'08 GT 5-sp trans leak

Lannyl81

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Hello,
New member....my daughter returned to our city after almost 5 yrs and so I once again get to work on her Mustang.
Has just over 97k miles on it and has been problem free for the most part...but now it has a trans leak and I have not been able to determine from exactly where from.
I think it is the tail housing output shaft seal. I cleaned the tail housing, then went for a short drive, got back under it and the tail housing again has an oily film coating. Just not sure if the oil is leaking down from the shifter area, the speed sensor, or is indeed the output shaft seal and the oil is just being blown/thrown forward when driving.

Hopefully someone here has been through this and can tell me.

Only thing I know to do would be to get the Mustang on 4 jack stands and run it, watch the trans to see if I can see the where the oil is coming from.

Thanks in advance.
 

Jason Dowdy

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I will almost bet it is the shift shaft seal. Just went through this myself. I changed the output seal and it kept leaking. Finally changed the shift shaft seal and it fixed it. You will need a good pick and patience to remove it. Use a socket to put it back on. And Ford couldn't get one anymore. Rockauto actually had one and I crossed the number and got it at Oreily's.
 

golkhl

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When you change the seal, drain the trans and refill it with 3.2 quarts. I have tried a number of different gear oils in my 08 Bullitt over the last 13 years and 70k miles, currently running syncromesh.
 

Lannyl81

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Hey Jason, can the shift shaft seal be changed with the trans in the car?
 

rocky61201

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Hey Jason, can the shift shaft seal be changed with the trans in the car?
Yes you can. I've never tried it but you might be able to do it with the shifter shaft in place. If you can't get it out and over the shifter shaft , then you can still remove the trans tailshaft cover (13 bolts IIRC). From there you can even service everything in the tailshaft, and shifter shaft seal itself.

Just unbolt the driveshaft and remove the trans crossmember and let the transmission droop but still support it with a jack or block of wood or something.
 

Lannyl81

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Got it. Shifter seal ordered as well as the output seal. Going to be next week before they are both here. Fine with me....in the 110°F all week...not a good time to be in the garage.
 

Lannyl81

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I have looked through several TR-3650 service manuals and not a one of them show this shifter seal.
Also do not see how the tail housing can come off unless the shifter box assembly is first removed...and that requires driving out a pin, removing a spring plate, etc. How in the world can this be done?
 

rocky61201

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All of this can be done with the trans still in the car. I have done it when I broke the lock ring that retains 5th gear on the output shaft.

You are correct none of them covers the shifter shaft seal but this one does cover the bearing that is in there as well. I don't know how that bearing could ever fail but there is a needle bearing in there and there is a seal trust me.

Sorry I failed to mention the shifter assembly has to come out as well as disconnecting the driveshaft and removing the tailshaft flange as well which is probably the hardest part. Use an impact to remove the large nut and then a puller to get the flange off. Next step is removing the 12 or 13MM screw on the top of shifter linkage assembly. It is a pain to get at it up in the trans tunnel, but a short stuby wrench will do the trick. (See pic below) Be carefull when reinstalling this bolt as this part of the linage is soft aluminum and it can split if you over torque it.

From there slide that part of the shifter linkage off the shaft, then remove the 12 bolts for the tailshaft cover. Remove the tailshaft cover and then you have full access to replace the shift shaft seal and also access to everything in the tailshaft. You can also inspect the magnet for shavings and change the fluid while you're at it.

pic 1.jpg
 

Attachments

  • TR3650 Gearshift Rail Bushing.pdf
    96.3 KB · Views: 5
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rocky61201

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Here is every service manual I have on the TR3650. This is the 2006 and up version. Not the TR3650 used in previous generations of Mustangs.
 

Attachments

  • TR3650 Assembly.pdf
    1.2 MB · Views: 9
  • TR3650 Countershaft Bearing.pdf
    92 KB · Views: 7
  • TR3650 Disasembly.pdf
    1.5 MB · Views: 7
  • TR3650 Gearshift Rail and Fork.pdf
    45.8 KB · Views: 6
  • TR3650 Gearshift Rail Bushing.pdf
    96.3 KB · Views: 5
  • TR3650 Input Shaft and Bearing.pdf
    82.2 KB · Views: 4
  • TR3650 Output Shaft.pdf
    1.3 MB · Views: 5
  • TR3650 Synchronizers.pdf
    36.1 KB · Views: 5
  • TR3650 Tourque Specs.pdf
    11 KB · Views: 8

rocky61201

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Thought about it some more. The shift shaft seal if very small and sturdy and at the very top of the transmission and very little fluid makes it's way up there, but I suspect the main reason this shift shaft seal can go bad is old age, lots a miles, and excess vibration from other components that have gone the same route. Motor mounts, transmission mounts, shift linkage rubber and plastic bushings, driveshaft vibration, etc. etc. etc. You might want to spend some extra time and inspect everything related if you're planning on keep the car for a long time.

If you want a really great and cheap upgrade for the shift linkage bushings get these.

Amazon.com: AMP Tr3650 T5 Bronze Remote Shifter Bushing Kit: Automotive
 
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Lannyl81

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Thanks Rocky....I think all the TR3650 manuals I have viewed are for the older version...as the shifter area is quite different between the two.
I have planned on removing the driveshaft and the output flange, draining the trans as well as I doubt the fluid has ever been changed.
I previously looked at those bronze bushings....and would like to get them...but not knowing what daughter's plans are for the Mustang....would probably be throwing the $50 away.

Thanks again....waiting for seals to arrive.
 

SPeace-ATL

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This may not be as simple as a leaky seal...

The TR3650 is NOTORIOUS for developing a crack in the extension housing just in line with the cross member. The leak will run to the rear lust like a bad seal, so be thorough with the examination and fix. This is true for both the 2001-2004 style as well as the 2005-2010 style. I will say I see it much more in the 2001-2004 units though. With the crack there is usually a vibration in the drive train at high speeds. Often, the drive shaft needs to be replaced with a one-piece aluminum shaft after the extension housing is replaced.

Now, something I tell anyone that is removing that flange. I always reinstall the flange by placing the whole transmission in my shop press, but others can't do that so they use the nut to draw the flange back on the tail. If you don't follow the procedure you will ruin that rubber seal under the nut when forcing the flange back on with the nut and then have a leak inside the flange.

Okay, here is the trick: When reinstalling the flange you have to first LEAVE OUT that rubber seal. Use only the nut and washer to carefully draw the flange back on. Then, when it is fully seated, you REMOVE the nut and washer, install the rubber seal, washer and nut and then torque the nut.

Should you find a crack in the extension housing there are no new housings available. You can locate one on an old transmission core, but honestly, if you catch the crack early enough you can get it welded. The weld will reinforce that area and in my opinion it will be stronger than new.

Enjoy!

Stan
 

SPeace-ATL

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What I just said about installing the flange WAS COVERED in the Service Manual "TR3650 Assembly" pdf posted above in steps 57, 58, and 59 but it is not clear as to why you would want to "forget" to install the flange seal the first time and go back and install it later...
 

Lannyl81

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Actually it makes more sense that the extension housing is cracked more than either seal leaking...just from how the ATF is all over the housing.
Plan is to get the Mustang on four jack stands, clean off the housing really well...then run the engine while I watch the extension housing.
I am planning on removing the extension housing anyways...

Seals have arrived...guess I get started tomorrow....and gee only 115°F today....
 

Lannyl81

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So.....got the Mustang on jack stands, wiped-off the extension housing, removed all wheels. Started the engine and ran in 2nd gear while watched...and watched....and watched....may be a bit of wetness on the output seal edge...may be. Stopped and let it cool-down.
got back under and unbolted the driveshaft from the output flange, pry'ed the driveshaft off the flange and got a nice dribble of ATF on me. Guess this is from the output flange nut seal....which appears to be the source of the leak.
Now I need to find this seal.
Think I will go ahead and pull the flange off, replace the output seal since I am this far.
 

rocky61201

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Sounds kinda like what Stan from pro-forceperformance.com said above. Maybe the previous owner removed the flange and didn't follow the correct procedure when putting it back on. Or it just went bad.

If you have a hard time finding a new seal (rubber washer) then contact Stan at the link above. He will send you one. Shipping might cost more than just the rubber washer, lol. But at least you won't have to buy some generic rebuild kit that includes tons of stuff you don't need just to get a rubber washer. He can also send you just the larger output seal you need as well.
 

SPeace-ATL

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The Ford flange seal is a 4R3Z-7E397-A
The Ford Tail seal for an 05-10 is a 4R3Z-7052-AA

I don't know if Ford still offers these or not, but I think they are readily available.
 

Lannyl81

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Thank you for the FORD part numbers. So far have had no success in finding this seal online. Sent Stan an email yesterday; going to call around today, see if I can find one locally.
 

Lannyl81

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Quick update: none of the Ford dealerships near me have the flange nut seal, they all would have to special order it. I just ordered one online, be here mid next week.

I got the output flange off...was not all that difficult, used my 3-jaw puller. Tried a short time to get the output seal out with no success....really need to get a seal puller for this; which I will this weekend.
 

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