After the first transmission replacement, 6 months later the exact same thing happened again. The trans cooler busted in radiator but this time as soon as the rpm's jumped I shut it down. This saved me from replacing the transmission again. I did replace the radiator again but bypassed the trans cooler in radiator and installed 2 coolers in front of radiator, added a snorkle just because, and I ended up replacing the valve body because swapping solenoids didn't work. Bam, it ran better than before with the engine maxing temp out at 212 and the tranny averaging 95 degrees F, sitting it might reach 120. This lasted for 8 months and onto my next issue in the next post.

Had my hummer lose power while driving home, had only one gear and could only drive about 50-60 km/hr.

When the mechanic looked into it he had originally thought my transmission was shot, but after flushing the thick hot chocolate looking oil that was mixed with the coolant because of a small leak in the tranny cooling system, it was running and shifting fine.

If you have the same issue tell them to pressure test the rad and check the cooling system for the tranny, I had coolant in the tranny and tranny oil in the coolant.

Total cost for this repair was $1180 for parts, oil, coolants and labour

I bought my h3 from a Nissan dealer in 2014. Had no problems with it at all until 2015. First problem, and oh what a problem it was, was the transmission going. For no reason at all it seemed, it started doing the transmission shake. Like when you would hit the gas it would start struggling and shaking and couldn't go. That happened for a few days then quit. Everything seemed to go back to fairly normal. Then a couple months later it seems to be having trouble catching a gear. 2nd to be exact. It started out where it would only happen every now and again then within just a few days, before I could even set it up to go back to nissan and be fixed(had an ex. warranty at this time), I was coming back from a friends and I couldn't get it over 20mph and that was a struggle. I was scared to death, luckily it was kind of late and not many people on the road. I was about 12 miles away from home. I had to put on the emergency flashers and ride 20mph the whole way home and it didn't even wanna go that fast!! Had to have it towed to Nissan and come to find out there NO TRANSMISSION FLUID IN IT?! wtf!? There was no puddle, no leakage, no signs of this AT ALL. The transmission had blew. We let them fix it. the rebuilt it and it would have cost close to $1500. It takes months to get this done. So when it is finally done I had a family member pick it up while I was at work. Let's just say, that was a waste of 2 months. I will post another complaint on the transmission right after this one because I guess this next part would count as another problem because it had to go into the shop again.

Had my Hummer H3 worked on at Ron Carter where I bought the 2007 H3 in 2007 new. They do all of the services to the car, they replaced the front short drive shaft about two months ago then I started having problems with the transmission. Took it back and now they say I did not have any transmission fluid and they needed to change it out at a cost of about $3500. I said I never saw and fluids leaking out and the body was dry under neath . He said they last changed out the fluid at 90,000 miles and I have 157,000 on it now. He said I am supposed to change it every 12,000 miles. Where did all this fluid go to and when they changed out the drive shaft two months ago shouldn't they have checked the fluids?

The forward sprag in the transmission of my 2007 Hummer H3 broke. Paid $2200 to get fixed. Researched this problem and saw where GM released a "bulletin" in 2010 that this part could break on 2006-2008 of almost all of their models of trucks. Located a forum where a number of individuals with GM trucks had had the same problem...having to spend a couple of thousand dollars to repair this problem. This should have been a "recall" and never just a bulletin. Also, this part broke as I was pulling off from a stop sign. After a few inches moving forward, the truck literally stopped in its track...as though I'd placed the truck in neutral...luckily no others vehicles were behind me that could have run in the back of my truck if not paying attention. However, if I had been on the major freeway the outcome would have probably been much worse...think of the truck stopping in its tracks at 70 miles an hour...with cars rolling the same speed behind and on the side of you...scary!