My 4L60e to 4L80e Swap Journal:

[randeez]

Did you get the one you posted above?
First make sure the trans has the bosses threaded for it.
They're probably m6x1.0 all they have to hold is the bracket 15mm-20mm in length should be plenty.

 

[srs5150]

I did get the one above.

M6x1.0 just falls in
M7x1.0 seems to fit but bottoms out after 2 turns
M8x1.25 seems to fit but botoms out after 2 turns
No SAE came close.

Tried every singe one of these with no luck.

 

[Rocket Man]

I did get the one above.

M6x1.0 just falls in
M7x1.0 seems to fit but bottoms out after 2 turns
M8x1.25 seems to fit but botoms out after 2 turns
No SAE came close.

Tried every singe one of these with no luck.

View attachment 236884

Tap it yourself. Then you’ll know what it is. Make it the next size up in metric or try a M8 tap. If it doesn’t work you can drill it bigger and go with the next size up but only drill to the bottom of the original hole, be careful to not drill through duh.

 

[wjburken]

I did get the one above.

M6x1.0 just falls in
M7x1.0 seems to fit but bottoms out after 2 turns
M8x1.25 seems to fit but botoms out after 2 turns
No SAE came close.

Tried every singe one of these with no luck.

View attachment 236884

There are fine thread and coarse thread metric. In metric the second number is the distance between threads, not the number of threads per inch like SAE.

M7x1.0 and M7x0.75
M8x1.25, M8x1.0 & M8x0.75

My guess would be, based on what you are describing, is you need an M8x1.0 bolt.
If it was an M7 hole you would not likely even get 2 turns out of an M8 bolt.

 

[srs5150]

So I took my skirt off, quit cryin' and ran a M8x1.25 tap into the holes and got the M8x1.25 bolts to work. The rest of the day went amazingly well:


Bracket:


Trans oil lines


Starter:



Front Drive Shaft / Headers / Bell Housing Bottom Cover:



Rear Driveshaft:




I think I can finally see light at the end of the tunnel. Still gotta run the speed sensor up to the ECM and wire it in and do a segment swap from a 4L80e vehicle but I'm encouraged by today. Gotta go to the in-laws for the weekend so it won't be very productive car wise, but I hope to make more progress next week. Thank you to those who chimed in and offered a helping hand.

More to come......

 

[srs5150]

Well, .... I had everything on and filled it with ATF. Instead of turning the key and celebrating a running truck, I was greeted with this:





Should I drain it, take the pan off, replace the gasket and reassemble, or is there an easier fix?

 

[ivin74]

Try tighten up the bolts but i would drain an replace the gasket.

 

[Rocket Man]

Well, .... I had everything on and filled it with ATF. Instead of turning the key and celebrating a running truck, I was greeted with this:

View attachment 237204

View attachment 237205

Should I drain it, take the pan off, replace the gasket and reassemble, or is there an easier fix?

I’ve had a leak both times I replaced my trans, and both times I torqued the pan bolts to spec and it resolved the issue. Then after a couple hundred miles, I checked torque again. Make sure to torque them to spec, don’t overtighten them or you’ll bend the pan flange. If that doesn’t fix it, then you know what you have to do.

 

[89Suburban]

Great work here man.

 

[srs5150]

I tried torquing to spec. Still leaked.
Tried loosening them some, still leaked.
Tried torquing to speck, still leaked.
Tightened a little more, still leaked.

Then I called the company that I bought the 4L80e from - without hesitation, they are sending me another pan and gasket no questions asked. On hold for a few more days.

I was SO close to turning the key today, I could taste it. Oh well, what's a few more days. I keep reminding myself that I have a beater to drive while the truck is down, so I shouldn't try to hurry it.