T5 Output Shaft Machining

[Mustang5L5]

Hello, I new here...hoping someone can help me with a t5 transmission rebuild. I hope its okay to piggyback on this thread.

I pulled the tranny out of my 89 5.0. The main shaft bearing surface under 3rd gear is gouged and I'm looking to replace the main shaft. I have found new and used main shafts for sale, but they all look different than mine. My main shaft has a flared tip (Not the tapered barring like on the cobras and Z trans). all others I have seen have a straight tip. I'm referring to the tip that inserts into the input shaft and rolls on the needle bearings.

No one I see selling new or used main shafts specifies a difference. Can I use a main shaft with a straight tip? If so do I need a new/different input shaft. If not where can I find an affordable replacement.

Any help you can give me is appreciated.

Your mainshaft is the oddball. That's not how a typical Mustang t5 mainshaft looks. Do you have a tag on the T-5 that can help identify it? If not, take photos of the overall case and such.

This is what the tip should look like, and also, since it's related to this thread, the mainshaft tip in this photo also has the typical galling damage that causes 1-3 gear whine

 

[MyFoxBody]

Thanks for the help.

I emailed Astro Performance to see if they could help me identify/replace my main shaft. I sent the same picture. This is the response I got back:

Your mainshaft is burnt up! Your needles in the pocket of the input shaft are most likely burnt up. And, your input shaft is most likely burnt up. I think your going to need all three pieces. You also need to look at the 3rd needle bearing, as it looks like it scarred the bearing journal on the mainshaft really bad too. The 9310 Alloy Mainshaft will work in your transmission. However, you need to address why the front of the output shaft is burning up. Usually when we see this there is a lack of fluid being directed in between the input and output shaft. Now, it is very possible that the rear tailshaft bushing is worn out. I would ask that you send me a picture of the outside of the slip yoke on the driveshaft too. If I can see that the bushing in the tailshaft housing is turning against the yoke, I will know that either an engine or transmission mount is the culprit. When either mounts go bad the rear of the transmission will sag. The driveshaft slip yoke will push up against the bushing and cause a “gouge” in the outside of the yoke. Then when your driving down the road oil is going toward the back of the gearbox. If there is an area between the yoke and bushing where fluid can get past, the oil will collect in between the rear seal and back side of the bushing and have no where to go but out the back of the gearbox. You won’t see oil puddling up on the ground in your driveway if this is the case. Just as your driving it will come out the back. I wouldn’t invest in a $400 output shaft if you don’t get the problem rectified first.
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I do believe my transmission mount is destroyed. When the transmission went out I also had power steering fluid being thrown all over the lower engine bay and down along the undercarriage. I think it slowly ate away at the the trans mount causing it to sag. It shouldn't be a problem. I'm restoring the car from the ground up and will be replacing both engine and trans mounts.

 

[Martman]

So I pulled my driveshaft to check the yoke the other day when doing some brake work. The outside of the yoke had smooth grooves in it. So I am guessing that may be an indicator of trans mount failure on mine as well. I plan on getting an aluminum driveshaft some day. But this whine and the vibration at 60mph plus are causing me headache when I look at cost. But my shifter doesn't shake or anything so I would expect more if the mount was bad.

Sent from my Nexus 6 using Tapatalk

 

[Mustang5L5]

Wow. I completely thought that mainshaft was machined that way. Now that I look at that, it's totally burned up!

I would second Astro's diagnosis and would be looking at the tailshaft bushing being worn as well. That's going to be an expensive repair though.

 

[MyFoxBody]

But my shifter doesn't shake or anything so I would expect more if the mount was bad.

My trans failed 12 years ago. The car has been garage kept (not running) since. I'm just now starting to work on her. All that said...I don't remember any signs or symptoms pointing to a failed trans mount. One day my trans locked up at 70mph. 12 years later I tear into the trans and find this. I would get under there and check the mount for any problems.

Wow. I completely thought that mainshaft was machined that way. Now that I look at that, it's totally burned up!

I would second Astro's diagnosis and would be looking at the tailshaft bushing being worn as well. That's going to be an expensive repair though.

I thought the same thing. I'v decided to scrap the trans and buy a rebuilt one. I found a guy in fort worth that sells them for $700.

Thanks for your help.

 

[General karthief]

That sounds like a good price but it's been 12years since I bought mine.

 

[broncojunkie]

My trans failed 12 years ago. The car has been garage kept (not running) since. I'm just now starting to work on her. All that said...I don't remember any signs or symptoms pointing to a failed trans mount. One day my trans locked up at 70mph. 12 years later I tear into the trans and find this. I would get under there and check the mount for any problems.



I thought the same thing. I'v decided to scrap the trans and buy a rebuilt one. I found a guy in fort worth that sells them for $700.

Thanks for your help.

I've seen him advertising on Craigslist and know a guy who bought one and had good luck. When you get it, how about posting some pics and tell us how you like it?