A few 727 questions on seal replacement and cleaning

[Dino]

The trans is a 74-75 727 and works great but it has a leak coming from the torque converter area. I pulled the converter and saw traces of fluid around the hub seal. The pump housing also shows traces of fluid and it looks like someone used some blue silicone there. Of course this could be fluid flung around by the converter once it leaked into the bellhousing, but one of these must be busted! So I'd like to replace the seal and the housing gasket so how do I do this? How do I remove the pump housing?

The outside of the trans is pretty grimy and someone has painted it black...yeah.

I'd like to soak it in purple cleaner and power wash it but I'm not sure if that is wise, even if I do seal up the cooler line nipples and such.

The gear selector shaft seal should probably be replaced as well, is that hard to do?

The dipstick seal is hard and doesn't seem to seal all that great anymore so I need that one as well.

Is there a specific brand of seals and gaskets I need to buy or is there a small kit that contains all of these? I have a good pan gasket that is reusable so I don't need that.

[Dino]

more

[crj1968]

I just replaced my dipstick O-ring. I just took the dipstick into auto parts store and found and oring the fit. It worked but I also RTV'd it like a mad man, just cuz I'm not worried about beauty right now.

I then did the selector shaft seal- got those parts on ebay. There are two, one for the shifter and one for the kickdown post.

This is what I bought 

http://www.ebay.com/itm/Dodge-Mopar-727-TF8-Transmission-shifter-Shaft-Shift-Linkage-detent-seal-kit-/260763978475?hash=item3cb6be8aeb:g:ba0AAMXQEgpTDMWM&vxp=mtr

For that I had this "special" tool that is supposed to work from the top - Probably would work that way with tranny out of car- But I ended up dropping the valve body and popping it out from below.

If you wanna try my special tool I can send it to you-

Now my pump housing is leaking like yours   

[Dino]

Oh no! Are you going to take the trans back out?

I found a video where they showed how to remove the pump housing with a slide puller so ?I need to find one of those. I really don't want to mess with the bands or anything.

Funny, I just put the auction for those seals in my watch list this mornin. Thanks for confirming those are the ones I need.   

So what's special about the tool? And thanks for the offer to let me borrow it by the way.   

[crj1968]

Yeah- I'm a little burned out on trans leaks so I'll deal with it later.

I've never dropped a valve body before I did this shaft seal replacement. It really wasn't a big deal- the little shifter detent ball and spring fell out but that was easy enough to get back. But there's no messing with band or anything. Just took it out and put it back in.


BUT if you want to do it from the top you just take off the two levers- this tool goes over the kick down lever and then threads into the larger shifter seal, and then you can pull it out.
The smaller seal around the kick-down is easier its soft and you could just pick it out and put the new one in.

I was actually successful using the special tool on a slant six car with the trans still in car but on my charger with my exhaust pipe in the way etc...no such luck.

I think with your trans out, the tool will work well for you. Be happy to loan it to you. or sell it to you for $1000. that's a deal.  

[Dino]

I'd say that's a steal! 

Thanks but I think I can get it out without the tool, I'll poke a little hole in it, stick a screw in there and pull it up. If all else ails I'll remove the valve body. I may need to do that anyway unless I can get that pump out from the bell housing end.

I found the pump seal kit for $29.

http://www.ebay.com/itm/271479921199?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

The individual seals are much cheaper locally but none have the small washer type seals that go onto the pump bolts so the kit seems to be the only option.

[crj1968]

Sounds good- and good luck!  let me know how that pumps seal goes as I'm next. 

[John_Kunkel]

I found a video where they showed how to remove the pump housing with a slide puller so ?I need to find one of those. I really don't want to mess with the bands or anything.

The recommender procedure for pulling the pump involves tightening the front band to prevent the guts from coming out with the pump. Even then, it's a good idea to push back on the input shaft as the pump is removed. If the pump was installed with RTV, it's likely not gonna come out easy.

You can make a slap hammer using 3/8"-16 all-thread rod and any kind of weights with a 3/8" hole through it. My homemade pullers are on the bottom in the pic below.

[Dino]

Nice! I'll make some homemade pullers then. I'll just have to find something to use as a weight.

Tightening the band is the bolt on the side of the case if I recall. Do I simply turn it a certain amount and when everything is assembled again I loosen it the same amount or is it more involved than that?

[crj1968]

Oh man that sounds like a PITA. 

[John_Kunkel]

The front band adjuster is on the outside just above and forward the shift lever, back off the jam nut and tighten the adjuster just snug to hold the guts in. When finally reassembled, back the adjuster off two turns and tighten the jam nut.

[Dino]

Will do, thanks John!   

I'll get the valve body out as well so I can keep an eye on the guts. With the body out I'll be able to get the shift shaft seal out a whole lot easier as well.

[ACUDANUT]

I wish you luck.  I have yet to own a 727 that does not leak. 

[Dino]

All I can do is try. I ordered a seal and gasket kit and cleaned the housing in preparation. It could stand as coat of paint though. I'll have to see what I have that looks like aluminum.

[crj1968]

you should paint it black.   

[Dino]

you should paint it black.   

[Dino]

I just received the gasket and seal kit. It's part number k22950C if anyone needs one. It seems to have everything I need and then some so I'll replace as much as I can.

Should I also buy the front pump bushing by the way? It's only like $4 at O'Reilly but I don't know if I need any special tools or not or if it's even recommended to replace..

It looks like this kit also came with the steel pump rings. Should I replace these? The trans works fine, it just likes marking its territory.   

[Dino]

I took the pump out today and cleaned off all the silicone. Replaced the gaskets and seals, replaced the shift shaft seal and was about to finish for the day by replacing the tail seal. When I took the front seal out I compared it to both seals that came in the kit. Both had a little lip on them which the old one didn't have, but one of them was the same thickness so I installed it in the pump. I now pulled the tail seal and find it's the same thickness as the one I stuck in the front pump, the one I have left is thicker. See pic. Old v new. When I look up the seal online it seems to be that the thicker one is correct, but it's 0.56" thick to the flange while the housing is only 0.5" deep.

So what happened? Was I supposed to put the thicker one in the pump? Will the one that I put in there be alright and should I just get a new tail seal or am I pulling the pump again?

[John_Kunkel]

Neither one looks correct, the 727 pump seal shouldn't be much thicker than .350" and has an OD of 2.628".

[Dino]

That's interesting. The OD seems correct, at least the old one fits nicely in the housing and it didn't leak, but it's about .42" thick.

You wouldn't happen to have a part number for the correct Napa seal or similar?

[Dino]

I found one locally that is the correct size and has the boot on it. National #7300S

[John_Kunkel]

7300S is a tailhousing seal. I thought you were questioning the pump seal. 

[Dino]

Ah no, bad wording on my part. I didn't even notice you were talking about the pump seal. Sorry about that.

Any way, it turns out I did install the correct pump seal and the thicker seal is in the picture one that is sold at many places as the tail shaft seal, but it's too thick to fit the housing. At least the housing of my '75 trans.

The 7300S seal fits perfectly so all is well. I also changed out the throttle shaft seal today and the dipstick tube seal so the trans is just about done.

Tomorrow I'l install the filter and the pan and then I'll probably shoot a coat of silver on it to make it look a bit nicer.

[crj1968]

Nicely done Dino.

Here's to no leaks !!     

[Dino]

Thanks! Unfortunately I won't know if it leaks or not until it's back on the road, and that's a long ways to go!

[ACUDANUT]

Wanna come do mine ?