Please be sure to check the freeze plugs at the back of each cylinder head. They can possibly rot out and leak down onto the transmission. You can use an inspection mirror and a flashlight to check back there for possible leaks, as coolant has a tendency to start at one place and run all over.

 

You don't actually need the trans out from under the truck, just down and back, so it's out of the way. You can do it on the floor.... if you are mobile enough. I know I sure couldn't.

 

Oh, not having to remove the trans would be big.
Also, let's say i decide to do them all! And i got the tranny pushed aside. Can i do the head plugs from underneath?

 

Probably..... May have to tilt the engine back some to get good access, just watch the distributor. Don't beat it against the firewall.

 

Allright. And any idea if the flex plate needs to come off of the crank?

 

Yep, you will need to remove it for better access to the plugs on the back of the block. It's just a bunch of bolts though, comes off easy.

 

Is your truck 2WD or 4WD? If it's 2WD, the removal of the transmission to access the back of the block is much easier to do than if you're dealing with 4WD.

 

I have used "Barr's Leak" for emergency repair of a leaking expansion plug. (Freeze plugs are a misnomer.) It will stop the leak, BUT, it can also stop up your heater core or radiator. Alum-a-seal might slow it enough to get you home.

Personally, I'd pull the engine, especially if it's 4X4. If one is leaking, I will bet you dollars to donuts there are others getting pretty thin. Lack of coolant maintenance is what causes this. The last time I replaced some, one was leaking but three others a screwdriver poked through with minimal pressure. If you replace them all, get the garden hose out and flush the block with water. You'll be amazed at how much rust and sand comes out.

If the engine has a lot of miles on it, this would also be a good time to slap a timing set into it and possibly a high volume oil pump. Not high pressure. Do all that and the engine will really perk up when you're done. Regardless of if you pull the engine or just move the transmission back, replace the front seal on the transmission. If it leaks later, it's several hours of aggravation for a $20-30 part.

If you do put Barr's Leak in it, drain and flush once you get the new lug in. If it doesn't plug your heater core at first, this will keep it from doing it later.

 

NO! DON'T USE ANY TYPE OF STOP LEAK UNLESS YOU WANT TO REPLACE YOUR HEATER CORE/RADIATOR! Mythbusters put a couple of eggs in a cooling system to see if it worked and it did. I wonder for how long though i think they ran it for like a half hour.