TR3650 Shift Shaft Seal?

[1950StangJump$]

Recently did the tail shaft seal, but I think the shift shaft seal is also seeping . . .

Is this easily serviceable with the trans in the car? I'm having a hard time imagining how the seal would go on with the shift shaft in place, and I can't find a DIY anywhere.

 

[rocky61201]

I've rebuilt the 3650 a few times and I'm guessing it's possible to do in the car. Driveshaft flange and the tail-housing has to come off. Then remove/pull fifth gear/synchro/shift fork assembly and then drive a couple other shift fork pins out and the shifter shaft should be free and clear to slip out so you can replace the seal.

You may have to unbolt the crossmember and lower the transmission while still attached to the engine. Just so you don't have interference from the transmission tunnel when using your tools to remove the stuff mentioned above.

That's a lot of work for a small seal that's high up on the transmission when all of the fluid is in the lower half of the transmission. I believe you that it's leaking, but I would probably choose to live with it until I could do a complete rebuild. The reason I say this is because you are probably going to break the 5th gear lock ring when removing it. That's $15 bucks right there and they almost always break when removing it or trying reinstall it. They are truly a one time use lock ring. Then add in the other costs, silicone gasket masker for the tail-shaft, and new transmission fluid. Also, you will need a heavy duty lock ring removal pliers to get that lock ring off. It's a bitch. A pair of snap ring pliers won't do the job.

 

[rocky61201]

Shit, I should just delete that entire post above. Once you remove the tail-shaft housing, you can replace the seal. Nothing else has to come off from inside the transmission.

 

[1950StangJump$]

Shit, I should just delete that entire post above. Once you remove the tail-shaft housing, you can replace the seal. Nothing else has to come off from inside the transmission.

Thanks. But, even that makes it not worthwhile, IMO. I was hoping I'd read that you just need to unhook the shaft linkage from the shifter, lower the trans a little by loosening the cross member, and the seal would slide down the shaft and off. Assembly being the opposite, of course.

If it ain't that easy, I don't think its worth messing with. I definitely don't want to removed the tail shaft housing or even the yoke.

 

[nawagner]

Yes, you can do it with it on the car. All you have to do is pull the link off, pull the old seal, and push the other back in. Simple, right?

It's about a 10 swear word job. If you have a 90 degree pick you can get under the seal enough to pull it out by pulling on each side a bit. Problem is, once you start there is no turning back. I think to get it back on I used a deep well socket about the same diameter as the seal to get it shoved back on.

 

[1950StangJump$]

Can you expand on "pull the link off"? Assuming you can overcome the issue with the seal being tough to dislodge from the hole . . . how do you remove the linkage that is obviously way too bulky to allow the seal to slide over?

 

[rocky61201]

nawagner is right now that I think about it. The shifter linkage is attached to another shifter linkage with a bolt on the top you can't really see unless you look for it. Remove the bolt and slide it off. After that all that's left is the shifter shaft and you are free and clear to slide the old seal off and slide the new seal on...................if you can get the old one out with a pick.

 

[1950StangJump$]

Okay, thanks.

Last question .... even if I loosened the cross member and drop the trans a few inches, I shouldn’t lose fluid that high up, right?

 

[rocky61201]

If the car is on jackstands and you are on your back with your head right underneath the tailshaft then transmission fluid will definitely leak out.

 

[1950StangJump$]

If the car is on jackstands and you are on your back with your head right underneath the tailshaft then transmission fluid will definitely leak out.

So, not to be argumentative, just want to be sure we are on the same page . . .I know fluid leaks out from the tail shaft when you pull that seal -- experienced it first hand.

But, the shift shaft seal is above the transmission fill plug. Fluid will still leak out from the shift shaft?

 

[rocky61201]

I was just joking but I know what you're saying. Fluid should not come out.

Every time I'm underneath a car, any car, it doesn't matter what I'm doing, something is always going to find its way into my eyes, up my nose, or in my mouth because I'm usually cursing.

I found a pic of that linkage thingy you have to remove with the bolt on top.

 

[1950StangJump$]

I was just joking but I know what you're saying. Fluid should not come out.

Every time I'm underneath a car, any car, it doesn't matter what I'm doing, something is always going to find its way into my eyes, up my nose, or in my mouth because I'm usually cursing.

LOL, after I wrote my reply, I reread yours and started wondering if you were joking. Thanks for the info.

 

[nawagner]

You guys are both on the right track. Only one bolt, and no fluid should come out. However every piece of dirt that has been accumulating on your car since it left the factory will be wiped off directly into your eyes. That's good for at least half of the swear words.

 

[1950StangJump$]

LOL, you guys have it good.

For me, I will not be able to get that top bolt off, then the old seal won’t come out, then I’ll score the trans case getting the seal out, then the new seal will be the wrong part number, and the car will be out of commission for a week while I resolve all this crap.

Then, the new seal will leak too, but I’ll only discover that a week later when I’m really tired and grumpy.

 

[1950StangJump$]

What a pain in the a$$ that was!! I ended up removing the trans cross member and dropping the transmission a couple of inches onto a jack stand. Getting all the linkage off was easy.

But . . .

The old seal really fought me. And, as noted earlier in the thread, once you start picking at it, you are at a point of no return. A couple hours in, I was already starting to plan for towing my car to a mechanic for him to give it a try.

Then, thank God, the seal popped loose after I had sufficiently mangled it. The new one went in much easier -- I lubed it down with Synchromesh and used a deep well 17mm socket over it. Then, I used a pry bar against the socket (pushing on the driveshaft yoke) to push it home.

The old one was definitely leaking before I ever touched it. I suspect that the driveshaft seal I replaced a few weeks back was never the source of the trans fluid seepage -- the fluid from the shift shaft seal does flow down and drip right in the same spot the driveshaft seal would.

 

[nawagner]

That's a pretty good write up, and now that you mention it I do remember dropping the cross member to lower the transmission.

I've come to the conclusion car repair difficulty is inversely proportional to the cost of the part!

You'll be glad to have it done.

 

[1950StangJump$]

Hey, thanks. I appreciate everyone's help.

 

[Anti]

I approve that standard of measurement of difficulty. My header replacement job happened at the same time I replaced my clutch, it was nawagner's used exedy now that I think about it iirc, tail shaft seal, intake, h pipe, and o2 sensor extension. Oh and motor mounts. That HAS to be a couple thousand worth. Lol

Edit. Did my rear main seal then too.. I was still fighting tightening my headers that sunday night needing to drive the car that monday. Needed to do intake and tune also.. I almost threw a match in the car. No joke. Now i'm glad i didnt though. Lol love the changes.