T-5 Transmission Rebuild

The 5 speed automatic that came with the 65 fastback had some assembly required when I received it. Well, it was actually a couple of boxes of parts. Someone before me was rebuilding it and ran into some issues, leaving it for a project. Fortunately, the project also came with a good DVD on how to rebuild a T-5 transmission.

I should have started with a picture of just how disassembled it was, all in a cardboard box for the small parts, and a Rubbermaid bin for the big ones. Lost opportunity for appreciation just how many small parts there are in this thing.

I started by watching the video up to the point where I felt I should be playing along as he started assembling. I am positive I could not have done this without it. How To Rebuild the World Class T5 Transmission

The previous owner already had all of the rebuild kit, including new gears. That left very little for me to invest in other than time, so I sat down and started following the directions. On the down side, when I was done, I had a nearly completely assembled transmission on the floor of my office, in front of my computer. Maybe time to invest in a screen for the shop.


Along the way, there was a lot of mentioning about a World Class and a Non World Class version of the T5. That got me thinking of ensuring I have the WC version and following up on exactly what did this thing come out of in case I need to buy things for it later.

There is a bunch of info out on the Internet about identifying a T5. I am not sure all of it is correct, but I did find a few points repeated which seem to hold water.

Casting numbers don’t mean much. The one number that seems to narrow things down a bit is the casting year. It is found in a few different places and looks like this:DSC_3122

The 88 in the center of the little circle says this was manufactured from an 1988 casting. So, its at least 88 or newer.

Another thing I still had was the data plate/tag.DSC_3123

I haven’t decoded everything yet, but the key number seems to be the one on the bottom left: 13-52-169. Googling for T5 decodes will come up with this page near the top. It says this transmission came out of an 86-89 Mustang 5.0.  So far, that lines up with the casting as well. Also, that page corroborates that this is a WC since it’s newer than 85, among other key identification points. Good to know, but I still don’t know exactly what it came from.

The last marking that narrowed it down was the partial VIN stamped in the edge of the bottom of the main box.DSC_3119

Back to Google, and I found the SVO Club of America page on Mustang VIN stamping. It says the K is 1989, and the F is all Mustangs. The rest is the serial number. From there I can pretty much guess the rest and build the original car VIN. I took some guesses and plugged it into Carfax to see what it did. Conveniently, it said I didn’t have a valid VIN, but it was close to another it suggested. Something seems slightly off with the SVO page for body style codes. I plugged the new VIN from Carfax into an online decoder and it came up as a valid VIN with a reasonable configuration. So the transmission originally came out of a 1989 Mustang GT hatchback with a HO 302: 1FABP42EXKF120611

At this point, I still need to get a new tail bushing and seal. The yoke is grooved, so I need a new one of those too. I hear I should get those together and make sure the bushing fits the yoke before I press it in. Good enough for now to go back to the slightly smaller pile of parts in the garage.

The Second T5

The 65 project came with 2 transmissions. Stuff accumulates over time, and opportunity affords upgrades. Before the GT version, the previous plan looked to be a 4 cylinder  version of a T5. While I have come this far, I might as well figure out what that one is as well. It will surely make it easier to sell.


It looks pretty much the same as the other one. Note the torx head in the retainer bolt in the center of the case. I understand that indicates WC.


This case casting is also in 88.


The tag says it’s a 162 which decodes to a 87-88 2.3 Mustang. No conflicts so far.


The front counter-shaft bearing race looks like the first transmission’s. Also one of the tells for a WC.


And the last clue, the serial number. J is 1988, F is Dearborn, so Mustang.  Working things out a bit, I come up with 1FABP40A3JF288279 as the VIN. It came from an 88 Mustang LX 2.3L inline 4. The gearing is going to be sub optimal for someone building a V8, but maybe someone with an I6 would use it.


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