Transmission OUT! Advice?

[Jeremy]

Okay, so heres the rundown.

My '07 Hummer is in the shop and my transmission is being gutted and needing to be rebuilt. Since I don't know hardly anything about transmissions I can't provide exactly everything that mechanic told me is wrong with it but he basically said that everything was burnt up inside and the fluid was black. I've always heard that transmission fluid should be changed at 100,000 miles and my truck is at 99,000 when it **** on me.

The transmission struggled to switch out of second gear for about a week. I was hoping it was that I was low on fluid but by the next day it wouldn't switch out second at all unless you put it in third manually which still didn't do much for me considering I live in the foothills of the smoky mountains and my truck wouldn't make it up hills faster than 20 MPH.

I travel A LOT! I drive at least 500 miles a week. I hate putting the miles and wear and tear on my truck but I have no other choice right now.

Has anyone had these problems with their transmission? Is the H3 known for tranny problems?

The mechanic told me that it wasn't preventable and that these stlye of transmissions are known for problems.

 

[Best4x4]

I have 124K on my Alpha, and I know the fluid and filter have been changed and it shifts like a new truck! I changed the filter and fluid on my 07 H3 when I bought it and it also shifts like a new truck with 86K on it. The transmission has been around for years, and while it isn't the strongest transmission out there it is a proven unit. You can beef it up some, and add a cooler to help with towing or hill climb temps.

 

[amrg]

My dealer schedule has my trans oil changed every 30K!

 

[SuperBuickGuy]

your transmission was slipping... do you tow much? I burned up a 700r4 towing a trailer in overdrive (that wasn't the worst I did to it, simply an example of how poorly I treated it)... I don't get the 100k fluid replacement for the transmission or the coolant. IMO, you should do that every 50k with normal useage, and sooner if, during oil changes, you notice the fluid getting a bit funky.

 

[Jeremy]

your transmission was slipping... do you tow much? I burned up a 700r4 towing a trailer in overdrive (that wasn't the worst I did to it, simply an example of how poorly I treated it)... I don't get the 100k fluid replacement for the transmission or the coolant. IMO, you should do that every 50k with normal useage, and sooner if, during oil changes, you notice the fluid getting a bit funky.

No, I don't tow anything. I do drive through the smoky mountains every weekend between TN and NC due to traveling for my job and my RPM always jumps up a good amount when going up really steep slopes with my engine being a 3.7L I5. I wonder if that has anything to do with it. And I will be changing my fluid every 30K after this.

 

[MaxPF]

If you had never changed fluid then it was certainly sheared down and loaded with contamination. 25-30k are proper intervals for a trans fluid change. GM might say 100K or whatever with Dex VI, but they don't have to pay for a new trans in when it dies out of warranty.

4L60E's do have problems, but with care and normal driving they often go 100k-150k miles. Yours failing at 100k is actually pretty good considering you've never changed the fluid

 

[Best4x4]

I'm pretty sure my original transmission is going to pass 150k with ease. Fluid is clean, shifts smooth, and it shows no signs of giving up in 25k!! It's all about how the rig was treated, and maintained!

 

[CaseyS]

For what it is worth, my original transmission made it to 259k indicated (over 275k corrected) without ever changing the fluid. Was that smart? Probably not.

While it is out there are some simple and inexpensive things you can do to it. Change the servo to a corvette servo. Will liven up the 1-2 shift. These are about $20. Upgrade the sun shell to a beast or hardened sun shell. That should be standard with a rebuild but you should ask. Also look into a 7 clutch 3-4 stack. Stock is 6. The total of those upgrades are on the order of $100. A good shop should be able to quote you in the $1500 range for a rebuild plus labor.

After you are done, look into an external cooler. Should help your longevity in the mountains over there.

 

[zackcrum]

made it to 259k indicated (over 275k corrected)

Geez I can't believe a h3 made it to that. I'm at 169k and I thought I was doing phenomenal

 

[SuperBuickGuy]

No, I don't tow anything. I do drive through the smoky mountains every weekend between TN and NC due to traveling for my job and my RPM always jumps up a good amount when going up really steep slopes with my engine being a 3.7L I5. I wonder if that has anything to do with it. And I will be changing my fluid every 30K after this.

Nothing you say says tough use, I had 110k on my first h3 (an 07 - the one I used to haul a diesel suburban and car trailer) and my current H3 has 115k (which is leading a tougher life than the first) - while the pre-electronic 700r4 transmissions made it 110k, the new ones can last as long as the motor.... sometimes it's just luck of the draw, I guess. As I said before, change the fluid when it smells funky, for you and your driving style that could be every 30k... but with that said, at $7.00 a quart and you need 12 quarts (with converter), you may not save much money with the accelerated fluid changes vs. trans rebuild costs... especially after you update your current transmission with the rebuild.

 

[Mr_Rich]

I think by leaving the truck in third rather than overdrive will help immensely. The 700R4 in my '89 K1500 survived for over 225K miles with infrequent fluid changes (and a deep sump pan that increased the fluid volume). Around town and every time I hit a steep grade I'm always in third gear. I save OD for easy highway driving and it pays off. When I hit the bottom of a grade I hit the throttle a little harder to automatically shift to third before I manually shift the lever to third. I think that's a reasonably gentle way to keep the trans in third gear rather than having the trans keep hunting between the gears while climbing the grade. Two years ago when I was swapping out the engine and trans I went with a budget trans rebuild which was false economy. The trans failed in with third and fourth gears less than 100-200 miles running. I went with a BTO trans after that which I'm very pleased with. Whoever rebuilds your trans make sure they aren't big talkers and can back their rebuilds with successful results.

 

[SuperBuickGuy]

I did learn from that whole other burned up transmission bit - if you are maintaining a steady speed and you watch the tach moving up and down.... it's time to shift down into a gear it can hold. Problem is, of course, that 3rd and 4th gear use the same clutches - so if you overheat them in overdrive, it may not come back.

 

[stvnkrchnr]

Off topic kinda but have you ever changed out your Tcase fluid? It should be changed out pretty often. I try and do mine every 20,000 ish miles. Just another thing to keep in mind.

 

[Jeremy]

Off topic kinda but have you ever changed out your Tcase fluid? It should be changed out pretty often. I try and do mine every 20,000 ish miles. Just another thing to keep in mind.

No. I never changed that either. I was under the impression that the Tcase fluid and Tranny fluid could go 100,000 miles but sonebody lied to me lol. I will definitely be changing my fluids more frequently now though.