6L80 4WD to 2WD

[LockDoc]

Originally Posted by First c10

This only applies to the 6L80/90 transmissions. I am not sure if this will fit the 4L transmissions.

The tailshaft housing I used came with the housing, bushing, seal and was even lubed up. I just added the o'ring where the housing attached to the transmission.

OK, thanks.

LockDoc

[First c10]

Originally Posted by Hotrod doddy

Thanks for the info, I should have my tailshaft tomorrow.
Posted via Mobile Device

Hotrod Doddy,
Any updated? How did this work for you???

[Heliarcn]

Great thread here First c10. I have a couple of questions for you.

Any idea what kind of HP this drive shaft would be good for? What would be the limiting factor, or the "weak link" in your opinion?

I realize there is virtually no slip from the transmission output shaft to the center support bearing, but what about the rear portion of the drive shaft? I didn't see any pics of that.

Thanks,
Bret

[brian1971]

subscribed
great thread

[First c10]

Hey Heliarcn, sorry for the late reply as I didn't see it till today....
the truck has probably close to 400 hp now and we haven't had a problem since we did it a few years back. Weak link??? Maybe that it is a 2 piece drive line with a center carrier bearing... probably has 20K miles on it by a young driver 16 now 18 and the 2nd set of tires and "knock on wood" no problems..

Originally Posted by Heliarcn

Great thread here First c10. I have a couple of questions for you.

Any idea what kind of HP this drive shaft would be good for? What would be the limiting factor, or the "weak link" in your opinion?

I realize there is virtually no slip from the transmission output shaft to the center support bearing, but what about the rear portion of the drive shaft? I didn't see any pics of that.

Thanks,
Bret

Thanks Brian

Originally Posted by brian1971

subscribed
great thread

[tk-mpl]

Is the 6L90 trans the same as the 6L80 to swap out the tail housing? I have a 6L90 and I did buy the 2wd tail housing for it, but I was hoping not to tear into the trans to replace to tail shaft. The whole trans has to come apart to replace the tail shaft and there is 2 different ones that it could possibly be.

[Street Smart]

Originally Posted by First c10

I had to put a 2 or 4* shim(cant remember) on the rear axle to lower the pinion angle but other than that it has about 7K miles with no issues. My son drives it everyday.

Did you ever measure all of your drive line angles? Great info btw, thanks.

[First c10]

Originally Posted by Street Smart

Did you ever measure all of your drive line angles? Great info btw, thanks.

Thank you SS

I added a 4* shim to actually rotate the pinion up. Since the truck was lowered



Tk-
I do believe the tailshaft housings are the same but the spline count on the output shaft are different.
6l80 is like a th400. 32 spline and
6l90 is like 29 spline.
But not 100% sure.
If I had to do again I would not have removed the rear seal and pulled the plugs. I would have just lubed up the shaft and spline as it doesn't move.
But other than that it runs fine.

[tk-mpl]

Well I will definitely need a slip yoke as I am running air ride. The camaro shaft looks like it would work but probably a little over my budget. Stuff like like is hard to find in canada and if you do find it they want an arm and a leg for it.

[First c10]

This is a two piece drive line. If you plan to use a 1 piece drive line it may not work as you only have about 3" of spline in the 4wd trans tailshaft the reason mine does not slip is because the front drive line has a carrier bearing that does not move in and out. It's the rear driveline that moves in the spline of the front driveline. Check out the pictures earlier in the thread.

[tk-mpl]

Mine is a one piece shaft. The truck is a shortbox stepside.

[FAKKY]

So bumping this for info.
Im following but also a little confused.

Basically looking a dropouts for my 57 panel (2WD) with 4WD trans (4l60/4l65e/4l80e/6l80e) as there are many more options and easier to find as they were more common.

I read on some threads and some guys talk about switching out tail housing from a 4WD with a 2WD. But from what I can tell ..... seems like ALL of these transmissions requires that the output shaft be removed (shorter 4wd) to a longer 2WD. Basically a full tear down. So this is false ?

Are there any ways to bypass a full rebuild on any trans -- this seems like one way ... but requires a 2 piece drive shaft.
Since I dont have a drive shaft and likely will have to get one made ...... could this be an option ?

I saw someone mention a drive shaft with the slip "built in". IS this another option ?

thx

[First c10]

Hello Fakky,
Ok I cannot confirm but the 4L series transmissions will need to have the tail shaft and tail shaft housing replaced.

On the 6L series 4wd you will need a 2 piece driveshaft unless you change out the tail shaft to a 2wd. As the 4wd does not have much spline to move in and out.

If you want to use a 1 piece drive shaft with a slip built in the driveline you will have to figure out how to attached the yoke to the transmission. Like have the 4wd tail shaft drilled and tapped to accept a bolt to secure the yoke to the trans.

Not sure your suspension set up but if the truck is lowered maybe the overall travel (compressed to full rise) will not cause the drive line to move much in and out to cause a problem.
The 2 piece drive line uses the carrier bearing mounted rigid so it does not travel in and out at the trans.

Hope this helps.
Scott

Originally Posted by FAKKY

So bumping this for info.
Im following but also a little confused.

Basically looking a dropouts for my 57 panel (2WD) with 4WD trans (4l60/4l65e/4l80e/6l80e) as there are many more options and easier to find as they were more common.

I read on some threads and some guys talk about switching out tail housing from a 4WD with a 2WD. But from what I can tell ..... seems like ALL of these transmissions requires that the output shaft be removed (shorter 4wd) to a longer 2WD. Basically a full tear down. So this is false ?

Are there any ways to bypass a full rebuild on any trans -- this seems like one way ... but requires a 2 piece drive shaft.
Since I dont have a drive shaft and likely will have to get one made ...... could this be an option ?

I saw someone mention a drive shaft with the slip "built in". IS this another option ?

thx

[FAKKY]

Originally Posted by First c10

Hello Fakky,
Ok I cannot confirm but the 4L series transmissions will need to have the tail shaft and tail shaft housing replaced.

Seems like the output shaft is held in place with a snap ring/gear assembly .....1st thing to go into trans .... so requires full teardown to get to.

Most guys talk about swapping tailhousings ...... but thats seems more to me for the VSS and physically housing the longer shaft once you remove the Transfer case adapter. But you still need to tear into. ??

Originally Posted by First c10

On the 6L series 4wd you will need a 2 piece driveshaft unless you change out the tail shaft to a 2wd. As the 4wd does not have much spline to move in and out.

If you want to use a 1 piece drive shaft with a slip built in the driveline you will have to figure out how to attached the yoke to the transmission. Like have the 4wd tail shaft drilled and tapped to accept a bolt to secure the yoke to the trans.

Not sure your suspension set up but if the truck is lowered maybe the overall travel (compressed to full rise) will not cause the drive line to move much in and out to cause a problem.
The 2 piece drive line uses the carrier bearing mounted rigid so it does not travel in and out at the trans.

Hope this helps.
Scott

Its a stock suspension right now ...... different rear end (8.8 exploder) but dont expect much travel.

Im not really worried about a 1 or 2 piece driveshaft. As either way the chances are its going to be custom due to 57 truck with 8.8 explorer rear axle - guessing not many drivelshafts will bolt straight up.

So - on the 6l80e .....

1) Is there no VSS on the outputshaft/tailhousing ? So not a concern like the 4lxx series ?

2) Do all 4lxx series have VSS on the output shaft - looks like maybe the 4l60 doesnt but the 4l80 does ........ but still ..... seems both need full dissasembly.

3) MY truck had a single driveshaft. I assume I can convert to a 2 piece custom driveshaft with carrier bearing - just need a way to mount the carrier bearing. If I went this way then technically could follow the same modications you came up with here ?


Seems a little confusing on which trans require exactly what modifications to convert to 2WD from 4wd. But from about 6 hours of research this is where I am at currently.

thanks !!

[FAKKY]

--- update

=====4lxx series

So did more research. Pretty sure on the 4l60e =>4l80e you cant just swap out tailhousings. You do effectively do a tailhousing swap .... but it requires replacement of the output shaft to a longer output ... and that is held inside the transmisison as an essaembly with a snap ring. The kit would like like this ....

https://www.ebay.com/itm/261775210599?ul_noapp=true


But required outputshaft replace so have to get inside.


On the 6l80e series I havent looked yet ..... assume its similar.
So this idea is still intriguing to prevent that. BUt ...

How do you add a custom 2 piece driveshaft to the trucks. do you just fabricate a carrier bearing "holder" and thats about it - or more to it. Im thinking ots probaby not worth it - makes sense on original C10 when re-using 2 piece shaft as the costs would be

$40-$80 for 4l80e yolk
$80-$120 for rear short tailhouse
$custom driveshaft and fabrication of carrier support
etc

So -- not as bad as rebuild but for the effort and the non-standard appracoh in other trucks without a stock 2 piece DS ..... think Ill probably keep hunting for a 2WD.