NeedMoPower

I've noticed my project truck is leaking transmission fluid from the rear seal on the 727. Would anyone happen to know what size the nut is that holds the yoke to the tranny? The reason I ask is because I dont have a socket big enough and I'm going to have to go buy one.

Thanks,
Cody

dizzel

I'll bust out the calipers and check for you.

dizzel

Well the caliper says 28.3mm so I'd go with a 28 mill or 1.110 inches whatever that is.
Hope that helps
Eric

NeedMoPower

Thansk for taking the time to do that! I went to sear and picked up a socket and I'll tear into it tomorrow if I have time.

Cody

dizzel

No worries,
It was easy enough to check, I did it one handed with my boy in the other arm

Let me know how well that socket fits as I have to do the same thing
Eric

searcher

Needmopower, looking at your sig, what truck are you changing a seal in? When you pull the shaft, look closely at the leak and make sure it is coming from the seal and not from the splines. Thats where mine leaks from on the 727. Good Luck.

NeedMoPower

Thanks for the heads up. I just bought a 90 model 2wd not listed in my sig that is a very clean truck. It had no oil lieaks to speak of and then all of the sudden it started to leak tranny fluid at a fast pace after owning it for a few weeks and it's coming from the yoke/seal area. How the heck to you fix the leak if it's coming from the splines? Do you have to replace the shaft?

Dizzel...I'll be sure to let ya know how it fits!

Cody

JDGnut

Sounds like maybe 1 1/8.... a little silcone on the shaft.. or sometype of sealer..(but something that you can get the yoke off, if you have to..) If your in my area, after 5:30... someone will let you in to get what you need...

searcher

If it has been parked for a few days, chances are that the fluid drained from the converter back to the pan and rose above the splines. I think that is a problem we have because I think the later models use a solid yoke instead of a nut. Do a search for my posts. I have asked about it a couple of times. The consensus is to seal it with sealant. I haven't done it because sealant getting into the fluid is a death sentence to our transmissions, and I don't think sealant would be a permanent solution anyway with the torque on the splines.. I think it could be fixed with a trans kit that would act as a check valve to prevent converter drain back. Think positive and maybe yours will be the seal. Also that seal is hard to find. Its a dealer item or from a trans specialty shop. The ones at autozone and advance didn't fit.

NeedMoPower

Searcher, your last post made me feel better. The truck was parked for about 2 weeks before the leak started. It leaked out 1/2 -1 quart of tranny fluid and then stopped. Maybe it was just fluid draining out of the converter??
Do you just accept the fact it's going to drain fluid out if it sits for a few days since you havent used the sealnt?
I'm a complete idiot when it comes to transmissions....

rbrettctd

What he ^ said. With the 727, anytime I parked my truck for 3+ days, it would drain off a little.

NeedMoPower

What are y'all calling a little? I've got a large puddle underneath the truck.

searcher

Thats what I do. I try to at least start it every day and shift through the gears. One last thing though, since your other truck is a standard, your 727 has the fluid checked in neutral. It doesn't circulate in park.

searcher

I had my truck parked for a couple of weeks and about 3 days into it I had a big spot on the driveway. I put a pan under the yoke and in about 2 weeks it had a quart in the pan. Bad deal but I am not ready to pull the valve body until the weather cools down and I want a permanent fix when I do it.

searcher

As for wear in the shaft, I am guessing that has to have something to do with it otherwise they would leak when brand new. I just don't know why it wouldn't leak when new since the splines are never that tight and the converter was designed to drain back. I found people complaining about the same things in other Mopar forums where the trans leaks from the older speedometer cables when the cars are parked for the winter. I know mine is a static leak because there isn't a single oil spot under my truck, only on the ground where it is parked so thats one good thing.