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T5 Rebuild Part 1 - Mainshaft Nose Woes

Starfury

Well-Known Member
Welp, finally started tearing the Astroperformance T5 apart today for rebuild. Tear down itself is going smoothly, but I'm finding things that need to be addressed.

First issue is the Reverse/5th Syncro, which has some fairly worn teeth on it on the 5th gear side. The teeth on 5th gear itself aren't perfect, but might be usable.

Second and more serious issue is the nose of the main shaft. It looks like the main shaft roller bearing surface has been worn down, machined, had a weird cap pressed onto it, and that cap walked and galled on the inside of the input shaft.

Apparently nose bearing surface wear is common on T5s. Solutions are:
1) replace the main shaft. Not an inexpensive prospect.
2) take it to a machine shop and have it machined and properly sleeved.

Open to suggestions.
 

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Ooh, that's ugly. And how the hell did someone tear up a 5th/reverse synchro?! Seems odd unless it was really high mileage.
 
The 5th synchro baffles me. Who is grinding into 5th?

After some further research, I've concluded that the "bushing" on the nose of the output shaft was pretty half-assed. I've seen a couple pictures of proper sleeves on these, and they don't look like this. They shouldn't stick out past the end of the shaft. This one did, which is why it rubbed on the input shaft.

The saving grace for this transmission is that the gears themselves are in good shape, and that those gears are Astroperformance A5 gears, including the 26-spline input shaft.

The input shaft wear does not appear to be catastrophic. It shouldn't actually interfere with anything once the main shaft problem is fixed.
I may take the main shaft to a machine shop and see what they think. I've managed to find replacements for $200, but if a machine shop can fix it properly for $50, that may be the way to go. I'm already going to need to buy the R/5 synchro set, and I'm still on the fence about the synchro teeth on the 5th gear.
 
My guess is the synchro material was severely worn to the point it wasn't really functioning resulting in bad gear mesh. Lots of reverse and 5th shifts over time, I suppose. Still not common at all. Be wary of cheaper input shafts lots of crap out there. If yours is of quality I think you are thinking correctly to see about repairing it.
 
Output, not input shaft. Input shaft is an Astroperformance piece, and the minor bit of wear shouldn't interfere with a correctly sized output shaft nose.

Unfortunately the output shaft is not part of the Astroperformance kit. The input shaft is, but their beefed up output shaft is $500, and I'm not going to be throwing that much power at it.

I think this thing was slogged at the race track, poorly rebuilt, and then slogged some more before the previous owner got it. The A5 gear install was actually done at Astroperformance (they verified their stamping on the side), but I can't see them half-assing the output shaft like this. Also, most of the synchro rings look very good, like it's been rebuilt since the A5 conversion.

I'm still going to fix it. But everything is an adventure...
 
Progress pics. Still working on tear down.

Broke the tip on my cheap snap ring pliers (ordered some Knippex pliers), and I need to bring what's left into the shop at work so I can use the press.

49E6A12F-AE01-41CE-8009-A5BF294C33E3.jpeg
 
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