Help with holes in back of 4l80e (1 Viewer)

[workingdog]

I'm transitioning the 4l80 in my '66 fj40 from 2 piece Advance Adapters adapter and toyota transfer case to one piece adapter and Atlas 2. I put it all together and had a leak from the adapter. When I took it all back apart, I took pictures down to my transmission guy and he said that both of the holes top and bottom need plugs.

I don't know how it worked in the old set up, unless the adapter was just wet and was sealed better. The new adapter is metal on metal at the transfer case connection and it leaks out there. It's so rare to need these plugs, that my transmission guy doesn't have any, they are not in the rebuild kit, the ones he had were a little big.

Any idea? Source for plug, something else I can use. There's no pressure back there, just flow. This is one of the last issues to get this beauty back on the road. And I really don't to take it apart again. (lower links, skid plate support structure, rear driveshaft, transfer case, yada, yada, yada).

 

[GLTHFJ60]

Tap for npt and throw some brass plugs in there?

 

[EWheeler]

Hey @workingdog . I have no first hand experience, but quick google search of "4l80e rear plug" came up with a couple hits that points to there being a "rear lube orifice hole" that allows oil to lubricate the output yoke in a 2wd application, or maybe some kind of bushing, or both. I found a thread that lists part number for plugs, one for 2wd and one for 4wd. I'll let you do some more research to determine if this is what you're after.

AWD 4l80e to 2wd - LS1TECH - Camaro and Firebird Forum Discussion

Automatic Transmission - AWD 4l80e to 2wd - have 2 AWD trans, vehicle that its going into is 2wd already. so swapping from AWD to 2WD needed parts... rear planetary with reluctor 2WD output shaft 2WD tail shaft housing anything im missing? don't waste time giving me the lecture about selling...

ls1tech.com

 

[workingdog]

@EWheeler - YOU ARE THE MAN (or whatever way you choose to identify).

 

[EWheeler]

@workingdog

Ok, so after reading some more, it sounds like the plug goes into the hole at the 3:00 orientation. I don't know what those 12:00 and 6:00 holes are for. Looks like you need to check and make sure there isn't a weep hole in the 3:00 hole. Here are two different plugs for that hole from my google search:

4L80E LUBE ORIFICE BLOCK REAR OUTPUT YOLK 4WD TRANSMISSION CHEVY 4L85E MT1 MN8 | eBay

Can be used on ALL YEARS (1991-UP) 4L80E, 4L85E, MT1, and MN8. end_elivehelp_btncode Rear Case to Extension Housing Orifice Block, used on 4WD 4L80E. Orifice Block (4WD).

www.ebay.com

4L80E LUBE ORIFICE CASE PLUG REAR OUTPUT YOLK 2WD TRANSMISSION CHEVY GM 4L85E | eBay

REAR CASE LUBE ORFICE FOR 2WD 4L80E / 4L85E TRANSMISSIONS. YOU NEED THIS IF YOU REMOVED YOURS FOR CLEANING OR ARE CONVERTING TO 2WD.

www.ebay.com

see the little weep hole in the middle of the 2wd plug?

 

[EWheeler]

Hey @workingdog . I have no first hand experience, but quick google search of "4l80e rear plug" came up with a couple hits that points to these being the "rear lube orifice holes" that allow oil to lubricate the output yoke in a 2wd application. I found a thread that lists part number for plugs, one for 2wd and one for 4wd. I'll let you do some more research to determine if this is what you're after.

AWD 4l80e to 2wd - LS1TECH - Camaro and Firebird Forum Discussion

Automatic Transmission - AWD 4l80e to 2wd - have 2 AWD trans, vehicle that its going into is 2wd already. so swapping from AWD to 2WD needed parts... rear planetary with reluctor 2WD output shaft 2WD tail shaft housing anything im missing? don't waste time giving me the lecture about selling...

ls1tech.com

@workingdog Read posts #15 & 20.

 

[EWheeler]

4L80E 4WD Lube Plug - ACDelco 9427692 - WARR Performance LLC

This plug is installed in the rear case lube hole when used in a 4 wheel drive application. These ship free anywhere in the US! p/n 9427692

warrperformance.com

 

[workingdog]

Okay, it's clear as mud. I ordered the part mentioned in the ls1tech posting. Have I ordered the wrong part. Is the part at WARR performance different? The same.

There is no hole in the 3 o'clock plug.

I could just tap and brass plug it.

 

[EWheeler]

Okay, it's clear as mud. I ordered the part mentioned in the ls1tech posting. Have I ordered the wrong part. Is the part at WARR performance different? The same.

There is no hole in the 3 o'clock plug.

I could just tap and brass plug it.

You needed to read the thread and make an educated decision, i didnt provide a solution, just a possible path to one. If there is a plug in the 3:00 hole in your trans, and there is no weep hole in it, then the source of your fluid may be elsewhere and the information i provided may have only eliminated one possible source.

 

[workingdog]

So, I called back Advance Adapters again today, and when they gave me the same stock answer he called someone and he's what he said. The 4 wheel drive version had soft plugs in those holes - which are impossible to find. So, if you don't have them, you RTV the surfaces between the adapter and the transfer case and just let it be wet in there. I'll have to top up the trans once it sloshes some in there, but that's okay.

Disappointed that AA didn't understand this. Would have been so easy to put it together right the first time.

I'm tempted to thread and plug the two holes since I have the thing open.

 

[workingdog]

Okay, WFO sent me to JR transmissions in Auburn (who supplied it initially) and they said the soft plugs can not be gotten and to tap and plug. Apparently it's pretty common on the 6l80e, but not that common on the 4l80e.

 

[matzell]

Factory from GM would have an o-ring on the trans to adapter and a paper gasket on the t-case side...I pulled a t-case off a 99 silverado 4l60 yesterday and it leaked atf out from trans. As long as it is sealed it should be good.

 

[workingdog]

@matzell - thanks for the information, that's helpful. Plugs are in, I'm waiting for the lock tight to setup to make sure it's good, then I'm going to put it back together with RTV between the adapter and the transfer case. really don't want to have to take it apart again.

 

[peesalot]

Contact Georg at Cruiser Brothers, he knows auto's,