Hi all,
I'm a newbie here as I just bought my first Hummer. Mine is an '03 that was a previous theft. My question is; the tranny is grenaded and before I replace/ rebuild it, are there any known issues with these that I should avoid? As I understand the transmission in this year is '03 only and only found in the H2 and 1/2 ton 6.0L trucks.
I got a fair deal on it, but don't want to break the bank on the tranny in case there are other issues following. It starts and runs well but wont come out of park. I dropped the pan and found a pile of metal chunks. My guess is that one of the piecesfound it's wayinto a hole and won't let the linkage move.
Thanks in advance,
David

 

my suggestion is to get ahold of www.schramsauto.com and see if they have one.... and the trans in your truck is the same as the Escalade, which I believe is the 4L65E, the trans mated to the 6.0L in the pick-ups is the 4L80E which is different.... I don't know if the 4L80E is the same physical housing as the 65, but if it is, I would go with te 80 as its a stronger trans.... Schrams sells lots of really good used GM parts, generally for a good price...

 

I forgot about the Escalade, I thought I was going to be limited to finding anSS or H2tranny. I have used Schram's in the past, I'll definately give them a call. I was going to check Triplett alsoas they deliver to us. My biggest concern with buying used was getting 45 days into a 30 day warranty and back in the same boat that I am in now.

 

My 03 radiator tranny cooler broke and took out my trans. I would suggest an external tranny cooler or an updated radiator.

 

How would I know if I already have an updated radiator? MyH2 has 68K on it already. Do they usually break at or by a certain milage?

 

the 4L85 is not the same size as the 4L65 but you can swap them. The 4L85 is much stronger. It shifts better end there is less gap between first and second. go to transmissionscenter. com If you swap stay with the 1400 stall speed for the torque converter. A higher stall speed does not work well with the hummer and overheats the tranny. the car is too heavy for a higher stall speed

If you have a standard engine and 34" wheels you can also go with a reinforced 4L65. look at the same website

 

I already have a used tranny, it may already be in the truck. I had expected to get it rebuilt but the guy doing it said it was nonrebuildable. The front gearset had broken and took the case with it. I didn't want to leave it setting around his shop too long ( he didn't want to let it outside) so I found a used one with 60k from LKQ. I paid another $200 and got a 12/12 warranty. I had asked the guy doing it if I could get a 4L85E in there and he said they are too different?
I am still going to check out that site though.

 

I did the swap on mine
so it is doable. It is quite expensive but it works perfect

 

I also have an 03 H2 and it slips very bad from 2nd to 3rd under normal driving conditions ( will rev from about 3,000- up to 5,000) before shifting) it also seems to surge when it goes in to overdrive at around 55mph-60 mph. Does anyone have anny advise on how to fix without replacing the tranny?

 

that sounds pretty bad.
3rd gear on a 4l65 is the weakest
you can have your transmission revised with a more powerfull band and uprated valves. You can put in corvette valves. These ones compress the band harder and therefore can handle more power.
How is your transmission temp?
Does is rise very fast when it slips?