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Anyone Swapped This 6 Speed 4L80e

Hummer Guy

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https://www.ebay.com/itm/202148957760?epid=252098858&hash=item2f11044e40:g:pCQAAOSwsYpaNAy9 I been seeing these 4l80e 6 speed around, has anyone ever put one of these in the humvee? Seems like it should be a simple bolt in if you already have a 4l80e humvee, and you're like me & perfectly fine with the engine power but think the transmission is holding it back. This seems like it would be the answer to that without having to do too much work & fabricating to fit in a different size transmission like an Allison.
 

mgFray

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I assume bolt pattern, input shaft/torque converter, need to match the Detroit Diesel. So be aware that any old 6 speed won't necessarily "fit" without some sort of adapter.. maybe multiples.

There was another thread in the hotrod section talking about putting in a a 6-speed. Might be a good place to start looking.
 

FlameRed

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I am nothing close to being an expert so rely on the collective of experts here are they know their stuff. All I wanted to mention is that there is a sticky at the top of this forum regarding this subject: https://www.steelsoldiers.com/threads/lots-of-questions-about-4l80e-swaps.152874/ that has a lot of good info.

This is definately one of the projects I want to do also. A friend of mine outlined some of the alternatives to me, but I did not write them down. The alternatives varied widely. Next time I see him I'm going to ask him again and this time record his wisdom. He swapped the engine from a 6.2 to a 6.5 with the tranny himself.

I'm kind of on the fence about doing this project myself. In a few months I plan on retiring so I will definately have the time to do this, but I won't have the $ anymore. So I'll have to do it on the cheap which is an oxymoron with the HMMWV as I have learned. I never swapped a tranny, but I think I could since the HMMWV got so much room so I won't need a lift but I have special jacks that could lift the tranny up for me. At one point I was thinking about farming it out to one of the well know shops that deal with Humvees here in Florida but again, I won't have the $.
 

Mogman

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Look at the ratios, it is just a close ratio 4l80 6 speed, the top two gears are the same on both transmissions. does not look useful in the HMMWV it would shift up very quickly through the gears that the 4l80 already shifts up through very quickly, not at all like the 6L80.
It does have a lower 1st, would be better for extreme rock crawling which the HMMWV sucks at anyway.
EDIT, basically it splits gears 1 and 2 into 4 gears, when you hit 5th and 6th it would be the same as 3rd and 4th in the 4l80 where you could use and the 6L80 has closer ratios, certainly not worth the money they are asking IMHO for this application
 
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Mogman

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It also SEEMS their claim as the only 6 speed that can handle 850HP is BS.

And $2500 less at that
 

Hummer Guy

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Look at the ratios, it is just a close ratio 4l80 6 speed, the top two gears are the same on both transmissions. does not look useful in the HMMWV it would shift up very quickly through the gears that the 4l80 already shifts up through very quickly, not at all like the 6L80.
It does have a lower 1st, would be better for extreme rock crawling which the HMMWV sucks at anyway.
EDIT, basically it splits gears 1 and 2 into 4 gears, when you hit 5th and 6th it would be the same as 3rd and 4th in the 4l80 where you could use and the 6L80 has closer ratios, certainly not worth the money they are asking IMHO for this application
Yea make sense, I just saw the ratios. You're right, at the end you'll still be getting the same top speed. Another one I heard about was one from Phoenix Hummer Repair. They were making a 6 speed kit that simply bolt in, they have 2 videos of it on their youtube channel but haven't release the kit yet.

 

Mogman

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They have been working on that ever since I installed the 6L in the Detroit, at least they have a working model now.
 

Mullaney

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https://www.ebay.com/itm/202148957760?epid=252098858&hash=item2f11044e40:g:pCQAAOSwsYpaNAy9 I been seeing these 4l80e 6 speed around, has anyone ever put one of these in the humvee? Seems like it should be a simple bolt in if you already have a 4l80e humvee, and you're like me & perfectly fine with the engine power but think the transmission is holding it back. This seems like it would be the answer to that without having to do too much work & fabricating to fit in a different size transmission like an Allison.
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Just want to chime in and agree that this is a lot of work for no benefit on a HMMWV. Agree with @Mogman that with the same "last two gears" being identical to the 4 speed version. You won't be going any faster with the swap.
 

Mogman

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Interestingly enough the only difference between the 5 speed Allison 1000 and the 6 speed is the valve body, seems you can mix and match the clutch pack application for different ratios.
If you have an earlier GM with the Dmax and a 5 speed about $2200 (10 year old price) for a new valve body and TCM and you have a "higher" final gear.
I have no idea what these guys are doing though.
 

Maxjeep1

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Bigger tires! Get some 42’s and you have overdrive…. Cheaper and looks way cooler than a transmission. That kinda of money and you can have body lift and suspension lift and huge tires. Hahahaha that’s my path and it’s not for everyone. I will put a Detroit locker in the rear also…
 

Maxjeep1

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I don't think everyone thinks 42s look cool, if you have a 4L80 you already have overdrive, but if you have a turbo and the 307 gears bigger tires are about your only choice besides new diffs.
3.07- 42’s? Gets you m1123 gearing? I don’t know that’s why I ask. I believe everyone thinks 42’s look cool but some of the purest can’t admit it… I would like to have 40’s but with 16.5 your choices are so limited.
 

Mullaney

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I don't think everyone thinks 42s look cool, if you have a 4L80 you already have overdrive, but if you have a turbo and the 307 gears bigger tires are about your only choice besides new diffs.
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I think it has something to do with age.

Remember when the big fat tires on the back of a Camaro or a Mustang was "the thing"? We did it. Now days, bigger fat tires are just all the rage.
 

Maxjeep1

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I think it has something to do with age.

Remember when the big fat tires on the back of a Camaro or a Mustang was "the thing"? We did it. Now days, bigger fat tires are just all the rage.
Hahahaha. I still haven’t changed. I like small rims and lots of sidewall. I love old school so much… brings back better days.
 

Hummer Guy

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Bigger tires! Get some 42’s and you have overdrive…. Cheaper and looks way cooler than a transmission. That kinda of money and you can have body lift and suspension lift and huge tires. Hahahaha that’s my path and it’s not for everyone. I will put a Detroit locker in the rear also…
Good idea, but wouldn't that still rub and how does the humvee does with a suspension lift? I have the 2 inch pucks for that but never installed them. The biggest I'll go for tires is 40s. Even at that, I still like my tires to be flushed with the body
 

Maxjeep1

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Good idea, but wouldn't that still rub and how does the humvee does with a suspension lift? I have the 2 inch pucks for that but never installed them. The biggest I'll go for tires is 40s. Even at that, I still like my tires to be flushed with the body
I believe as long as you mount your tires on the oem rims you will be just fine. My m1165 is higher than my m1123. I don’t know what they should be and I only know what I got. I would like to do a spring spacer and a 2” body lift. I’m still in the thinking phase. Probably 39.5 is what I will settle on. I worry about putting body lift on these newer trucks. I see ac lines and stuff everywhere.
 

DaneGer21

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If I had the budget, I would do larger tires AND that transmission swap. Why? Well, we all know big tires can lug you down and rob “power” but gain higher top speed. So why not swap in that trans, and the larger tires. The closer gears(ratios) will help combat the large tires for city driving, mpg’s and acceleration, all while gaining a slightly higher top speed.

I don’t have an hmmwv, just thinking in “theory”…
 
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