Build Hummer H3 Build

Ok! Update time. Drove the hummer for the first time in like 6 weeks (since Moab) that was a grind. The battery situation really left me in a pist off mood then add in all the maintenance crap that didn’t really make anything better it was just not fun.

Anyways, I did my first test run. About 100 miles total, drive 40ish miles of highway there, 20 of dirt roads, rock crawling and small farm roads and 40 miles back on the highway.






It was also super cool to meet this guy.



He’s not on irate but he built this thing 14 years ago on pirate. BEAUTIFUL build. He actually said he has followed my build for years because he has a 5.3 Colorado.

Anyways, fun day, hummer did well. Steering is happy now and has a cooler. It continues to impress me in high speed chop. It can just move through dirt roads and nuisance chop so much faster and more comfy now. It was also fun to have a passenger who usually drives his YJ buggy. He said it’s amazing sitting inside of the h3 and how it goes where it does.

I still consider myself in “testing phases” with the 3 link and 6l80. I have less than 1000 miles on it and only 4 runs on the 6l80, and 2 on the 3 link. I can report that the rear shock mounts hang up way less than I imagined. I think they ramp nicely off the lower control arm so they aren’t a huge hangup in the few runs I have done.

I knew the lower control arm mounts would hit more but they are hitting more than I like. To be honest I am not a fan of the brackets I bought. I feel they aren’t slippery and they are rock grabbers. The leafs were tucked up on a higher part of the frame and farther back.


I will get a better pic when I’m home but you can see how big the bracket is. There’s a decent sized lip on the front, then it protects the entire heim with room to spare. I actually would like a smaller lip and let the bottom of the heim sit below the bracket. I think the transition will be easier.

I won’t be going out to change it immediately but I figure long term change will happen.

I also think I FINALLY have my evap issue figured out. This time I routed the evap line around the entire fuel tank so fuel can’t get to it when it’s full. It didn’t sputter or cause issues this time.

6l80 definitely needs some tuning for the highway. It’s quick to downshift, quick to unlock the TC and I looked at the settings on hp tuners. It still has the factory parameters where the TC never really FULLY locks. It’s so dumb GM asks for like 40 rpm slip when it’s “locked” no wonder why the TC’s have a bad rap in the 6l80. You’re literally burning it up.

I still get a random P2537 which I’ll look into more. It puts the 6l80 in a limp mode basically. I have a scan gauge that allows me to clear the code within seconds and it’s fine. It’s like the ignition sends voltage to the trans a second late and throws the code. It happens maybe 1-2 times a trip and it’s only on startup and off-road. Never on road.

I feel like I can finally breathe though! Last year I did the 6l80 swap, immediately ran the rubicon, then tore it back down, did the 3 link, barely got it driving, picked up the baby from the hospital in it. Then had the evap issues from moving the evap can sister to a lower part of the chassis. So I have been tackling it the biggest issues first and I’m finally checking things off the list. The evap and sway bar were the biggest issues. Smallest issue is speedo reading incorrectly in low range but I know, with time, I will get it all addressed.

Glad to read through a detailed updated and looks like a fun trip.

Great update.

Could you weld some metal from the frame to those brackets? So, it’ll be a smoother transition from the frame to the brackets.

McBastard79 said:

Great update.

Could you weld some metal from the frame to those brackets? So, it’ll be a smoother transition from the frame to the brackets.

Click to expand...

I have thought about that. It’s something I may try first to avoid cutting those brackets off lol

Just got back from the rubicon! I’ll get an update this week. I’m really racking up more and more seat time on the 6l80 and rear 3 link. With the added seat time I’m sure tweaks will be made.

I’m most shocked at how little I hang up on the rear shock mounts. I need a hammers trip. That may be the place I hang up on them the most but so far I haven’t gotten hung up to the point of “this line won’t work because of those mounts”

I’m not sure if anyone saw the rubicon trail Facebook page shenanigans but it was pretty epic. I’ll get it posted up here later

OH ****!!!! Happy birthday dude!!! I wasn’t out there. I just saw some pictures of the party favors your mom asked people to bring you.

Alright guys, this was a fun rubicon trip! It was different in the fact that we have 7 people in 2 rigs. This took a **** load of planning and a lot of cramming 10lbs of crap in a 5 lb bag.

We had myself, my wife and my sister in the H3 and then my brother, his fiancé, my other sister and her boyfriend in his 1 ton JK on 40s.

We had tools, spare parts, fluids, one giant drink cooler, a tiny soft cooler, grill, a fridge freeze, all camp cooking supplies, clothes for us 3 and tents/sleeping pads in/on the H3.

JK had its spare parts, 2 small coolers, dry food, sleeping bags, camp chairs and clothes for their 4 people.

My brothers JK



Then my buddy had his 1 ton ZJ with his brother and dog. his uncle took a can am and had his mom as a passenger and another buddy going solo in his 1 ton first gen pickup.

We had 6 non off-road type people and 4 of those never been on the rubicon.

Well, being filled to the gills we were short on beer. So I texted my mom on my sat phone asking to join the rubicon trail Facebook page and post up we need beer.



The post went viral! The comments were hilarious and posts were made about my mom’s post. My favorite comments were I haven’t had this much fun on a thread since Doug’s axles and I’ve been following this like it’s the election

Anyways, the group of non off-roaders in our group were saying there is NO CHANCE someone will bring beer. I told them just watch, they don’t know **** about the off-road community.

Sure enough the next day, an 18 pack shows up.



Our newbies lost their minds, the first 5-6 groups we saw all said happy birthday, come to my camp for a beer or had beer. They couldn’t believe it.

In the end we even got a happy birthday from the sheriffs on the trail who saw my mom’s post.

The rubicon is the rubicon. It’s the same every time, amazing. This just added a level of fun. We had the perfect balance of camping, swimming, wheeling and hanging out.



Even got some bourbon. Some we paid for, some we didn’t, and some we paid for indirectly.

The first guy who gave us beer ended up breaking his rear R&P. So the hummer towed him from the slabs to Ellis creek where George from unleashed 4x4 met up with him. Timing was perfect because the rear end started locking up and they had to pull the ring gear.

A buddy ripped a shock mount off and destroyed a shock that he needed as a limit strap to not overextend the driveline so the welder came out like almost every trip.



Then after we welded it back on we made a limit strap. Worked perfect.

The hummer worked well but once again I feel the link mounts hit **** too much. I’ll figure out a solution. I was just so used to leafs being tucked up so high.

The only thing that got spooky was going up the slabs. The hummer felt stable going down the slabs and everywhere else on day 1 and 2. I had tents and crap on the roof but it felt fine. Once I put a heavy extremely full garbage bag on top things felt tippy going up the slabs and that spot right before Ellis creek heading out. I probably should have moved the sway bar in 1 hole for more rate.



Me towing the JL out. I hope I paid for the beer by handing out brake fluid to someone in need and towing him out. Trail karma for the win.

I got home Sunday early evening, quickly unpacked, then drove 7 hours to Montana for work the next day so I’ll do a once over on the hummer when I get home but nothing immediate comes to my mind in terms of repair.

06h3 awesome recap and awesome trip!

Went wheeling locally again last weekend, had a good time. We were on the trail by 7 and off by 11ish before it became 100* outside.



This is tech and probably boring to most but I hope it solves someone else’s issues in the future.

Some exciting news is I finally have an accurate speedo in 4 low! I get anal about this stuff. I know it’s stupid but I really do get ocd about it.

So the reason it took so long is that my tuner needed me to send him my tcm which is inside the trans and I didn’t want to do that. I do miss the tcm being external like it was on the 4l60. Anyways, he has a loaner software tool but the cable was not working. He was having issues finding a replacement cable for his tuning software. I guess it’s discontinued and parts are hard to come by but he’s sticking with that software because it’s much less restrictive than HPTuners. He can do some really cool custom **** with his that HPTuners just doesn’t do. Anyways, it’s just a speedo issue in low range and wasn’t affecting the performance so I said find a cable and send it my way when you can, no rush. He’s had no luck with his cable and I finally dug further into it with my HPTuners setup.

Sure enough I could swap the TCM tunes from another vin IF the operating systems are the same operating systems. There are variances in an OS like 2wd vs 4wd.

There are definitely concerns, some say they will brick a TCM, some say they won’t. The 6l80 is a picky SOB and I know it has bricked some TCMs according to the internet. So I was taking a gamble all for a stupid speedo issue in 4low.

But I found a file from a 08 Silverado 4x4 with a 6l90 that has the same OS as my 07 TCM from a Denali with AWD. Since it had AWD it didn’t have a low range provision. I made the tune identical, hoped it wouldn’t brick and it didn’t!

Everything is identical except for 2 things.

1) the speedo reading. Going back to my 4l60 days the speedo got its info off the VSS at the back of the t case. This was great. Whether in 4low, 2hi, double low, etc. it always read the same speed because the output shaft was spinning based on road speed, not gear ratio. The problem I had was if it didn’t know I was in 4lo it would go into limp mode so I had a switch that would ground out and grounding out that pin would tell the pcm I’m in 4 low. So if I didn’t use that switch I would go into limp mode. Dumb but it worked.

Fast forward to the 6l80 it doesn’t care if the computer knows it’s in low or high, it won’t go into limp mode which is awesome but it doesn’t use a t case VSS it uses a speed sensor off the tail of the trans, which does care what range it’s in from a speedo standpoint. So before if I’m in 1.96:1 it would read the speedo 1.96 times faster then I was going. Since I used 1.96 to bomb around on dirt roads at 50 mph, it would say I’m doing 100 mph. In 2.72:1 it was saying I was going 2.72 times faster than I was. So at 30 mph it said 81 mph. What really drove me nuts was 5.33:1 in double low at just 12 mph it said I was doing 60 plus. Even doing 5 mph it was 25+ mph. It drove me bonkers. There was no point in flipping my 4 low switch because it didn’t care.

So now that this vin has 4wd attached to it. It’s a silverado so 2.72:1. I flipped switch and the speedo is dead nuts accurate. What does suck is since it’s still reading at the front of the t case at 20 mph in 1.96:1 the speedo says 15 mph. It’s a little off but not horrible.

5.33 is still about 50% off so at 12 mph it will say I’m doing 23 mph but wayyy closer then before. I do spend a lot of time in 2.72 so I’m happy there.

2nd change is before my PRND321 I had PRND then 3 was tap shift, 2 and 1 were not used.

Now it’s PRND 3 is not used 2 is tap shift and 1 actually holds first which is cool.

I also found out that I can transfer a bin file to HPT file on HPtuners. I think it’s 50 bucks to do so but I’ll gladly pay that vs pulling my damn tcm or paying money to ship crap. So I will talk to my tuner and see if he can write a file on his end and I’ll convert it.

Since he can do custom stuff I can’t on HPT I’d like PRND321 to all be utilized. I’d like 3 to be tap shift, 2 to be 2nd, 1 to be 1st.

I’d also like to see if he can just have me rewire in my old VSS on the back of my 205 I’ll pin that to the pcm and use that. I will look to see if there are early 6l80 applications that had a t case VSS with the same OS because I’d like that, then I can ditch the 4 low switch all together and it will always read right.

Anyways, this is the fun stuff I geek out over.

06h3 said:

2nd change is before my PRND321 I had PRND then 3 was tap shift, 2 and 1 were not used.

Now it’s PRND 3 is not used 2 is tap shift and 1 actually holds first which is cool.

I also found out that I can transfer a bin file to HPT file on HPtuners. I think it’s 50 bucks to do so but I’ll gladly pay that vs pulling my damn tcm or paying money to ship crap. So I will talk to my tuner and see if he can write a file on his end and I’ll convert it.

Since he can do custom stuff I can’t on HPT I’d like PRND321 to all be utilized. I’d like 3 to be tap shift, 2 to be 2nd, 1 to be 1st.

Click to expand...

You ended up using the factory H3 shifter? Do the shift gates for the 4L60 shifter match the 6L80 detents in the trans? …Reason I ask is that I plan to do similar with my cruiser. I would like to have PRND321 rather than PRNDM.

Chkn said:

You ended up using the factory H3 shifter? Do the shift gates for the 4L60 shifter match the 6L80 detents in the trans? …Reason I ask is that I plan to do similar with my cruiser. I would like to have PRND321 rather than PRNDM.

Click to expand...

Yeah my 4l60e shifter works on my 6l80. The 6l80 has enough detents for 7 spots. I think they leave the 6 and 7 empty and only have enough shifter throw for 5 detents and so PRNDM.

My tuner says you can assign the 3 after D to whatever you want but idk if you can do that in HPT

Enjoyed the deep dive into the tune/speedo issue. Even though it will probably never apply to me, someone in the future will be thankful you explained it and documented it on a forum platform vs FaceSpace.

So as you may have seen on Connor’s H3 thread I ran the rubicon again. This was a different trip, in a good way. We ran the trail one way vs the typical park at loon and do loon and back. So I parked the truck in Tahoma, then drove the H3 over to loon. This was about 90 miles between stopping at the grocery store and a Mexican place for some food. It felt awesome to drive it on the road. I had both sway bars hooked up, while it’s no race car, cornering hard (for what it is) and driving “fast” on the winding roads was so fun, especially with the half doors on as you felt the temp changes with elevation. It was a fun experience and reminds me this big dumb thing is still roadworthy, even with big giant loud 43in tires.

The views were phenomenal going around Tahoe.








Got to loon just in time for an awesome sun set.




Going up ice house really made the 6l80 shine. It never was revving at 5k rpm or bogging at 2k rpm. The added gears left it pushing plenty of power at 3000-3500 rpm.

The trans never got close to hot. It worked awesome.

One thing I did notice, is when moving (even slowly) I’d run 188-192 coolant temp. If I was parked it immediately hit 207-210. Granted operating temp on an LS is 210 (every early 2000s-2012ish, GM temp gauge for coolant is 210 in the middle) but it didn’t do this before. The only thing that changed is I went from one trans cooler in front of the ac condenser/rad to 2 trans coolers and a plate and fin power steering cooler. I think they are heat sinking the rad at idle and the fan clutch isn’t moving enough air at a stand still like an electric fan does. I may move the PS cooler. Thoughts?

Anyways, the drive was fun and uneventful.



It was fun to lead and “relive” the rubicon for the first time through 2 others who have never done it. My strategy was to not get stupid. I took optional lines, I hit soup bowl, little sluice etc. but play it safe on some other obstacles to ensure I didn’t break and ruin their trip.

Hummer worked awesome, didn’t turn a wrench on it and was stoked on its overall on road/off road performance.



As with every trip I have a take away. 1) is the B pillar cage mount. It sticks out and makes certain obstacles way harder because I have to bump past that hang up on the slider. I have contemplated making a new one that sits on top of the slider but it would need a bend at the bottom to clear the door making it weaker. This was never a race cage so idk how much it matters.

This is the bump out I’m taking about.



And my proposed revision if I chose to not just let it stay as is. It only happens on certain obstacles.

My other takeaway is don’t be an idiot. I was also cautious with food and bears. For the first time I wasn’t cautious and the bear called me out on it.



My sarcasm didn’t come through, no I didn’t actually feel violated lol

you could turn it into a step, or nice kick out

The main problem is getting past the front part, once I am past the B pillar I am in the clear. Maybe I make it an easier transition

Cut the b pillar completely off and put it inside the cab. Stronger and gives you a place to mount seat belts in the future.

Or, just add that much to the whole slider to make it have no transition.

Sorry, but I hate the above example. People claim they like huge wings on their sliders to be able to pivot off rocks, but fail to realize how they just catch and stop you 5 times more often. On a rig where you're trying to keep the body nice, I get it, but I still say have a consistent line front to back.

Just do this

Also, I totally get what you're saying about rubicon. We did a similar trip last time, parked tow rig and trailer at tahoma, drove the crawler all the way around, which was fun. Then took 2 people who had never been, which was a blast. Took our time, enjoyed the trail.

Only bummer was going back to get the other tow rig at loon. But whatever.

Can't thank you enough chris, definitely a bucket list experience, and I am already planning the next trip.

BS. You baited that poor animal hoping to get some cool bite marks or slashes on your ride. Like youtubzzzz, flakebook, twatter, or tic toc play with your cook cool.

It didn't care about your "likes" and now you're trying to salvage what you got.

YotaAtieToo said:

Cut the b pillar completely off and put it inside the cab. Stronger and gives you a place to mount seat belts in the future.

Or, just add that much to the whole slider to make it have no transition.

Sorry, but I hate the above example. People claim they like huge wings on their sliders to be able to pivot off rocks, but fail to realize how they just catch and stop you 5 times more often. On a rig where you're trying to keep the body nice, I get it, but I still say have a consistent line front to back.

Click to expand...

I'm with you on the kick outs. Have seen them hang up more than help.

YotaAtieToo said:

Cut the b pillar completely off and put it inside the cab. Stronger and gives you a place to mount seat belts in the future.

Or, just add that much to the whole slider to make it have no transition.

Sorry, but I hate the above example. People claim they like huge wings on their sliders to be able to pivot off rocks, but fail to realize how they just catch and stop you 5 times more often. On a rig where you're trying to keep the body nice, I get it, but I still say have a consistent line front to back.

Click to expand...

Slander said:

I'm with you on the kick outs. Have seen them hang up more than help.

Click to expand...

I agree 100%, smooth transition is the way to go as I have learned this stops in your tracks.

I have an internal C and external C pillar. The original plan was an internal B and external B. Overkill? Yes/No. I’m only 1.75in .120wall on a 7k plus rig loaded (6500-6800 empty depending on door setup) the external B pillar must stay. If I didn’t have my external B my doors wouldn’t close, or seal. If I compromise strength on the external B with more bends at the bottom I can make up for it internally. In the end I don’t suspect a high speed rollover. I don’t get crazy in whoops. I am not in Moab/sand hollow often to fall off a 100ft ledge. I prefer being in the bottom of a canyon.

Lincoln said:

BS. You baited that poor animal hoping to get some cool bite marks or slashes on your ride. Like youtubzzzz, flakebook, twatter, or tic toc play with your cook cool.

It didn't care about your "likes" and now you're trying to salvage what you got.

Click to expand...

The drama is real, I could have died on that trail, hopefully this starts my new career as an influencer

It doesn't look like much. What about making the rocker wider for the whole length?

Lincoln said:

It doesn't look like much. What about making the rocker wider for the whole length?

Click to expand...

That's what I was trying to say

I could do that too. It’s probably an inch or so. Not much.

YotaAtieToo said:

That's what I was trying to say

Click to expand...

Apparently I'm a poor reader.

Lincoln said:

Apparently I'm a poor reader.

Click to expand...

That or I worded it poorly

I took the longer way out, instead of adding a tube across I cut out the stick out, then did a 21* bend to sweep it in on the slider. Knocked one side out last night after putting the baby to bed. I hope to do the other side another night this week

Why are you driving your speedo off the PCM at all? The 6L80E doesn't care about speed, just turbine speed changes.

You can wire in a VSS and direct drive it from the t-case. Want a Dakota Digital VSS that will do that?

Grendel said:

Why are you driving your speedo off the PCM at all? The 6L80E doesn't care about speed, just turbine speed changes.

You can wire in a VSS and direct drive it from the t-case. Want a Dakota Digital VSS that will do that?

Click to expand...

Is there an oem application that reads off the t case VSS with a 6l80?