DIY transmission rebuild

[HUMMER H1]

my 1985 humvee has year 2000 H1 motor and transmission, 3700 hours of operation time since 2016,
On my last trip to Mojave desert my friends jeep got stuck in mud, I tried to pull him out, I got stuck myself and damaged the reverse band,

my humvee runs on Full manual mode, no TCU
I was able to drive home with all forward gears functioning,
It was time to rebuild the transmission.

I thought this can’t be rocket science to do the 4l80e
I have never done transmission before,
But I have PHD degree from YouTube
and few color books showing how to do it,

 

[HUMMER H1]

Now the first question someone may ask is
What a hell is a mud and water doing in Mojave desert right ?
haha yes there is a big river crossing there, few years ago water was over half way to the windshield,

anyway I took the transmission out myself,
It’s a few hours of work,
took it apart,
As you see it still has perfectly good forward clutches,
Those transmissions don’t get much abuse beyond humvees, they don’t get stressed, remember my truck has 3700 hours of operation time that’s equivalent of what 250.000 miles ? And i bought the motor and transmission used from predator Inc.

 

[HUMMER H1]

Reverse band it completely worn out,
Reverse band is used a lot if you pull out others in reverse NEVER EVER USE YOUR REVERSE TO PULL OTHERS .
Lesson learned, and after opening the transmission and rebuilding myself, I see why.
The entire load is on the band.

reverse band is also used a lot on low range 1st gear
Which I use all the time, this is why it’s worn out,

 

[HUMMER H1]

hardest part in rebuilding the 4l80e is keeping track on what goes after what,
Label label label video video every part you take out.

 

[HUMMER H1]

As you see in this picture
clean rebuild transmission is ready for the valve body to be installed

 

[HUMMER H1]

Huston we have a lift off
Rebuild transmission is back on the truck and driving as it should,
Next week I have a long trip coming up towards northern Nevada, I had to get the truck back on the road ASAP.


those transmissions are one of the best in the world and as simple as they come,
With YouTube PHD degrees, and some mechanical knowledge, anyone can rebuild one of those.

There you go,
Go have fun with your humvee

 

[HUMMER H1]

Oh I forgot,
When I finished the transmission I didn’t lineup the torque converter correctly
When I tried to put it on the motor i broke two of the side bolt mounts on the transmission,
I had to take it and get it welded,
( Charles TOBASH ) was there to help me with his knowledge,
But this is called collage tuition cost, going to school is not cheap, I learned how to rebuild one of the world’s greatest transmissions,

So what if I spent 300 bucks welding back broken transmission bracket,
I had a great time learning.

 

[HUMMER H1]

 

[TNDRIVER]

View attachment 942702
As you see in this picture
clean rebuild transmission is ready for the valve body to be installed

Sonnax makes a few items that can improve the durability of the 4l80 also. Just in case you have to open it up again NMWR 9-2520-582 might help. NICE work!

 

[HUMMER H1]

Sonnax makes a few items that can improve the durability of the 4l80 also. Just in case you have to open it up again NMWR 9-2520-582 might help. NICE work!

Thank you very much sir, that’s really helpful PDF link

 

[TOBASH]

Just to clarify, General motors torque converters need to be spun and click/clunk into position. Typically they click or clunk into position three times and after that, it is safe to install the transmission. In Eric‘s case, the final clunk did not occur and Eric needed to remove the Pump and machine the damage he caused by trying to mate the transmission to the engine with the torque converter proud by 1/2 inch.

When reinstalling a GM torque converter, always keep twisting the torque converter until it fully seats. You’ll feel three clunks and it should fully seat so that there is at least 7/8 of an inch between the rear end of the torque converter and the bell housing flange. Another way to check is to look at the torque converter to ensure that the front of the torque converter, the polished and burnished metal that is supposed to be seated and hidden, is not sitting proud. The third check is to measure the distance between the engine and the rear surface of the flywheel, and then measure the bell housing and the forward surface of the torque converter, and if those measurements are not in order you have not properly installed your torque converter and you need to deal with that otherwise you will damage everything.

Eric did an amazing job. Eric is correct that everything is a learning experience and he has the correct attitude. He just gets her done and moves on.

 

[Dieselmeister]

Thank you for your post. This gives me the encouragement I need, to try to fix my minor issue (Minor I hope). I just developed a mystery transmission leak I need to fix. Appears to be coming out between the x-mission and transfer case. I suspect the x-mission rear seal is leaking.

 

[HUMMER H1]

Thank you for your post. This gives me the encouragement I need, to try to fix my minor issue (Minor I hope). I just developed a mystery transmission leak I need to fix. Appears to be coming out between the x-mission and transfer case. I suspect the x-mission rear seal is leaking.

Oh yes that seal is super easy Fix, all you need is large snap ring remover from harbor freight,

take the TCase out and remove that seal.

there are 7 or 8 bolts holding the transfer care attached to transmission, 14 mm,
It’s probably two hour job or less.

 

[FlameRed]

You sir, have some real chutzpah!

Wrench turners like me could take it apart, but never in a billion years, get it back together - let alone have it work properly!

 

[Mogman]

Oh I forgot,
When I finished the transmission I didn’t lineup the torque converter correctly
When I tried to put it on the motor i broke two of the side bolt mounts on the transmission,
I had to take it and get it welded,
( Charles TOBASH ) was there to help me with his knowledge,
But this is called collage tuition cost, going to school is not cheap, I learned how to rebuild one of the world’s greatest transmissions,

So what if I spent 300 bucks welding back broken transmission bracket,
I had a great time learning.

Unfortunately you may have damaged the pump by not having it aligned correctly, hopefully not.

 

[Dieselmeister]

You sir, have some real chutzpah!

Wrench turners like me could take it apart, but never in a billion years, get it back together - let alone have it work properly!

Just remember - It is already broken when you are trying to fix it. So you can'r really break it. The fun part of doing your own repairs is that you get to learn how things are put together, and how thigs work.

 

[HUMMER H1]

Unfortunately you may have damaged the pump by not having it aligned correctly, hopefully not.

No damage
Yesterday I have put about 160 miles on the truck,
All normal ,

 

[HUMMER H1]

Just remember - It is already broken when you are trying to fix it. So you can'r really break it. The fun part of doing your own repairs is that you get to learn how things are put together, and how thigs work.

And to add more,
When you learn how to fix your truck, it gives you even more confidence to go enjoy the heck out of it,
When I bought my first H1 in 2003, I had no clue about those vehicles,
Today I can point a bolt on the ground where it belongs on the humvee,
22 years of playing with them and fixing those vehicles equals to confidence on long distance trips,

I expect no less than 400.000 miles out of my truck.