I am losing oil between the adapter plate and tail shaft. I went to change the trans oil and fluid. When I draind the manual side no gear oil came out"SCAREY"so when I put new Royal Purple gear oil back in there was a steady drip.

My question is are the seals and gaskets from the manual side and the adapter plate easy to change?
Are there special tools that would be needed?

 

Possible crack around bottom bolt of trans, has been mentioned here before

 

If you do't have a Factory Service Manual for your year of car, you should get one. The tranny will have to be removed to fix any leaking issues especially the seals between the plate and tailshaft. The FSM will have the procedure.

You should be able to get some advice from S-K Speed and they may even have the necessary seals.

 

I do have the FSM, so this should be straight forward fix, no special tools. No tricks needed. Just remove bolts replace seals and gaskets and torque everything back to specs.

 

It's very likely to be a crack at the rear of the 4spd portion. Mine leaked gear oil from this same spot, it's a pretty common problem it turns out. 5speeds posted about it on here a couple times.

 

I just went though changing the overdrive on my trans.
I didn't take the trans out, i just changed the overdrive underneath it.
The overdrive weighs about the same as an aluminum 3 speed, and comes off easy.
A. you will have to remove the drive shaft and the torque arm, wiring harness, shifter, etc.
1. There is gear oil in the trans and in the adapter plate because that's where reverse gear lives. So drain the trans.
2. Then drain the overdrive unit by removing the pan, and getting rid of the fluid.
3. Buy a overdrive filter and it comes with a gasket. Put the pan back on with the new gasket finger tight.
4. Take the bolts out between the trans and the overdrive, remove the side cover off the trans. When you remove the side cover, make sure the trans is in neutral.
5. Then tap the side cover a little with a rubber mallot, gently. The cover will come loose and fall down a little, and the 4-3 arm fork will stay in the trans in it's groove. Then remove the cover.
6. Then on the left side of the overdrive where it mates up to the trans adapter just above the cast part of the reservoir, there is a groove that you can put a screwdriver in and pop the trans back to remove it.
7. There will be a clunk that you hear as the overdrive comes back. That is an idler gear on a shaft shaft that falls down about a half inch. It can't go anywhere, and there is a thrust washer between it and the idler shaft boss cast into the case. The thrust washer will be down about an inch, and you have to poke your finger in the boss, and raise the washer up so it is in line with the boss, and add a little grease to it so it stays in place, and slide a 9/16 socket in the hole to keep the washer and the idler in place.
8.There is a shaft that is pinned to the overdrive that comes with it, and when the overdrive is sitting on the floor, there will be about 10 inches of shaft poking out of the overdrive that came out of the trans that supports the idler gear.
9. When you get the overdrive on the floor, get it on a rag, and slide it out of the way.
10. There is a reverse gear with a pawl at the back of the trans surrounding the splined shaft that is about 5 inches in diameter.
11. The reverse arm stays in the adaptor, and has a short 1 1/2 inch shaft that the reverse arm slides forward and back on.
The gear stays on the main shaft, and the pawl has an arm that it rides on and the short shaft stays in the trans in it's socket.
12. You might have to slide this little shaft back in it's hole, and realign the reverse pawl. No problem, it's easy.
The gear oil will have dripped a few drips, and then you wipe the cavity clean.
13. Scrape the gasket material from the adapter, and look for the famous crack on the back bottom of the trans adapter.
14. Clean it with brake clean, and fix it with J-B Weld. Be sure to cover the entire crack.
15. After it cures, (24 hours) use a file to remove any leftover epoxy that could be on the mating surface.
16. Place the gasket on the trans, use gasket sealer on both sides, get the overdrive unit lined up with the idler shaft, and slide the overdrive back almost on.
17. Slide your hand up to the idler boss inside the 4 speed part, and make sure the socket is still in place.
18. Slide the overdrive all the way in and the socket will fall in the trans, and then remove the socket right away.
19. get a small mirror, and use a flashlight, confirm the thrust washer is in place. If the thrust washer slipped, the shaft shouldn't go back in. It won't go back in if the reverse slider shaft is out of position either.
20. If all looks good, replace the bolts and torque them to 45 foot lbs.
21. Clean the side trans cover. Get the side cover gasket, and smear it with sealer on both sides, stick it to the cover, and as gently as you can, slide the fork on the cover into it's synchro groove, tip the cover towards the tunnel, and slide the other fork back into the shifter mechanism hole, and slide the cover up into place, and install all the bolts.

Check that the arms switch gears before proceeding.

22. Reassemble all the stuff you took off of the trans, remove the pan again, and change the filter, clean the magnet, and smear the gasket both sides with sealer, and torque to 40 inch Lbs.
23. Refill the trans with gear oil till it starts leaking out the plug hole.
24. Remove the fill plug on the overdrive, and use a syringe, refill it with Dexron III till it comes out the hole. replace the plug, rotate the rear wheels a few rotations, and pull the plug again, and refill again. Install the plug semi tight.
25. Get in the car, start it up, and briefly run through the gears, and shut it off. Remember if you dilly-dally, the exhaust is heating up.
26. Get under it again, and pull the overdrive plug, and refill with Dexron III till it comes out again.
27. pull the 4 speed fill plug and insure that it's still full, and you are done.
YAY!!!!!!!


If you can get gaskets, you might be able to get them from Eckler's in an overhaul kit, or some other source.
I made a new gasket from a manilla folder, and used a really small ball peen hammer to trace the surface and cut the gasket flanges.

 

The O/d filter is same as Ford FMX auto trans

 

Thank You to all that have replied.

coupeguy2001, you are better than the FSM-Thank You.
I will follow your 27+ step process. Now time to hunt down some gaskets.