rear main seal and transmission front seal

welcomehome · 01-17-2017, 10:59 PM

2000 international 3800 t444e bluebird with at545 transmission, midsize handy bus with wheelchair lift.

so i am in the process of replacing my flexplate that has a lot of bad teeth.
upon suggestion from another forum member from another thread i want to also, while ive got the tranny separate from the engine, replace the rear main seal and transmission front seal as well.
so far ive only just got the driveshaft off but its getting about time to order parts. does anybody have advice on changing these seals? part numbers also could be helpful if anybody knew them so i may research them before going to the store to order.
thank you all so much for your advice.

superdave · 01-18-2017, 06:41 AM

Allison AT545 AT540 Transmission Gasket and Seal Rebuild Kit 1970 and Up | eBay
her ya go and you can replace the rear, pan and fill tub also

welcomehome · 01-18-2017, 11:49 PM

thank you. that gives me a better direction to go on.
i was searching for an allison at545 manual or pdf but had no luck on the allison site searching or the net in general. i think im gonna go to the local international shop who says they have a flywheel kit for me and see how much they would charge me for a "rear main seal" and a "transmission front seal" if ordered individually.
anybody got any tips on changing the transmission front seal? is it just behind my torque converter? thank u

cadillackid · 01-19-2017, 05:56 AM

I dont know the 545 specifically but when ive replaced the front seal on the hotrod GM transmissions ive worked on, the seal was pressed into the pump cover on the transmission.. in my case I had the transmission in pieces to build it up so the front pump cover was off the transmission and on a bench.. I have a seal installer tool as getting them in slightly bent or crooked and they will leak.. I dont know if the seal installer tool for a standard GM will work on a 545 or not.. autozone / o reilly may have the rent-a-tool for the seal installer which would be the route id go and see if it fits..

-Christopher

welcomehome · 01-19-2017, 02:36 PM

i may just do the flywheel change and let it continue to leak if i cant get definitive instructions on changing those seals out. im concerned ill make a bigger mess if i try to change those seals without knowing exactly what im doing. however i imagine it may be as simple as the wheel bearing seals i used to change on my old vanagon.
i think i shall check autozone/ oreilley or other flaps for that tool.
i wonder if u know the torque lbs of any of the bolts involved in this flywheel change. i have the t444e pdf but i dont have an allison manual or pdf that would show these torque values. im having to research and buy a torque wrench. i suppose i could write down all the values of torque as i loosen the bolts but that seems like the jimmy-rigged way of going about it.

Rameses · 01-19-2017, 03:39 PM

Quote:

Originally Posted by welcomehome

i may just do the flywheel change and let it continue to leak if i cant get definitive instructions on changing those seals out. im concerned ill make a bigger mess if i try to change those seals without knowing exactly what im doing. however i imagine it may be as simple as the wheel bearing seals i used to change on my old vanagon.
i think i shall check autozone/ oreilley or other flaps for that tool.
i wonder if u know the torque lbs of any of the bolts involved in this flywheel change. i have the t444e pdf but i dont have an allison manual or pdf that would show these torque values. im having to research and buy a torque wrench. i suppose i could write down all the values of torque as i loosen the bolts but that seems like the jimmy-rigged way of going about it.

Using a torque wrench to break loose a nut or bolt is a really good way to ruin a torque wrench. Plus, it won't give you anything close to an accurate reading on what the torque is supposed to be.

Personally, I wouldn't worry about a torque spec on them anyway. Just put loctite on them and get them good and tight without breaking or stripping anything. The only things in an engine I really worry about getting proper torque on are rod and main caps, and head bolts.

welcomehome · 01-19-2017, 03:44 PM

ok. thank you for that. i will not use the torque wrench for loosening then.

Jolly Roger · 01-19-2017, 06:45 PM

Don't worry about the perfect tool to seat a tranny seal. While you have the seal I your hand you can find a piece of pipe (and yes PVC can work) that fits your seal for driving it in plus include enough to pipe length to keep you away from the shaft.
If it's tight quarters it can still be done.
Use a hammer that fits in your space?
Sometimes it is 3/8" ratchet as a hammer and an old socket in a pair of vise grips to get the job done? That's a different on the side of the road storie?
Front pump seal is nothing to replace if/when you can get to it .
Rear main is a different story depending on your engine/motor and your capabilities.
the rear main an be changed without removing the tranny. They are two seperate animals. And the rear main work wise has nothing to do with the flywheel/flex plate which only provide you access to the tranny front and back. The rear main seal requires seperate attention ?
They are two seperate items and are sealed from each other therefore you can deal with one without effecting the other.
Sorry if I sounded rood it's been that kinda day at work?

bluebird90 · 01-19-2017, 08:56 PM

To change the rear main seal on a 444e, you must remove trans, and flywheel. They are whats called a full circle seal. While it can be done with basic tools there is a trick to getting it in right. Get the kit that comes with the plastic installer if you can.
Jolly roger is thinking of the old school split seals where you have to remove the oil pan and rear main bearing.

bluebird90 · 01-19-2017, 08:58 PM

And yes it is a good idea to change both at the same time. No use having to pull the trans twice.

superdave · 01-20-2017, 06:41 AM

Quote:

Originally Posted by bluebird90

And yes it is a good idea to change both at the same time. No use having to pull the trans twice.

just got my f150 back from the shop. figured it was the front seal on the tranny, nope nope nope. when they put it back together they put it in gear and it started dumping fluid again. turns out after 291000 miles the torque converter developed a hairline crack in a weld. I m o check everything twice and change every seal or gasket you can. and put a new Bendix on that starter also.

cadillackid · 01-20-2017, 07:21 AM

I once hads a converter crack on a GMC... I had a fluid leak and a really wierd sound too... the sound acted like a cracked flexplate.. so I assumed i cracked the flexplate and the converter wobbled to ruin the trans seal.. took it apart, poured the fluid out of the converter and fillled it with kerosene to sit overnight and then id flush it out... left it overnight..

got up the next morning and the garage floor was covered in Kerosene ..

flexplate was fine.. used it as an opportunity to Upgrade to a nice 3000 stall converter..

-Christopher

welcomehome · 02-02-2017, 12:37 AM

so now im looking to install this rear main seal. i see that there is an inner metal ring that has slid out the center of it. i carefully put the metal ring back into the middle of the seal but i wonder if its defective? all the pics online of my seal shows it as 1 piece.?

superdave · 02-02-2017, 06:01 AM

yes a metal ring, spring keeps a little pressure on the seal against the crank, replace that seal. not worth gambling on.

bluebird90 · 02-02-2017, 06:46 PM

No, it's not defective. Look on the end of the crank , do you see a ring or sleeve attached to the sealing area of the crank? Most engines came from the factory with this replaceable sleeve.
If so, and the sleeve is not grooved, you may be able to use just the seal. If there is no sleeve then you may need to install the new sleeve . This sleeve is actually called a speedy or repair sleeve. The new seal should have come with instructions, read them. .You get the old sleeve out by carefully going around the surface of the sleeve with a punch or chisel. this spreads the sleeve so it can be pried off. BE CAREFUL NOT TO DAMAGE THE CRANK SURFACE. Drive on the new sleeve with an appropriate driver

welcomehome · 02-02-2017, 10:06 PM

ok, so i took the seal in to the international dealership and they verified that the seal is fine and by looking at another one they had in stock i saw how the metal ring sits in the seal.
unfortunately the new seal didnt come with instructions.
i rented the installer tool from them for the weekend.
i took off the five 8mm bolts on the rear main seal. i used a hammer to gently tap on a razor blade utility knife between the flanges of the seal and where the old sealant was. with slight prying on the blade the seal came loose and i backed it off the engine.
to my surprise, i looked at the seal and found that there was no metal ring, aka wear guard. now i know it is called a speedy sleeve. im confused as to why my new seal has this metal part that the old seal didnt have installed. can someone please explain this?
also, what kind of loctite do u all use on the metal ring?

thank you.

bluebird90 · 02-02-2017, 11:17 PM

First off, compare the O D of the sleeve to the crank. If they are the same diameter, you dont use the sleeve. If the sleeve O D is larger then you must use it.
Many replacement seals come with the sleeve and must be installed on the crank. If you use the seal without the sleeve it will not seal.

welcomehome · 02-06-2017, 05:35 PM

international cut me a deal on renting the install tool and the rear front seal went in fairly simply.
so now im debating whether or not to replace this at545 transmission front seal. its right behind the torque converter, right? im leaning torwards leaving it alone, since its not leaking. but as others have pointed out: it'll never be this easy to replace that seal again since the tranny is already separate from the engine. but im not finding any detailed guides or howto vids online of replacing this seal and every link i click on for an allison at545 manual seems to just be spam.
does anyone here have experience changing this seal on an at545? how do i get to that seal? is it a common wear kind of seal or might it never leak if i dont mess with it?

Booyah45828 · 02-07-2017, 09:02 AM

Its just like any other input shaft seal. Remove the converter, pull the old one out, and replace. I've never personally had just a seal go bad, usually the bushing wears which causes the seal to wear. It won't hurt anything to inspect it, just make sure the converter is seated properly when you reinstall it. Follow the video I posted in your other thread about this topic and it should be pretty straight forward.

welcomehome · 02-28-2017, 10:47 AM

well i decided not to change the seal on the tranny after taking the torque converter off and finding no signs of leakage. i watched the video, and a bunch of other videos, and decided if it dont need fixin, then dont broke it!
i was very careful to check, check, check, check, and recheck that i rotated the torque converter enough to be sure it was seated properly on the inner set of splines. i could see how someone could easily push it on and get it rotating on the outer set of splines and think it was on there; only to damage their tranny pump when they finally fire it up.
with the tool rented from international the rear main seal went fairly smoothly and seems to be not leaking.
thank you all so much for your help

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