[Half-Inch Stud]

I'm fixing to find bravery to put a 4L80 into my 68 GTO.

Need Driveshaft purchase
Need longer speedo cable (yea I got a speedo gear in the tail cup.)
Adapter plate for block all set.
flexplate drilled for 6-bolt converter all set.
Vacuum modulator all set (yea, did that too)
Manual shifter mounted to tail (yea again, it's awesome...)

--> Unknown floor tunnel fit! Anybody know from doing, if the 4L80 will fit?

[Sirrotica]

Mark, step by step in 67 Chevelle, shows using a small body hammer to get clearance for the output sensors (which you're not using because you went with the full manual setup). It's just a few raps with a hammer, no major floor drama required, contrary to the horror stories people talk about on PY.

Here's the link to the article in Super chevy: http://www.superchevy.com/how-to/tra...-installation/

[Half-Inch Stud]

Brad, Thanks for the link.
I gots the 2 types of 4L80s readied: the classic cooling lines up front and the relocated cooling line near the planetary (THAT 4L80 probably will have cooling line angst huh).

So, the classic cooling line 4L80 is the 1st choice. Seems odd that the speed sensors on the Driverside case would hit the floorboard...perhaps. Well my floor has the bolt-in 4-Speed sheetmetal hump so there ought be some "Pry & flex" afforded from above...assuming I pull the carpet (not). Well I will if I must.

[Half-Inch Stud]

Perfectly working TH400 being removed.

[Half-Inch Stud]

Originally Posted by Half-Inch Stud

Perfectly working TH400 being removed.

Down n out.

Flex-plate off because 4L80 converters don't seat with the HO bolt plate, so put plate away & shorter flexplate bolts pulled from stash.

Tossed my 2 spare flexplates re-drilled for 4L60 6-Bolt converters. Looks like I will be drilling 3 more hole in a stock flex plate.

Cleanup for dinner out. I'm out.

[Half-Inch Stud]

Two 4L80 types shown, you would want the pair of Cooling lines up front for the A-body GTOs.

mechanical speedos added to the tail cup, and drive gear added to output shaft. you'll want that. 1speedo port covered with aluminum tape to keep dirt out.

[Half-Inch Stud]

Here you can see where the 4L80 case got rat-tailed to provide clearance for a pair of adapter plate bolts. Next post will show those bolts. Got to grind the case to clear those bolts or the case won't seat flush with the Adapt-plate or block...dry-fit everything to avoid trouble.

Here's the 68-PC with Switch Pitch that came out. Working just fine and no leaks ( 4L80 better fit). This 4 L80 project is many years (5?) late on install because I really enjoy the TH400 auto-shift. 4-Speed GTO getting a 4-Speed planetary-base CRUSHER.

Dipstick tubes on display here too. 4L80 is a locking tube, and if it is too long, then it will be easily knocked back to an excellent height.

[Half-Inch Stud]

The adapter plate is bolted in place with the 4 upper bolts. 4L80 shares the Block dowels and lower bolts as BOP & TH400. Adapter plate perimeter trimmed to matched block for goodness sake.

As mentioned in Prior post, the HO plate/collar hits converter so it stays off. Dual-pattern Flexplate is easy to modify the 3 inner hole pattern to grow into the 6-Bolt Converter pattern.

Converter "button" is same as TH400 button at about 2.00"

[Sirrotica]

Good job Mark, you made great progress this weekend and illustrated that a 4L80e swap isn't going to be a major job that seems to scare many people from doing it.

Thanks for the photos, makes all the details easy to comprehend.

One other thing I've been meaning to ask you, isn't Bluebell AL a fictitious place?

[Half-Inch Stud]

Originally Posted by Sirrotica

......One other thing I've been meaning to ask you, isn't Bluebell AL a fictitious place?

Bluebell, AL should exist but it doesn't. Only is some TV series.

As for the swap to OVERDRIVE, thanks for support. This Swap involves designing on the fly, along with pre-planned mods. An original 4-speed
GTO with a column-shift added. I like it, but it sure begs for the Hurst Shifter.

[Baron Von Zeppelin]

Was that the Designing Women show ? BlueBell
or a Skynyrd tune ?

My hometown had a BlueBell outlet store that sold Wrangler Jean items.


Serious question though -
What is nominal torque the 4L80 can handle (non-racing environment but random gearhead "get-down-on-this-mofo")
Like with a healthy D-Port 455/#64 heads 3.31 axle

[Half-Inch Stud]

Originally Posted by Baron Von Zeppelin

Serious question though -
What is nominal torque the 4L80 can handle (non-racing environment but random gearhead "get-down-on-this-mofo") Like with a healthy D-Port 455/#64 heads 3.31 axle

Any non-boosted 455 TQ output is easily handled by the TH400 & More so handled by the 4L80.

4L80 has a larger input shaft dia, but the Mainshaft & planets are....identical.

Heart of Dixie is the only show I know of filmed in Bluebell AL

[Sirrotica]

Originally Posted by Baron Von Zeppelin

Was that the Designing Women show ? BlueBell
or a Skynyrd tune ?

My hometown had a BlueBell outlet store that sold Wrangler Jean items.


Serious question though -
What is nominal torque the 4L80 can handle (non-racing environment but random gearhead "get-down-on-this-mofo")
Like with a healthy D-Port 455/#64 heads 3.31 axle

In stock configuration the 4L80E is rated at 440 lb ft of torque, for anyone that doesn't know, the 4L80E uses 75% of the same internal parts that a T400 uses and has an overdrive unit designed into it by the Hydramatic engineers. It's the Pontiac old reliable T400 with OD.

With a shift improver kit by TransGo, the 4L80E reliability is again improved and without billet parts can sustain easily 650 HP. With a billet input shaft that rating is upped to 750 HP with a transmission that does not need constant attention and freshen ups periodically.

The proponents that advocate to use a T400 with a Gear Vendor unit grafted to it, have it already available in the factory designed Hydramatic 4L80E and in a more compact package too because with OD the 4L80E is only approximately 3 1/2 inches longer, and 57 lbs heavier than a T400 short tail transmission.

The part that seems to have everyone gun shy is that the 4L80E is electronically controlled and either requires a TCM and attendant wiring harness to be used in the fully automatic mode. Or you can opt for no electronics (as Mark has done on his 4L80E) and buy a kit to make the transmission fully manual and it has to be shifted each time you stop to first and brought up through the gears, the same as a 4 speed manual transmission.

Of course using the electronic controls makes the 4L80E very adjustable as far as line pressures, shift points and of course has no TV cable to mess with, and is designed for use behind high torque/HP engines in a format that has been used in the hot rod/ muscle car arena for decades, it's the T400, with factory designed OD.

The 4L80e was designed for GM light trucks and motorhome chassis to 18,000 lbs. with diesel and a minimum 350 CID gas engines. When the need was for higher CAFE averages to meet gov't mandates in early 90s. The 4l80E debuted in 1991 and was used by GM until 2013 (22 years) making the junkyard supply fairly abundant. The 4L80E has an OD unit as well as it is originally equipped with a lockup torque convertor feature that can be used in a HP application, or opting out of the lockup feature.

[Half-Inch Stud]

Torque capability is numerically higher than cited HP.
Line pressure on my 4L80s are controlled by vacuum modulator; installed inside pan!

[Baron Von Zeppelin]

That was a quick sell.

Wonder if a 68 His & Hers shifter / Factory Console could be used/modded with it ?
[full manual mode]

[Half-Inch Stud]

Originally Posted by Baron Von Zeppelin

That was a quick sell.

Wonder if a 68 His & Hers shifter / Factory Console could be used/modded with it ?
[full manual mode]

YES Floor Shifter would be easier because you have the Manual Valve lever by cable. NO Column-Shift needed. Easy-access to switches too.

YES: curved switch is likely useful for something, and other switches can be added for to get 1,2,3,4.

Locking Converter could be anything up to a Clutch pedal (like I have).

[Sirrotica]

Originally Posted by Baron Von Zeppelin

That was a quick sell.

Wonder if a 68 His & Hers shifter / Factory Console could be used/modded with it ?
[full manual mode]

https://shiftworks.com/collections/g...conversion-kit

[Baron Von Zeppelin]

Originally Posted by Half-Inch Stud

Locking Converter could be anything up to a Clutch pedal (like I have).

so, something has to be engaged/triggered/activated while stationary ?
and de-activated to go mobile again ?

Maybe a second "dimmer switch - foot activated"
Its a 70 GTO Auto Console car [adding 68 H&H shifter]
Revvv it up - pop the foot switch and do a wheelie - yeh this might be good.

Originally Posted by Sirrotica

https://shiftworks.com/collections/g...conversion-kit

Wow
Thanks for that link. Perfect !

[Half-Inch Stud]

Originally Posted by Baron Von Zeppelin

so, something has to be engaged/triggered/activated while stationary ?
and de-activated to go mobile again ?

Maybe a second "dimmer switch - foot activated"
Its a 70 GTO Auto Console car [adding 68 H&H shifter]
Revvv it up - pop the foot switch and do a wheelie - yeh this might be good.
..Wow..Thanks for that link. Perfect !

Converter has a clutch, so you can leave it unlocked forever, or switch the solenoid to engage the Lock the converter. Highway cruise or thatStich feel of stalling out when approaching a Stop sign.

I have a switch to engage using the stock clutch Pedal, and include a switch for full time unlock. return spring on Clutch pedal is easy.

[antique69lemans]

I've been gathering parts for the same swap. Where did you get the speedo cup ? I machined one and used large muncie drive gear.. Have you determined driveshaft kength ? Theoretically it will be 3.25" shorter.