Broken Input Shaft. T5 Is Knocking 1st 2nd 3rd Gear

Inmy88gt5.0 · Aug 10, 2017

1988 mustang gt 5 speed t5

2 weeks ago while driving home my t5 started to knock. I suspected low transmission fluid so I drained it (it had about 1 quart) and filled it up back up. Took a drive into the next city on my way back the knocking returned louder than before so I drove it home parked it and lifted it. I thought maybe it was leaking oil (I replaced the rear output seal 1 month ago) after dropping the transmission and removing the the tail housing and top plate I found that the input shaft and a chunk yes a chunk of teeth missing. Also noticed I'm missing the needle bearings but I do have some bearing on the main shaft?) shim, and race? Transmission worked good before occasionally popped out of 2nd gear no problems besides that.

Knocking quiets when clutch is disingagded but is still present.

Will replacing everything on the front end of the tranny(including bearing retainer) fix the knocking? Or is it too late.

I will post pictures tomorrow

General karthief · Aug 10, 2017

So, you put it back together without fixing it?
Time for a rebuild or up grade, if you stang is stock, rebuild it, if not up grade.

jrichker · Aug 10, 2017

See http://www.ttcautomotive.com/lit_oem.php to download a FREE service manual for T5 or Tremec 3550/TKO
You will need the Adobe Acrobat viewer which is also a free download – http://get.adobe.com/reader/

See http://www.hanlonmotorsports.com/ or http://www.ddperformance.com for parts

A T5 rebuild kit with syncros, bearings and other small parts costs about $250-$350. It does not include any gears or shafts.

http://www.hanlonmotorsports.com/ also has a video on how to rebuild your T5 or Tremec. It costs about $20, and is worth every penny of it.

I did a Tremec 3550 rebuild, and it wasn't that difficult. The video was an immense help, and I would recommend viewing it. At $20, it will give you an opportunity to look and decide for yourself if you think that it is something you want to try to do.

Alternate sources for the T5 rebuild video...
https://www.google.com/search?sourc...30j0i22i30.0.0.0.9710...........0.Mz886XmDDt4

T5 Shim kits – best product I have seen in a while… http://www.5speeds.com/t5/shims.html
“The Peel ‘n Place T5 World Class shim kit makes shimming T5 counter gear and main drive gears very easy.”

For Tremec 3550 and TKO's:
You will also need a magnetic base and dial indicator to measure the endplay ($40-$120). http://www.mscdirect.com P/N 06444129 cost was approximately $57 + shipping as of Feb 2013

The tricky part is that you will need some shims to adjust the endplay in the two shafts: the new bearings will change the clearance. There is no way of telling what it will be until you get to the point that it is time to measure and check the clearances. Halon has the individual shims if you can wait for them. If you can't afford the wait, the auto parts store can sell you some shim stock and you can make your own, or have a machine shop make them for you. The shim stock comes in brass (easy to cut) and steel, in varying thicknesses. That's where the dial indicator & base come in - there is no way to get the clearance right without it.

Getting the car jacked up high enough to get the trans jack in and out from under the car was somewhat challenging. Since I didn't have a helper, getting the trans out of the car and back it was one of the more difficult things about the job. I built a trans jack out of 2x6's, some angle iron and a $25 floor jack. If I hadn't done that, I would have needed a helper or to rent a commercial trans jack. At 100+ pounds the Tremec 3550 was far too heavy for me to lift by myself.