After draining the old fluid,...
After draining the old fluid, unbolt and pry off the turret cover.
Depending on driving habits or driving style, your T5-equipped Fox-body or SN-95 probably gets more abuse than the average slushbox. Powershifts at WOT, banging gears in the quarter-mile, and pumping 400-plus horsepower through a 300hp-rated trans is usually a pretty risky combination.
Even with all of the new manual transmissions available for Mustang owners, the T5 is one of those components, like the 5L, that just keeps hanging on-or not. It used to be that the transmission, namely the T5, was the weak link in the Mustang chain, but more modern Mustangs don't suffer from such a weak component. Nevertheless, if you have a 5.0L with a T5 and you plan to keep it that way, upgrades will be in order. So when yours begins grinding into gear or growling at highway speeds, its time for some freshening up. Typically worn components that cause those noises are the blocking rings (grinding) and bearings (growling).
Beneath the turret cover is...
Beneath the turret cover is the offset lever. Using a punch, remove the roll pin that attaches the offset lever to the shifter shaft.
Transmission rebuilds, automatic or manual, are one of the jobs on most shade-tree mechanics' black list. There are many moving components, some which need to be measured with precision tools, that most are afraid they would take one apart and never get it back together correctly.
Well, we felt exactly that way when we tackled this T5. Even though I, your author, rebuilt one T5 a long time ago, I felt a strong sense of anxiety as I broke loose the first of the tailshaft housing bolts. And for good reason: I didn't have diagrams, instructions, or an experienced professional taking the reigns.
Since I had done this before, however, I knew just enough to get me in trouble. If knowledge is power, then I was a measly shoeshine boy in desperate search of a phone booth. Thankfully, a quick search through our archives yielded a Ford service manual for the T5. If you don't have a manual handy, there are some available for free online.

Under the offset lever are...

Under the offset lever are a spring and a detent ball. Take note of their location. Summit Racing's kit comes with new ones, but be sure they match.

Unbolt and pry off the tailshaft...

Unbolt and pry off the tailshaft housing.

Use a punch to remove the...

Use a punch to remove the roll pin that holds the Fifth gear shift fork to the Fifth/Reverse shift lever, and remove the fork and blocking ring.

Unbolt the housing cover and...

Unbolt the housing cover and pry it loose with a pry bar.

Remove the housing cover,...

Remove the housing cover, which houses the shift rod and forks. Clean the pieces and replace the shift fork inserts with the new ones included in the kit.

Use snap ring pliers to remove...

Use snap ring pliers to remove the snap ring that retains the Fifth gear blocking ring.

Use a two-jaw puller to remove...

Use a two-jaw puller to remove the Fifth gear synchronizer hub.

Unbolt and pry off the front...

Unbolt and pry off the front bearing retainer.

Align the flat portion of...

Align the flat portion of the synchronizer teeth with the countershaft and remove the input shaft.