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H3 Tranny dead

atvspeed4

Well-Known Member
Messages
1,211
Location
massachusetts
What do ya’ll think of a manual tranny? Would that be easy to pull off?


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Definitely not easy to pull off honestly much easier to get a properly built transmission shipped over to you.

We are putting a 6l80 in my alpha with a 6.OL but until there is a kit I would not say it's an easy swap. The 6l90 we are putting in our 2006 will only work with the shorter np241 due to torsion bar crossmember
 

humvee

Well-Known Member
Messages
507
Location
Doha, Qatar
So theres a salvage H2 (2008 model), flipped and going for parts.

I know it has the 6 speed 6L80 on there. To get that to work on my H3, I'm under the impression that I'd need to:

Buy an adapter
Respline the shaft
Get a harness with interface to communicate with my computer

I'd be interested to know your thoughts on this.
 
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humvee

Well-Known Member
Messages
507
Location
Doha, Qatar
Here are some images

Screen Shot 2018-01-19 at 1.22.59 PM.pngScreen Shot 2018-01-19 at 1.23.08 PM.png
 

atvspeed4

Well-Known Member
Messages
1,211
Location
massachusetts
All im thinking is:

Parts parts parts

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If you don't mind waiting a month for more info let me finish installing this new harness / programming we just received for our swap and I'll give you feedback. Hoping this actually works and is FULLY functional. The last swap on here drove but I know 100% had programming issue and wiring missing as I spoke to the original supplier in depth about the 4lo torque converter not locking and speedometer correction along with interfacing with the bcm. I would still not trust a 2008 6l80 as there were some issues that were worked out in 2010. Also, in stock form with the weight of our H3 and your HP you still might have issues.

Have you looked into a 4l85 swap? The first gear isn't as low but you really don't need that with your type of wheeling and HP. They already make a over the counter 27 spline output shaft and harness adapter from PATC. Lightly building a 4l85 is inexpensive common parts and can handle anything you throw at it even if you decided to add boost down the road.

With a 1" bodylift it should fit as we currently have a 6l90 in ours no problem.
 

humvee

Well-Known Member
Messages
507
Location
Doha, Qatar
I would still not trust a 2008 6l80 as there were some issues that were worked out in 2010.

Thats great advice, I won't go for something that isn't proven to work, and plus the H2 is no longer available.
I also know that if I'm sticking with 4 gears, then I have nothing bad to say about the 4l60, it was just a bad rebuild job.

I would consider the 4l85 if there is no alternative, but if I score a 4l60 off a 2009 Tahoe, Silverado or Sierra, shouldn't that bolt right on without having to gut it and swap the output shaft? Or am I mistaken?
 

atvspeed4

Well-Known Member
Messages
1,211
Location
massachusetts
Just to clarify, I have a stock 5.3 L engine off an H3 Alpha.

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Oh for some reason I thought you had a cam and tune. I believe the alpha 4l60e uses a special valve body for clearance. I have personally not tried to use a standard 1/2 ton 4l65e out of a yukon etc so I do not know if it will work.
 

humvee

Well-Known Member
Messages
507
Location
Doha, Qatar
yeah amrg has the camed LS3, I have his old 5.3

Well I do have the valve body, I know Chris swapped out the valve body when he put in the motor + tranny, trying to dig in to see if that was straightforward.

Chris if you're tuned in, your build threads need indexing and a contents page
 

humvee

Well-Known Member
Messages
507
Location
Doha, Qatar
I have personally not tried to use a standard 1/2 ton 4l65e out of a yukon etc so I do not know if it will work.

I found a 2011 5.3L Colorado, tranny's got 38k miles on it... Salvage.

Didn't come across anything that says this won't be a direct fit, what do you think?

Screen Shot 2018-01-20 at 7.33.23 PM.png
 

Ordieh

Well-Known Member
Messages
152
Location
Georgetown texas
I found a 2011 5.3L Colorado, tranny's got 38k miles on it... Salvage.

Didn't come across anything that says this won't be a direct fit, what do you think?

View attachment 23056
Still have to have the H3 pan and valve body. I have 2 spare valve bodies. A new ACDELCO and a VALVEBODY PRO rebuilt (both in unopened boxes) . GM has had them on backorder for a long time. If you get in a pinch, I could let one of them go but I don't have a spare pan. Best of luck!
 

humvee

Well-Known Member
Messages
507
Location
Doha, Qatar
All I’m thinking is:

Why? Why? Why?

(Just fix the 4L60)

I’m with you, but no one here is qualified for that, I’m getting 4k miles per rebuild, and its costing me as much as a used tranny each time. Down to the last straw with the wife.

Might as well try my luck with this one.
Hope it lasts.


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amrg

Well-Known Member
Messages
2,317
Location
Qatar
How the hell do you think I managed to pull my LS swap!!!

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humvee

Well-Known Member
Messages
507
Location
Doha, Qatar
Good stuff, will need to get creative when the snorkel comes on next week.

Alright, seals from rock auto... Here's what I have so far.

Crankshaft seal - ACDELCO29602
Torque converter seal - ACDELCO24202535
Output shaft seal - ACDELCO8677268
Dipstick seal - ACDELCO8677268
Retainer pack - ACDELCO 8654491

And also Oil pan gasket + filter + new bolts.. What am I missing here?


8677268_Primary__ra_p.jpg24202535_Primary__ra_p.jpg

296-02_Primary__ra_p.jpg1259475_Primary__ra_p.jpg8654491_Primary__ra_p.jpg
 
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CaseyS

Well-Known Member
Messages
755
Location
Louisiana
Is the pan on that transmission scalloped on the passenger side for the front driveshaft? If so you should be good. If not.....there is bad news in your future.
 

humvee

Well-Known Member
Messages
507
Location
Doha, Qatar
Is the pan on that transmission scalloped on the passenger side for the front driveshaft? If so you should be good. If not.....there is bad news in your future.

I jus asked him to send some more pictures, why do you say that? Please doo tell.

Wouldn’t I just be able to swap out his pan with my original Hummer3 pan?

This was a 4x4 model.


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4speedfunk

Well-Known Member
Messages
4,250
Location
Tardville
The H3 (and the C/C) are the only vehicles using the driveshaft on the passenger side. So the tranny pan (and internals inside) are special for them. A 4L60e from other GM vehicles won’t fit without swapping the valve body, filter, and pan. And of course you have to get correct bell housing for your motor.

I assume all the 6L80 tranny’s are from full size GM chassis’s, (drivers side shaft)...so it may not be as simple as converting a non-H3 4L60e to fit. Sounds like Atv is already on top of it.

Lastly..if you can’t find a qualified mechanic to rebuild the stock tranny, then I doubt if he will be able to pull off something as complex as a 6-speed upgrade. It’s way more work than a stock rebuild. Don’t be afraid to dive in yourself. Many of us have found that seems to be the best course. “If you want it done right...do it yourself.”
 
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