Fresh T-5 pops out of 5th gear only

[90topdown]

I have a fresh rebuild T-5 (less than 100 miles).

Today was the first day that I had a chance to get it out on the expressway. 1-2-3-4 all shift great but when you are on the highway it pops out of 5th gear after 3 or 4 mins. I put it back in 5th and it is fine for 3-4 mins and it pops out again. If I leave it in 4th everything is fine.

It doesnt grind going into 5th, it just pops out after 3-4 mins on the highway.

It is full of synthethic Dexron and I have a B&M Ripper ST shifter.

Any ideas before I take it back to the tranny shop for the second time on a fresh rebuild

Previous problem turned out to be a bad 3-4 synchro which he fixed for free.

 

[Mustang5L5]

shift stops in 5th gear set too tight??

 

[90topdown]

There are 2 shift stops on the shifter. One in the front and one in the rear. Both were backed out all the way. It is a B&M Ripper Sport shifter

I removed the shifter. Everything looked ok. The little plastic cup was there. Re-installed shifter.

With the engine off, I ran the shifter thru the gears. It clicks nicely into 1-2-3-4 and reverse. When I put it into 5th it feels a little floppy and there is no click. You can move it in and out of 5th gear with 2 fingers on the shifter. Any other gear, you have to grip the shifter to get it in/out of gear.

This shifter worked fine for 3 years on my old tranny so I don't think that is the problem.

Is this definitely a tranny problem??? I'd like to be sure before I take it back for the second time.

 

[Mustang5L5]

Sounds like it to me. Something in the shift rails doesn't seem like it's installed right. It should def "lock" into positon when you shift

 

[jrichker]

Each synchro assbly has 3 "keys" that serve to hold the syncro in the engaged position. The "keys" look like small metal
boxes and are held in place by a wire spring inside the synchro assembly. My guess is that the spring has slipped out of
place and the "keys" no longer have spring tension on them to hold the synchro assembly in the engaged position.

46 is the spring
47 is the sleeve
48 is the "key"
49 is the sychnro hub

See TTC: Product Literature 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 – Adobe - Adobe Reader Download - All versions

See Hanlon Motorsports - T5 and Tremec parts, sales and service or
D & D Performance for parts

A T5 rebuild kit with syncros, bearings and other small parts costs about $160. It does not include any gears or shafts.

Hanlon Motorsports - T5 and Tremec parts, sales and service 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.

 

[90topdown]

You are probably right as the first time it went back it was for a bad 3-4 synchro.

Spoke to the tranny guy. He was a bit incredulous as he just finished rebuilding the second time, but he said to bring it back and he would look at it. I'll take it back after the holiday.

Thank God I got the 12 mo/12,000 mile warranty with it.