Technical T10 transmission stuck in gear, can't shift

Before you spend any money on it, take a close look at the syncro teeth on the gears. If those are rounded off, you're looking at a major rebuild. The early T10s had straight-cut syncros and due to the helical cut on the gears would start popping out of gear as they wore. Eventually they'd get so bad that shifting issues would turn up. Sounds like this one was worn out when you bought it. A 'rebuild kit' consists of new bearings and the brass blocker rings; it doesn't address the steel gears or the shift sliders (which are also probably worn just as bad as the gears). The 1 through 4 gears will be $150+ each, the two slider assemblies (which is how they should be replaced) at about $500 each, plus the rebuild kit at another $150, you'll be looking at $1800+ in just parts. There are vendors who sell 'good' used parts, but in my experience that's a crapshoot.

I will note here if you did a conversion and used the C5 truck bell and a FE-specific trans, the input shaft isn't long enough to properly engage the pilot bearing. Also make sure that if you do have an early bell, make sure you don't have a small-block type input as it can be too long and may be bottoming in the crankshaft. Either of these problems will cause shifting issues.

The newer Super T10 had redesigned syncros with back-cut teeth that 'locked in' when shifting, eliminating this issue. Ford never used that version, they had phased the T10 out by the time it came out. But Richmond Gear (the current manufacturer of the T10) does offer a brand-new Super T10 for Ford applications. You'll have to check to see if it will bolt to your early-pattern bellhousing if that's what you have.


Richmond Gear 1304000470: Super T-10 4-Speed Transmission | Ford Applications | Gear Ratios: 2.43, 1.61, 1.23, 1.00 (2.55 Reverse) | Torque: 375 ft.-lbs. - JEGS High Performance

 

The last T10 I rebuilt. The row of parts in the back are the ones that needed replacing.

 

Sounds like some of the pro's are right here ;-)
Still, tearing up a synchro while cruising in 4th sounds unlikely.. Must have been other issues that weren't addressed earlier, as stated here.
Some folks do like to cruise in 4th with their hand resting on the shifter, without the shifter stops firmly adjusted..

 

It had some issues when first installed. 3rd gear always had a hard time staying in gear, was tough shifting into first after hitting a few red lights in a row. Buddy boy sold me a lemon and said it was all good.

I saw some mustang website was selling a "rebuilt" galaxie t10 for $1200.... I'll see how much the rebuild will be though.

 

Any 'rebuilt' T10 you look at, make sure you check the syncro teeth on the gears....

 

Lesson learned!

Wish you were over here though haha