Found my tranny leak - 727

[grdprx]

It's on the back, below the output shaft.  Although, I havn't a clue on how to fix it or what it is...   

I looked around via "search"  Looks like the back half may have to be pullled?

[RD]

that is the rear band lever support shaft.  it will have either one or two o-rings that mount to machined grooves in the shaft to seal that area.  most cases the o-ring becomes hard and fluid starts to leak.

now, you replace it by:

1 dropping trans pan
2 dropping valve body
3 remove tailshaft housing
4 loosen rear band adjusting screw and removing rear band strut
5 push shaft out just a smidgeon to see the o ring grooves (easier if you do it some way, not all the way as the rear band mechanism is a three piece system in which all 3 pieces ride on the shaft)
6 put on new o ring(s) and lube with vaseline or trans break in lube
7 clean area on outside of housing with cloth and push shaft back into place
8 apply RTV in that area and smooth around to cover entire shaft
9 reinstall rear band strut and torque down your rear band to 72" lbs and back off 2 and 1/4 turns, then tighten with 11/16" socket (it is supposed to be 2 turns, but when you torque down the retaining nut the retaining bolt will move about 1/4 turn so it comes out to 2 turns backed off total)
10 reinstall valve body and output shaft housing (may be a good idea to get a new rear shaft to main housing gasket at this time...dont need to, but why not?)
11 reinstall trans pan
12 let RTV set for a minimum of 12 hours before you run your car

[69rtse4spd]

Great info., thanks. .

[grdprx]

Ah, thanks RD!   

I haven't actually gotten to drive it yet.  Just broke in the engine last Friday.  I had to replace the reverse band last year in this project...  Atleast I have a little experiance now.   

[grdprx]

One other question, does the transmission need to be removed from the car?  I'm sure it would make the job easier; but I had a heck of a time getting it to mate up with the TQ converter and everything the first time.     I hate waiting to get someone to come around and help....   Hell, I've been waiting a week for assistance with something else, as it is!

[John_Kunkel]

A lot of people fix that leak without any disassembly, just thoroughly clean the area around the end of the shaft (brake clean, then compressed air) and apply a generous layer of RTV over it.

The trick to doing this is to drain the fluid level well below the bottom of the shaft, if you don't do this the fluid will continue to leak around the shaft and prevent the RTV from adhering. Allow the RTV to set before refilling with fluid.

[grdprx]

A lot of people fix that leak without any disassembly, just thoroughly clean the area around the end of the shaft (brake clean, then compressed air) and apply a generous layer of RTV over it.

The trick to doing this is to drain the fluid level well below the bottom of the shaft, if you don't do this the fluid will continue to leak around the shaft and prevent the RTV from adhering. Allow the RTV to set before refilling with fluid.

It's worth a shot, right?  Thanks for the idea!

[RD]

A lot of people fix that leak without any disassembly, just thoroughly clean the area around the end of the shaft (brake clean, then compressed air) and apply a generous layer of RTV over it.

The trick to doing this is to drain the fluid level well below the bottom of the shaft, if you don't do this the fluid will continue to leak around the shaft and prevent the RTV from adhering. Allow the RTV to set before refilling with fluid.

It's worth a shot, right?  Thanks for the idea!

i do agree with john on that fact, but i have seen many "fixes" like this will leak eventually.  the rtv is insurance, not the preventative in this book.  remember, your trans sees a lot of different environments due to its position under the car.  RTV, exposed to these elements directly will eventually age quicker than if sandwiched between two metal pieces and gasket material (i.e oil pan and engine block).

doing it right the first time will give you the added insurance knowing that if it were to leak again in the future, it will be a helluvalot longer down the road than a couple years.

but, on that note and supporting john's advice, reapplication of RTV is simple.

[RD]

One other question, does the transmission need to be removed from the car?  I'm sure it would make the job easier; but I had a heck of a time getting it to mate up with the TQ converter and everything the first time.     I hate waiting to get someone to come around and help....   Hell, I've been waiting a week for assistance with something else, as it is!

no you do not have to remove it from the car, just remove the trans crossmember and support the trans with a tranny jack or jack stand

[grdprx]

I just broke the motor in, was hoping to drive the car relatively soon..  It won't see too many miles, so I think I'll try the RVT.  Mostly trouble shooting a few things.  Then in the fall/winter, I'll fix it.

[John_Kunkel]

Keep in mind that there are different grades of RTV; Permatex, for example, makes one intended for use with ATF (#81180) and so does Mopar. I'm sure there are others.