fluid and tranny worked fine after that.
Why is he recommending replacing the tranny cable?

Thanks for the response.

I believe I have the same problem but its gulping 1 quart of tranny fluid every 500 miles or less. Not a big problem though one I have to get fixed. As far as th ecable goes, ge didn't give any real indication except it felt loose. My main concern is the lackluster acceleration but I can live with that, so long as it keeps on keeping on.

My other concern is that the mechanic at the place I bought it noticed the oil level was high, so he drained it. When I took it in for an oil change, it was high then as well. After the oil change (not right after) I saw that it was over full again. About 1/2 a quart or so. For a while I was worried that somehow the tranny fluid was getting into the oil but that does not seem to the case. Now I'm concerned that maybe I got the wrong dipstick or there is something else wrong.