727 rebuild guide....

[thrashingcows]

The torque converter in the 727 in the wagon was starting to lock up at idle, so there was a little work needed for the tranny as well I bet. I have no idea how old the tranny is, but I assume it's all original 1971. So since the tranny would have to come out for a new torque converter, I figured I better get the tranny redone. Well I priced out a few "rebuilds" locally and was not happy about the prices they were charging, so I figured I would just do it myself.

Now I have never rebuilt an automatic tranny, but I have done A833's, and a NV4500, NP205 transfer case, as well as rebuild 12V cummins diesel injection pumps etc. So I figured how hard could it possibly be.

I watched a few Youtube vids on tearing down 727's and rebuilding them, as well as reading through the FSM, and it did not look like I should have any difficulties. In fact I think the NV4500 I converted from 2wd to 4wd and rebuilt, was tougher then this job will be.

So I will document the rebuild process as I go. Not in every detail...you can get the specifics from the FSM or a Youtube vid, but a general "what to expect" if you are doing it yourself.

Took about 2 hours the other day to pull the tranny out of the wagon. I began the tear down yesterday.

 

[thrashingcows]

I knew the clutch material was starting to let go. Every time I serviced the tranny I found flakes of material in the filter, and in the bottom of the pan.





Then the tailshaft has to come off. I had previously done the tailshaft bushing, so this was simple and easy. Will probably just clean and re-install.



Then the valve body has to come out. Just make sure you remove all your shift linkage first. ;)

 

[thrashingcows]

Next you have to pull the main pump out of the front of the case. You need a slide hammer to help it out. I have a big slide hammer a neighbour who is a CNC machine operator built for a single job he did, and never used it after so he gave it to me. But it did not have the proper threaded end to screw into the pump housing. There are two threaded holes just for this, at about 3 and 9 O-clock.

SO I dug through my buckets of misc bolts and found a couple that would work, then welded them together...worked like a charm!





And the front pump out, and the forward and rear drum assemblies.

 

[thrashingcows]

Then once the forward drums were out of the way, you can now pull the sun shell and the main shaft out.



Only thing I did not expect, and of course the parts don't come in the rebuild kit I opted for, was one of the brass thrust washers on the forward planetary assembly was worn out. SO ordered those last night, and will have to wait a few days for them to arrive.



All apart and ready for the cleaning, and rebuild to begin.

 

[72Fury]

A little off track, but is that a hp transmission? The planetary has 4 gears, instead of three.

 

[thrashingcows]

A little off track, but is that a hp transmission? The planetary has 4 gears, instead of three.

Yeah I noticed that as well. Nope it's the number matching tranny to the 71 440 I pulled out a 71 300 4dr parts car that donated it's drivetrain to get the wagon back on the road.

Maybe they were out 3 gear planetaries on that day, so all trannies got build with 4 gear units. ;)

 

[commando1]

A 3 speed and Im lost already. Who the hell is going to be around to rebuild the new 9 speeds....

 

[thrashingcows]

A 3 speed and Im lost already. Who the hell is going to be around to rebuild the new 9 speeds....

Why would you? The rebuild would probably cost more then a brand new unit, or perhaps more then a new car. ;)

 

[commando1]

Cars are becoming Bic Lighters.
Even if it craps the bed after a half dozen lights, you buy a new one.

 

[1970cat]

i'm surprised the kit didn't come with thrust washers. did it come with the plates and discs or just discs?

 

[tbm3fan]

Too bad there is no DVD on this. For me, there was a Ford mechanic, who filmed the rebuild of both the C4 and C6 transmissions. Have both and with them one would have no problems.

 

[1978 NYB]

Just the satisfaction of doing it myself is worth it to me....

 

[Wollfen]

i'm surprised the kit didn't come with thrust washers. did it come with the plates and discs or just discs?

You can buy kits of varying completeness depending on what you need. I always buy the deluxe royal top of the range complete kit every time.

 

[thrashingcows]

i'm surprised the kit didn't come with thrust washers. did it come with the plates and discs or just discs?

Came with all the seals, metal and rubber, new steels, and fibers, front and rear bushings, and all the O-rings and gaskets. All the kits I looked at didn't have the thrust washers. If that one had not worn, the rest would have been fine to re-install.

 

[70bigblockdodge]

Good job, I was trying to document when I did the trans in my Barracuda but stopped remembering to take pictures. Only thing I might add is if your are pulling the valve body anyway you can just knock the pump out from the inside above the front band saves having to have a special tool. 4 pinion planetaries come in everything heavy duty RV 3/4 ton and up trucks any 440 before cast cranks started showing up, /6, 273, 318 in trucks probably will not have 4 pinion.

Which front band do you have the big thick iron one or a flex band.

Thrust washers don't come in the kits because depending on the planetaries they are different.

 

[Samplingman]

Great work I'll be following along, but those pics scare the crap out of me!

 

[thrashingcows]

I could not find a kit with the big heavy duty rigid band. So I have the flex band, is there an issue with these? The rear band I got a HD Raybestos rigid unit though, I had to buy it separately.

I tried prying between the front and rear sections...to get the pump to pop out, but it wouldn't move. It was really easy to make the adapter for the slide hammer, and that hammer is so heavy it took two knocks on each location and it was out.

Turns out I have a 3 gear, and a 4 gear planetary. The 4 gear is on the forward drum, the 3 rear is on the rear drum.

 

[thrashingcows]

Great work I'll be following along, but those pics scare the crap out of me!

Compared to my NV4500 5speed I redid...this thing is a piece of cake! Glad I sucked it up and just got in there, will save myself at least $600 doing it myself. And in my books that is darn good incentive. ;)

 

[70bigblockdodge]

No the rigid band has to be rebuilt, N/A new, they are the reason for the 5.0:1 kickdown lever that is not needed with flex band. My Challenger has a mix and match 4/3 pinions and it is only a 383 HP I guess that was the go between match up lol. Keep it up I'm sure a lot of people will learn a 727/904 not too hard to rebuild. The new 8&9 speeds I would still try it and when I can get it back together take it to the trans guy down the street and he would probably make me promise not to do that again lol

 

[commando1]

Would it really kill them to include a thrust washer assortment for fifty cents more? Seriously....