TH400: 4L80E Drum Retrofit

[@Daniel-Johnson]

Shawn I about died laughing at the " From the camera angle I should lay off the cake tonight " Comment 🤣🤣 I am right there with ya buddy, I have contemplated my own youtube channel but no one wants to see my beer belly bouncin around in a video lol

[@djrowe10]

What's crazy is since this video a few years ago the 34 element drum and aluminum th400 piston has increased in price by 500%. I bought the drum for $35 and piston for $20 for 2 decades. The drum is $250 now and piston is $100. Lets go Brandon!

[@mountainsgarage]

So true!

[@jakestree1892]

Great video and instructions

[@smbaker84]

man i'm glad i happened upon this channel. so much good solid info. sub'd and watching all i can. awesome work man.

[@mountainsgarage]

Welcome aboard!!

[@shannonleonard3317]

Awesome man doing my th475 with a 1-2 brake also great information

[@quartermilejunkie5439]

Great video

[@BigFun4Life]

Another great informative video,thanks for sharing......Keep them coming Shawn...

[@mountainsgarage]

Thanks!

[@skywaves5175]

Another wonderful video you created. My son and I are working on a th475 for street use for a 55 two door post. I just like watching as many video to get as many building tips as possible. Thanks for taking the time and spending money to make those videos and share your knowledge with us.

[@mountainsgarage]

Great father/son project! Glad I could be a small part of it!

[@brentonk461]

TWANG, Ting Ting, ting.. Don't you hate that 😁👍

[@SS454JF]

Where i live in el paso Tx, we have no H..p trans builders worth anything. Your vids are very informative.

[@mountainsgarage]

Thanks!

[@jeffyoung2089]

Thanks!

[@sewerpipecasso8750]

So entertaining. Good stuff. Keep em coming. How’s the nova doin

[@mountainsgarage]

It’s chilling on the lift waiting, Thanks for watching!

[@BigMikesGarage]

What are the part numbers on those Kent Moore seal tools? Thanks for continuing to provide quality info!

[@mountainsgarage]

I will get them off the tools if I can still read the numbers. They are listed in the ASTG manual also.

[@brentonk461]

use a cobalt drill bit mate. Try that.

[@craigjrose2227]

Thanks for you great videos, Where can i find a4l80e drum kit to send to Australia? Thank in advance

[@waynebillings2913]

IT LOOKED LIKE THE PISTON YOU CUT WAS BELOW THE GROOVE IN THE BOTTOM OF DRUM.

[@mountainsgarage]

No, must be an optical illusion. Always check that!

[@tomscobra2003]

Hey Shawn , is the 4L80E main shaft the same as the TH400 trans

[@funfun8095]

👍👍

[@jesusm2797]

Question, so no mods needed to run a 4l80e drum in a th400 if it does Not have a trans-brake, the th400 only has a shift kit to give it the ability to hold each given gear

[@tommysteadman1547]

Shawn, I'm looking to buy the j tool for installing the outer lip seal for the drum # J21409 but I'm wondering why the 4l80E tool J38732 wouldn't work since you use the th400 tool in the 4l80E drum? Any help with this would be greatly appreciated. Love your videos, keep them coming. Tommy

[@mountainsgarage]

The inner and outer direct seals and pistons interchange so should the tools.

[@tommysteadman1547]

@@mountainsgarage That's what I was thinking, not sure why they are different part numbers? The inner seal tool number is the same though. Thanks for your help and quick response. Keep up the good work. :) Tommy

[@TheEinart]

Another great video, i have a question also, im rebuilding my th400 (375) and i replace the piston in the direct drum so i could use 6 new clutches and steel, i bought new springs and threw them in all. the 400 goes in to my fullsize bigblock olds with some nice torque. but when i think back i installed the inner lip seal just as stock. but should i remove it again, and i see in the th400 manual it should be only 12 springs than 14. i guess in a stock setup, but any small upgrade will be good to me,so i was thinking to just leave the 14 piston springs as they are.. this is just a stock valvebody for now. any suggestion if i should mod the direct drum? i will use the stock blue oil pump spring. thanks.

[@mountainsgarage]

It’s a good time to dual feed the direct clutches by leaving out the seal on the direct drum, the second seal from the top of the center support, and blocking the right hand feed hole viewing from the bottom rear in the case next to the center support bolt. I run springs in all positions. Thanks for watching!

[@TheEinart]

@@mountainsgarage Thank you so much, i will try that 😃

[@jeepgodfabrication9970]

Hey Shawn. How long do you figure a fresh transmission can sit before being used if it was probably lubed when built and stored inside

[@mountainsgarage]

I lube the raw metal surfaces with 3/36 or WD40 to prevent rust. I have seen the factory GM transmissions sit in their black box for decades and still look new.

[@kevindrury8390]

Thinking of putting one in my 375. Just use it like it came. Just automatic shift. Where do you get your drums? Thanks

[@mountainsgarage]

I bought these on eBay for $100 each two weeks ago. They seem to be $129 now.

[@TheEinart]

What thickness of steels and clutches whould you prefare for the intermediate piston for a streetcar with a 4l80e direct drum in the th400? im rebuilding right now and those steels i had was so burned, and it had only 3 clutches, so was thiking to buy new steels and clutches to fit up to the 4l80e sprag. Thanks for any ideas :)

[@djrowe10]

I see he didn't answer you so I will answer your question. Even with a 4L80e direct drum you should still only use 3 x 0.100 thick steels and 0.95 thick frictions. The 4L80e uses 4 frictions and steels but all are thinner then the th400, which is partly inferior for heat soak. GM THM modified the 4L80e late in 97-98 and that changed inner dimensions making interchange parts with th400 partly obsolete except the drum. The 4L80e is the same internally from output shaft to direct drum from 1991-1997. If you have an older 16 element th400 drum you can just add the 34 element sprag.

[@gregorysteele628]

You mentioned 4 clutches for the intermediate clutches. How's that work on the 400 anything special to do to make this work ?

[@mountainsgarage]

Check out two videos back, “How it works II” at the 6:45 min mark, it’s covered there.

[@suicidal_racing]

im in the middle of doing a th400. a 4l80e drum then i got a ck performance rmvb (none t brake) an when it says to do the dual feed mod in his directions it just says pull the inner lip seal but nothing about a high speed hole. should i still do the speed hole? i believe in one of your other vids you had said you have used their vb before. thanks for your time an help

[@mountainsgarage]

Yes drill the 1/16 hole in the direct drum, always a good mod.

[@suicidal_racing]

@@mountainsgarage thanks for the info. I just wasn't sure with his vb. It looks like everything with his vb is done via the separater plate being the 1-2 shift hole isn't blocked an as you know trying to talk to them or get a hold of them is basically not happening.

[@stevenslater2669]

I’ve noticed that some trans builders soak the clutches in trans lube before installing. You put them in dry. Any comment?

[@mountainsgarage]

I mentioned I would soak them on final install. I lower the drum into the transmission without them so I can grab ahold of it.

[@raulh802]

What if I’m just installing a manual valve body , do I need the super duty springs and drill the hub ?

[@mountainsgarage]

The springs are for transbrake release, drilling the bleed hole is always a good idea.

[@scottstoneburg8722]

Do you have a part number and manufacturer for the piston install tools you used. ?

[@mountainsgarage]

They are Kent Moore. The numbers are in the ASTG manual.

[@keysautorepair6038]

Off topic but can you take out the th400 governor and put in a governor delete plate on the th400 with a transbrake.

[@mountainsgarage]

Yes it is one of the install steps. I turn the governor cover around backwards and install it, no question their is not a governor present. The billet covers are nice and only $13 ish.

[@keysautorepair6038]

@@mountainsgarage I had a transmission shop down the road say that you couldn't do it he built my transmission that lasted about 3 passes and blew up he left the second sealing ring on the center shaft put cast iron rings on it had 120tho in both drums 4 cluches in the forward 6 in the direct drum 150th in the intermediate cluches I'm not sure he knows what he was doing lol I'm building it myself now like I did the first time it lasted 4 years I find your videos very helpful thanks.

[@lockshoprobert]

Can you make this modifications and not use a trans-brake. I have a Pontiac 400 in a 69 GTO that I'm planning to stoke the motor at first and late add nitrous or a turbo system. When i rebuild the trans I would like to make it as strong as possible. This will be street car and not a drag car but may take it to the track some times.

[@mountainsgarage]

Yes you can. The drilled 1/16” hole is always a good idea to prevent centrifugal apply of the clutches.

[@lockshoprobert]

@@mountainsgarage Thanks!! I was house bound yesterday so you help pass what would have been a very boring day. I found your video's very educational, informative and entertaining. You have give me the inspiration to do a future transmission project. I'll have to start gathering parts for it. I watched hours of your videos.

[@mountainsgarage]

@@lockshoprobert Awesome! Glad to help!!

[@petermullin5387]

Why can’t you drill the bleed hole from the other side of the drum with a drill press?

[@mountainsgarage]

Because that would be too easy and make sense! :)

[@petermullin5387]

@@mountainsgarage as 2 former Municipal Employees should be ruled out automatically.

[@jeffharrington5789]

I imagine this holds true for a 4l80 also?

[@mountainsgarage]

Yes

[@mrrobot545]

i'm interested to know what lip seal tool that is?

[@mountainsgarage]

Which one?

[@mrrobot545]

@@mountainsgarage the one that fits down into the drum has a big circle and then a smaller circle for the inner lip seal.

[@GrandpaMelancon-hm2mk]

May I call you