Allison at545 missing plug from bell housing?

[NovaTRON]

Have this quick question, I hope someone can answer before I make the move on buying this bus. This is on a 1995 Thomas school bus. The engine is a Cummins 5.9 12 valve and transmission appears to be a Allison at545. My question, in between the engine and trans oil pans is the bell housing (?), I believe, Where you see a hole. It's a threaded hole and a plug appears to be missing. What is that hole? Is it for inspection or is it to hold fluid? I maybe buying this bus TODAY, depending on if this missing plug is a big deal or not. Please help!

[djdalfaro]

Originally Posted by NovaTRON

Have this quick question, I hope someone can answer before I make the move on buying this bus. This is on a 1995 Thomas school bus. The engine is a Cummins 5.9 12 valve and transmission appears to be a Allison at545. My question, in between the engine and trans oil pans is the bell housing (?), I believe, Where you see a hole. It's a threaded hole and a plug appears to be missing. What is that hole? Is it for inspection or is it to hold fluid? I maybe buying this bus TODAY, depending on if this missing plug is a big deal or not. Please help!

It is a hole to access the bolts on the torque converter. No worries.

[NovaTRON]

Originally Posted by djdalfaro

It is a hole to access the bolts on the torque converter. No worries.

That's what I thought, thanks for confirming. I'm riding the train on my way Temecula CA to purchase this bus and drive it 1200 miles back to Seattle.

[Rivetboy]

Originally Posted by NovaTRON

Have this quick question, I hope someone can answer before I make the move on buying this bus. This is on a 1995 Thomas school bus. The engine is a Cummins 5.9 12 valve and transmission appears to be a Allison at545. My question, in between the engine and trans oil pans is the bell housing (?), I believe, Where you see a hole. It's a threaded hole and a plug appears to be missing. What is that hole? Is it for inspection or is it to hold fluid? I maybe buying this bus TODAY, depending on if this missing plug is a big deal or not. Please help!

Like you said, it is a missing plug no big deal. My TC 2000 5.9 /AT 545 was also missing it. The only thing inside the bellhousing is the tourque converter and the ring gear, some would call it the flywheel.There is no lubricants in there. My guess is that it is an inspction port.

[Rivetboy]

Actually, no. The torque converter bolts come out through a small access panel on the drivers side forward of the bellhousing, right by where the hole is the barring tool fits into to rotate the crankshaft by hand.

[NovaTRON]

Originally Posted by Rivetboy

Actually, no. The torque converter bolts come out through a small access panel on the drivers side forward of the bellhousing, right by where the hole is the barring tool fits into to rotate the crankshaft by hand.

So is it an inspection port? Being that it's on the bottom AND threaded made it appear to be a drain plug.

[Rivetboy]

Originally Posted by djdalfaro

It is a hole to access the bolts on the torque converter. No worries.

If you look to the left of the mount, the big hole with light coming through is where you remove the torque converter bolts and the round boss above it is where the barring tool goes. The hole on the side of the bellhosing a few inches higher is where the optical sensor for the tachometer screws in.

[Rivetboy]

Originally Posted by NovaTRON

So is it an inspection port? Being that it's on the bottom AND threaded made it appear to be a drain plug.

Maybe to drain oil from your leaky rear main seal or from your leaky transmission mainshaft seal... but the bellhousing to the block and the transmission to the bellhousing is metal to metal with no seal or gasket.
It is supposed to be dry in there.

[Rivetboy]

Originally Posted by NovaTRON

So is it an inspection port? Being that it's on the bottom AND threaded made it appear to be a drain plug.

Here you go. Actually looking at the bell housing there is an o ring but it seems to supplement the rear main seal to keep oil out of the bellhousing.
Anyhow, good luck

Joe

[NovaTRON]

I got it, thanks for the insight!

[cadillackid]

definitely jyst an inspection hole.. rivetboy has it right.. TC bolts are removed from the "front" side of the flywheel housing.. and you want it Dry inside there.. oil or trans fluid up inside of there is unwanted.



-Christopher

[ol trunt]

Many automatic transmissions have a plug in the torque converter which is accessed through the threaded hole you are asking about. The only thing the missing plug does is to keep stuff (rats, dirt, snow etc.) from entering the area. Though it probably isn't an approved method, wedging a big flat blade screwdriver between the edge of the plug hole and prying against the torque converter is a lazy man's way to rotate the crank shaft. The fact that the plug is missing probably points to a previous tranny service--so not all bad.
Jack

[Tango]

At the risk of sounding cheeky...


Put a cork in it!

[NovaTRON]

Thanks for the insight.
Btw I ended up buying the bus and drove it 1200 miles up to Seattle.
It operated flawlessly. I think i myself a good one

[EastCoastCB]

OP that's a weep hole and when the rear main seal goes it will drip oil out of that hole. 4 of my 5 buses have had leaky rear mains. Its so common that its not necessary to fix it unless its leaking a lot.

[cadillackid]

Originally Posted by EastCoastCB

OP that's a weep hole and when the rear main seal goes it will drip oil out of that hole. 4 of my 5 buses have had leaky rear mains. Its so common that its not necessary to fix it unless its leaking a lot.

on the DT ive found what looks like a rear main may not be at all.. that whole area on my DTA360 was wet outside. and on the bottom insise.. when I drop the trans I decided im going to fix the rear main.. turns out the oil only was a little on the inside and the whole area around the rear main is dry.. the main culprit is the dipstick tube..



but I agree dont plug the hole up...
-Christopher