And Doc I did check coolant and its fine and level it should be..

 

Yes, in limited specific context.

 

When Trans is in "D"rive does it start out in first? If yes, look at the linkage.

You do not have to shift gears ever before changing the Trans Fluid & Filter, that's internet Bull Chit. There are how to vids to search for your H3 Hummer Trans Fluid & Filter change.

Read this thread for more re: vibration: Acts like it wants to stall/rough idle -No CEL -What To Do:

 

Doc I meant when trying to shift through the dash lights (P, R, N, D, 3, 2, 1) I get through all and the dash lights up showing I'm shifting but when I am at "2" the shifter has no more room physically to go back into "1". Its not stuck it just has no clearance to go farther its almost touching the bezel ring around the shifter

 

And Doc I've done everything you listed in that thread except #7 but it isn't stumbling or having a hard time idling just making rattling sound and vibrating like crazy!
Thanks for the help really appreciate you!

 

Time to take it to a mechanic & get a free estimate.

 

Yeah, I get that. What I asked is, when in drive does it start in 1st gear? If yes, then it is a linkage issues, not trans internal. Whoever did the T Case work before you bought it left you with a linkage out of adjustment.

 

Yes once I put it in drive from park it is in 1st and shifts smooth through all the shifts as far as rpms go.. its an 06 and the carfax says it had 2 transfer cases replaced a month apart in 2007..the previous owner seems to have had maintenance done and had it serviced (is in really good shape for an 06) but shows no other work to the transfer case since the 2 replacements..

 

Possible very likely solution/answer/problem identification = Transmission shift linkage out of adjustment.

The above does not explain your leak and only relates to your complaint that manual shifting to 1st gear does not work.

 

i mentioned that on the 6th post. yet we are still here.......