Hummer H3 Build

[CDA 455 II]

06h3
I have a request:
When you get the rig back together; may I stop by and get a ride in it?😇

I would like to know what 110:1 drive ratio feels like from an auto (vs a manual).
I've never experienced drive ratios more than 40:1 from an auto.

 

[06h3]

06h3
I have a request:
When you get the rig back together; may I stop by and get a ride in it?😇

I would like to know what 110:1 drive ratio feels like from an auto (vs a manual).
I've never experienced drive ratios more than 40:1 from an auto.

Absolutely!! I’ll let you know when it’s done. The PCM/TCM should arrive at the tuners this week, he’s on the edge of Canada and the US so Canada shipping slows things up. I’m guessing a few weeks before it’s driving

 

[CDA 455 II]

Absolutely!! I’ll let you know when it’s done. The PCM/TCM should arrive at the tuners this week, he’s on the edge of Canada and the US so Canada shipping slows things up. I’m guessing a few weeks before it’s driving

Awesome; thanks!

 

[fl0w3n]

Yeah, I asked him. I still have AC though so I don’t think it will work

I text my old Duramax tuner to ask and he said it should be pretty easy to do it a "hacky" way - since you're DBW, setup a valet mode switch that limits RPM to 2k or whatever you want for running the welder. Then in park just throw a brick on the throttle and it'll only go to whatever RPM you set. Basically what you're doing already, but instead of finding just the perfect stick or rock to get the throttle where you want it, you just need to mash it and it'll hold the RPM you want.

He also said you could look into custom OS, maybe someone has incorporated the PTO logic from the Duramax/Allison setups into the LS OS.

 

[Chkn]

How did you decide who to send the ECU too? I just picked up a 6L80 and and have a 4.8l to go in my Landcruiser but not sure who to have do the programming to make it possible.

 

[06h3]

How did you decide who to send the ECU too? I just picked up a 6L80 and and have a 4.8l to go in my Landcruiser but not sure who to have do the programming to make it possible.

In my personal case it’s a guy that was on the Colorado forums doing harnesses. I have heard good things, reached out and had him do my 5.3 harness and programming. I had a positive experience and have probably sent 10 others to him in the hummer world.

He said he can do a 6l80e setup as well. I like using him and think he’s good for the Colorado/hummer platform.

Depending on what your doing may help lead you into the right direction. Stand-alone, integrated, etc.

 

[Chkn]

In my personal case it’s a guy that was on the Colorado forums doing harnesses. I have heard good things, reached out and had him do my 5.3 harness and programming. I had a positive experience and have probably sent 10 others to him in the hummer world.

He said he can do a 6l80e setup as well. I like using him and think he’s good for the Colorado/hummer platform.

Depending on what your doing may help lead you into the right direction. Stand-alone, integrated, etc.

Mine would be basic standalone. VATS delete, rear O2 delete, EVAP delete but otherwise factory tune.

 

[06h3]

For something like that I don’t think you have to be too picky on a tuner. Just use one that knows what they are doing. I think a tuner matters more when it’s more complex for factory integration

 

[06h3]

Been slow going, worked on it a couple hours last night and tonight.

I pulled a bunch of wires, pinned them out and got them labeled and wired in. Basically it’s all wired to run and drive. I just need to loom it up. The one final thing I still want to do is wire in tap shift. I have resistors that should get here tomorrow.

I also disconnected the tcase and trans so after tap shift wiring I’ll start on swapping inputs

 

[06h3]

I bought a 32 spline wide bearing input because I thought I had a wide input bearing. Of course it was a narrow bearing that stopped my progress on tcase work. Luckily bowman trans is about an hour from me. I messaged him and he’s got plenty of both wide and narrow bearing inputs. I figured he would since he builds a ton of doublers and off-road racing transmissions so I’ll spend a couple hours this morning going to get the input.

The progress I made was I pulled vacuum on the hummers AC unit so it’s ready to fill. After 40 min of pulling vacuum I only achieved 24-25 lbs of vacuum. Any AC experts here? I hear for ac systems you should pull around 29 lbs. does elevation change that? I am at 2700ft elevation. I checked it after leaving it overnight and it’s still 24-25 lbs of vacuum so there’s no leaks

Here is my t case support bracket. The 4L60E and 6L80E are the same length but the tail housing is about an inch shorter so I had to shorten my bracket as you see it won’t fit. (Tail housing is a part of the trans but unbolted from it for modification)

I did this years ago because bowman trans recommended it. He said it was a ton of weight to hang off the the back of a trans even with the rear 205 support. So this bracket attaches to the removable tail housing on the trans and sandwiches between the trans mount and tail housing and attaches at the 3 unused figure 8 pattern 205 bolts.

Here is is shortened up. Just gotta weld it together.

Also drilled out and tapped the drain plug for 1/2 NPT. The 3/8 NPT threads got buggered up and were leaking. Glad I got this taken care of.

Off to get the new input and hopefully get the doubler finished today. Process will be minimal this weekend as I’m helping a friend drive/transport his Duece and a half 320 miles from his dads house to his house. Wish us luck, hasn’t driven in 5 years!

 

[CDA 455 II]

06h3
Is that Bowman Transmission and Offroad in Mountain Home?🤔

 

[06h3]

06h3
Is that Bowman Transmission and Offroad in Mountain Home?🤔

Yeah, cool dude. Very very knowledgeable and in my opinion, he has the most proportional looking rig on 54s

 

[Chkn]

Altitude does affect pressures when doing AC work. 29inHg would be at sea level. I don’t think you will have any performance issues at 25inHg especially when you don’t have any leaks in the system. All of your moisture will be boiled off and it should run good.

 

[06h3]

Does anyone have experience with 6L80Es? Should I throw a TQ converter in it before slapping it in? Bowman was telling me they are the weak links from the factory.

 

[Midget]

Yes put a converter on it. The factory torque converters suck. The ATSG had an article awhile back about the front covers flexing/wapring and causing problems with the linings and taking out the pump. The jist was to use a quality billet front cover converter to alleviate a lot of the issues found with warped covers and damaged linings.

A good TC will also improve shifts, reduce heat in the fluid, and prolong the life of your transmission.

 

[06h3]

Progress has been slow, I was out of town the last 2 weekends helping a friend move a Duece and a half and then camping the other weekend. I was also out of town for work during the week but I’m back at it.

I still don’t have the pcm/tcm yet.

I got the right input with the correct bearing width so I put that back together. the input snap ring seems to have lost its spring pressure and is loose! I ordered a new one, I’d take my chances if it was something more accessible but given it would require pulling the driveshafts, t case, etc. it wasn’t worth it and I’m still waiting on parts.

You can see the small gap between the shaft and snap ring on the left.

I assembled my Yukon super joints into the chromoly shafts.

I broke 1 u joint in 5 years which wiped out a factory 35 spline inner and 35 spline outer, I’m hoping this will hold up for much longer.

I also installed the new 6l80e shifter shaft, this is a genius idea and a new product so you probably haven’t seen it before.

This is totally unnecessary for non GM factory integrated builds but for GM vehicles swapping in a 6l80e you historically had to do all sorts of relays and wiring to get the reverse lights to work and the gear indicator light on the dash.

Those 2 functions were done off the transmission range switch which the 6l80 doesn’t have. This shaft is slightly longer and machined/indexed to just slap a 4l60 transmission range switch on a 6l80 plug the old plug back in on the range switch and bam, you have those 2 functions back without all sorts of tricking the computer and added relays/wiring. 2 roll pins and it’s out, then put the new one in.

Todays project is bringing tap shift wiring up to the cab and swapping out the rear main seal.

 

[06h3]

Do we have a 6l80 guru in here?

I can post up the info later of last weekends work of getting the trans in and stuff but right now I’ve got other crap to figure out.

Tuner emails me the vin from the trans so I have a reference for hard parts if I need them in the future.

I do a vin look up and sure enough the fucker I bought it from lied to me, not 90k on it, it’s got 160k on it. I bought it 2-3 years ago so there’s no tracking him down now. I also told him I need it to work with an 08. He said its 07 and 07-08 work together.

Well 07-08 was true, they do but in my case I got unlucky. it was an 07 but it was such an early 07 that it was built in 06 and for a short time they had tcms that were 06-07 specific, not 07-08. The tuner said he doesn’t like to do this but changed the vin in the tcm to a later model. He used an 09 vin. It accepted it and now my pcm and tcm are talking. His fear is that the 09 tcm controls may be different because there’s different hard parts or internal things that may not jive with an 06-07 trans and an 09 tcm.

I guess I can ask him to try an 08 vin but same potential problem. Maybe it won’t jive with an 06-07 trans. Does anyone have insight on year to year changes?

 

[06h3]

Ok progress has been minimal as I was waiting on parts, TCM and PCM will be here today according to USPS. We think we got the problem figured out on the 07/08 TCM questions.

I made a bracket for my Transmission range switch from the 4l60e. I had to cut up the range switch bracket a little bit but this should cover me for reverse lights, neutral safety switch and PRNDL indicator on the dash.

I got the radiator, trans cooler and front end all buttoned up.

I bypassed the pusher fans this time around. I used to have pusher fans for slow speed crawling but since my new radiator has a capacity of 1.6 gallons and the old one was 0.7 gallons, I hope I can bypass it. Technically I didn't need it much for the coolant but more for the trans fluid. Either way, since the radiator is bigger, I would need to redo a bunch of crap to get the fans in and do not know if it is necessary. I am trying to decide if I should run the trans cooler lines in through the radiator. I bypassed it years ago because I was nervous of a leak and mixing of the 2 fluids together but this is aluminum and I hear good things about it so I may loop it back in. Thoughts?

I also added some plate to the core support where I took material out.

t case is back together.


Just waiting on exhaust parts and then I can stab it back in and go for the first test drive.

Tap shift wiring is run into the cab but still need to finish wiring it in. I may wait until its driving to do that so I can isolate any problems one at a time.

 

[Lincoln]

The radiator cooler will help the transmission warm up in the cold. I was told to run a thermostat if the radiator was bypassed.

Looks good!

 

[06h3]

It's almost been a month since the last post. It was slow going, my wife is pregnant with our first child and during the first ultrasound they found a tumor on her appendix, so it had to come out, they said it would cause implications in the 3rd trimester. She had it taken out a few weeks ago so I was tending to her and the surgery. Everything went well and part of the reason I am trying to do a 6l80 swap and link the rear of the hummer before December is because I am sure my free time and disposable income will dwindle by then. On the bright side all my buddies are building family friendly rock crawlers since they had 2 seater Jeeps and toyotas and now have kids. I luckily have a solid family rig already built.

Anyways, I went for my first test drive and it was a success! The high mileage 6l80 shifted into all 6 gears and locked up the TC. I think extended highway time will really show the value of the 6l80 but even driving around town it effortlessly accelerates with light throttle input since it is in the powerband so much more with the added gears.

I have the exhaust about 70% finished. I needed to modify it so I can fit the trans and I got it finished enough to drive it, yes, I am impatient.

The trans shifts kind of sluggish. I am assuming I can tune it to be firmer.

Tap shift is giving me an issue so I still need to figure that out. AC needs to be recharged. I will get pics up soon.

 

[Billybadass411]

Congratulations!

 

[06h3]

Congratulations!

Thank you!

 

[350TacoZilla]

Just read through, sweet rig man. For future reference would you mind listing who made that shifter shaft? If you did sorry I missed it lol.

funny seeing 4 speeds were enough for 20 years then suddenly 6....8.....10, here soon the new trucks will sound like semi truck with all the shifts, fast and furious was just running future tech with a 18spd swapped charger

 

[arse_sidewards]

Just read through, sweet rig man. For future reference would you mind listing who made that shifter shaft? If you did sorry I missed it lol.

funny seeing 4 speeds were enough for 20 years then suddenly 6....8.....10, here soon the new trucks will sound like semi truck with all the shifts, fast and furious was just running future tech with a 18spd swapped charger

I get having more overall spread with the same splits but a lot of the newer stuff is just silly emissions and fuel economy optimization. A car with fancy modern engine with VVT, variable intake, direct injection and a resulting dyno curve that has a hosepower plateau through most of it won't be made any faster by adding a bunch of gears with 500rpm drops.

 

[06h3]

Just read through, sweet rig man. For future reference would you mind listing who made that shifter shaft? If you did sorry I missed it lol.

funny seeing 4 speeds were enough for 20 years then suddenly 6....8.....10, here soon the new trucks will sound like semi truck with all the shifts, fast and furious was just running future tech with a 18spd swapped charger

Thank you! The shifter shaft is sold by Zero gravity performance in AZ.

I get having more overall spread with the same splits but a lot of the newer stuff is just silly emissions and fuel economy optimization. A car with fancy modern engine with VVT, variable intake, direct injection and a resulting dyno curve that has a hosepower plateau through most of it won't be made any faster by adding a bunch of gears with 500rpm drops.

I agree. I think there is a point of no return. I think the more HP you have along with the broader your torque curve is the less gears you can get away with. I think a 6 speed is a happy medium between new and old. An 8 speed probably works in rock crawling if the shift strategy is on point. If not I’m sure it’s a bit much.

I see the benefit to a 10 speed in a diesel (or gas) tow rig where you want to tackle a 5 mile grade at a certain speed and the trans can put you and hold you in that very specific gear with that specific load. Most 8-10 speeds are skipping gears all the time. I have personally driven a 10 speed expedition that goes from 8th to 3rd if you floor it. In a wheeling situation in tap shift mode I don’t think you can drop 7 gears fast enough.

I hope the 6 speed isn’t too much off-road and I see the benefit. I know I’ll see the benefit on road. I don’t question on road benefits one bit

 

[fl0w3n]

Congrats and good to hear your wife’s okay.

The difference in fuel economy between my 15 and 21 6.7s with the 6 and 10 speeds is 3-4mpg so not complaining there. Towing wise hard to compare with the 21 having been turned up hot from the factory, obviously big improvement. I hated towing with my old 6.0/4L80 rig, it needed a 6 speed for sure.

It seems pretty clearly the 6L80 will be better everywhere else, so I’m interested to hear how it’ll be crawling.

 

[06h3]

Congrats and good to hear your wife’s okay.

The difference in fuel economy between my 15 and 21 6.7s with the 6 and 10 speeds is 3-4mpg so not complaining there. Towing wise hard to compare with the 21 having been turned up hot from the factory, obviously big improvement. I hated towing with my old 6.0/4L80 rig, it needed a 6 speed for sure.

It seems pretty clearly the 6L80 will be better everywhere else, so I’m interested to hear how it’ll be crawling.

Thanks, that doesn’t surprise me one bit, I hate my 4 speed on my tow rig and my 4 speed was ok at best during certain time periods of my H3 build. Revving or bogging is the life of a 4 speed.

 

[Grendel]

In my personal case it’s a guy that was on the Colorado forums doing harnesses. I have heard good things, reached out and had him do my 5.3 harness and programming. I had a positive experience and have probably sent 10 others to him in the hummer world.

He said he can do a 6l80e setup as well. I like using him and think he’s good for the Colorado/hummer platform.

Depending on what your doing may help lead you into the right direction. Stand-alone, integrated, etc.

Send me that info, please. I have an LH6/4L60E harness I want done.

and I still go back and forth on the 4L60E vs a 6L80E.... I own the 4L and bought all the Alpha stuff for it.

Can you driveshaft clearance a 6L80E with stock stuff like a 4L60e

 

[06h3]

Send me that info, please. I have an LH6/4L60E harness I want done.

and I still go back and forth on the 4L60E vs a 6L80E.... I own the 4L and bought all the Alpha stuff for it.

Can you driveshaft clearance a 6L80E with stock stuff like a 4L60e

I had more clearance on a factory 6l80e over the special “high clearance” h3 special 4l60e

His email is [email protected] he only works via email

 

[Grendel]

I had more clearance on a factory 6l80e over the special “high clearance” h3 special 4l60e

His email is [email protected] he only works via email

Thanks, I have a D300 and no doubler though.