I have (from what I can tell) the standard duty TC, with a 5spd. I'm having problems with it engaging into 4wd (or I should say I'm pretty sure it is the TCase). In 4HI, the 4wd / TC will engage after the tires spin a bit in the mud, however in 4LO, the TC will never engage on its own. (That is to say, the low gearing is there but the front wheels don't lock up in 4LO) If I switch it into 4HI until 4wd engages and then move down to 4LO, occasionally the TC will stay in 4LO and with 4wd engaged, but usually it is only 2wd with low gearing when in 4LO. This is accompanied by the 4LO lever sometimes liking to pop out of 4LO and as a result I have to hold it back into position to prevent it from slipping out of gear (truck then goes nowhere, ie 0wd, and the TC makes a nasty grinding / rattling noise as the TC shifter knob and lever shake like crazy, almost as if the gears were grinding) I'm hoping to not pull the TC untill I have some sort of hunch of what I might be up with it. Any educated ideas guys? Best guesses?
I've got this bad feeling that I'm going to be replacing the whole TC soon. FWIW, it hasn't really gotten any worse over the past year, and now that I got the vaccuum CAD freed up, at least I get 4wd HI.
Thanks guys for your help
Long live the 2'nd GENs!

Thanks guys for your help
Long live the 2'nd GENs!