Transmission?
 

Hello I have a 2005 H2 Hummer and I just had a complete tune up to include the transmission, well today I drove it and when I come to a stop the engine seems to want to run ruff idle but when I give it some gas it runs fine, but it only does this when I come to a stop or when I'm idling at a stop light or in traffic, soon after that while driving home I noticed that the transmission gage was above 200 I was told that is normal well while driving the hummer seemed like it was not changing gears when you speed up it felt like it was staying in one gear but at the same time struggling to get fuel then when you do come to a stop the engine would die but no check engine light would come on, just the battery light. I can still shift the transmission into other gears and it will still drive and even in reverse so that tells me that the gears are good so I'm thinking that the transmission is slipping but I'm not sure because it does not do this all the time I could go for weeks then I have this issue out of the blue. Also there is no trouble codes that show I have any issues so it's at the dealership because they just completed service so I took it back to them I'm hoping it's not the transmission that went out, but the dealership Mech believes is has something to do with a sensor. By what I just described does anyone have any ideals what could be wrong with her?
Thank you

Transmission update
 

Well sad news the GM dealership said the transmission is dead for some reason the transmission was burning the transmission oil and the weird thing is I just had a full transmission service to check for these kind of things, I even had the transmission oil tested for this very same thing. So I now have to pay out $3,500 for a new GM Hummer H2 transmission including parts and labor and GM says I get a 100,000 mile warranty and a 3 year warranty on top of that including parts and labor, GM only had a few New Hummer Transmissions still on the shelf. other wise I could have gotten the rebuilt from GM for $1,000 less but no warranty comes with that. The old transmission only had 123,000 miles on her this even included regular service all the way up to 100,000 miles. I guess the extra 23,000 miles added did her in, LOL

Make sure you check that your radiator isn't leaking internally if you haven't bypassed the stock trans cooler in it. Your symptoms sound reminiscent of when my H3 tranny died from coolant mixing in the trans fluid. You don't want to have the same leak destroy your new transmission. Especially since you took it to a dealer (I don't trust them at all).

I agree with passing the radiator.
3500 for the oem isnt a bad deal but what would warranty it won't happen again in 101k miles right when run out warranty

The Gm trashmisions are know by failing around the 120k
Mine did .

I went with street smart transmission. The cost shipped was$1400
install was another 550 . Total 1950
transmission was upgraded but not a Heavy duty
For $3500 I would get a Heavy duty custom made . No more worries

Thank you for the reply back They already ordered the transmission but I will take your advice about to make sure they don't bypass the transmission cooler for the radiator coolant. I see I have 3 coolers two on the front of the radiator and one behind it. I just had all new radiator lines installed they were leaking at the mounts they needed to be replaced. I know you don't trust dealerships for work but I have always had back luck with back yard mechanics or in this case Auto shops, that's just me. I also found out today that this Hummer still had the factory Transmission and I noticed that the last owner installed a breaking system for towing. I love this Hummer but oh my god you can't replace burned out lights in the dash anymore you end up replacing the whole component. My next project is replacing the dash cluster half the lights are out and my RPM gage is stuck on 4 so the stepper motor is going out don't even ask what that cost to replace, LOL

Again thank you for the advice

Not sure if that was a typo or you misunderstood. If you stick with the oem trans cooler, and your radiator leaks internally, the fluids will mix and destroy your transmission. You need to figure out if that happened before you replace your transmission so it doesn't happen again. What most people do is bypass the trans cooler in the radiator and install a separate one bypassing the radiator completely. Also, you can have your cluster refurbished instead of buying a new one. Half my cluster lights were out and my shift indicator was super dim. I had it repaired by an electronics seller on ebay who restores GM clusters for around $100. They guarantee it for life. A lot better than replacing it in my opinion.

Transmission Dead
 

I got some bad news today. I have a 2003 h2 and my granny is a mess
my radiator mixed with coolant and to repair it and everything else that went bad because of it is going to cost 6000 dollars for vehicle I am financing and have only had it 3 months. I am upset but I luv that car and it will come with a 2 year parts and labor. The bad thing is I have a warranty when purchased but the tranny died before the warranty kicked in.