broncojunkie
Well-Known Member
A year or so ago, I was in the market for a good used t5 for my 88gt. Didn't want to spend a lot and it was basically stock, so I didn't need anything crazy. I had trouble finding a good used v8 fox body t5. Seems they're all pretty much ragged out already. So after some research, I picked up a later model Tremec stamped t5 from a 99 v6 Mustang. They put these transmissions behind the v6 from 99-04, iirc.
The difference between these and the fox body version, most notably, is the electronic speedo and the different bell/input shaft/input shaft retainer. Using your old bellhousing is straight forward. Easy enough. The input shaft and retainer can be swapped from your old fox body t5, provided they are in good shape. For mine, I opted for a new, upgraded steel retainer. My input shaft was good, so I re-used it. This would also be a good time to replace the needle bearings, if they aren't in great shape. Mine were fine. Replace the input shaft first, while you have the case opened up. That way, if you end up dropping needle bearings down inside the case, they'll be easy to get to. You'll need to set the end-lash on the input shaft retainer, but that can be done after it's all together.
The biggest hurdle was the speedo drive gear. The main shaft in the newer t5 still has the provision for a mechanical speedo gear, although, you'll have to drill a small hole for it's retainer clip. The plastic gear just slides into place, but the retainer clip is held in place using a small lip that inserts into a hole drilled in the shaft itself. Sounds easy enough, but it's not. The t5 shaft is made of hardened steel. I'm not an expert on types of steel and the different hardening processes, but I can tell you that pretty much all of the suggestions I found did not work. Cobalt/carbide bits would barely scratch the surface. In the end, I was able to grind a very small hole using a dremel with a diamond engraving bit and lots of oil. The process still took about 30 minutes or so.
The electronic speedo set-up consists of a sensor installed in the side of the tailshaft housing. Unfortunately, this sensor is not located in the correct position to just use the hole for your speedo driven gear. So you'll need to swap the tailshaft housing for an old one, which has the correct hole you need to attach the speedo cable with the plastic gear. On the newer t5, there is also a plastic ring on the mainshaft/tailshaft, which works with the electronic sensor in the tailshaft. This ring simply slides off and won't be needed.
Here, you can see the difference in tailshaft housings. You can see the electronic speedo sensor in the very bottom of the pic on the left. That's the tailshaft housing from the v6 tranny. The freshly painted one on the right is the old tailshaft attached to the new v6 t5.
The new t5 went together with no major hiccups. When it's all done, you'll have a fox t5 which has the same torque rating as the later world class fox v8 units (around 300 ft-lbs, iirc).
I cleaned it up inside and out and gave it a quick coat of paint.
(The bellhousing you see in the pic is from the 3.8 v6, which wasn't being used. It comes in handy as a stand for when you need to set the t5 on it's end to work on it...or paint it).
The difference between these and the fox body version, most notably, is the electronic speedo and the different bell/input shaft/input shaft retainer. Using your old bellhousing is straight forward. Easy enough. The input shaft and retainer can be swapped from your old fox body t5, provided they are in good shape. For mine, I opted for a new, upgraded steel retainer. My input shaft was good, so I re-used it. This would also be a good time to replace the needle bearings, if they aren't in great shape. Mine were fine. Replace the input shaft first, while you have the case opened up. That way, if you end up dropping needle bearings down inside the case, they'll be easy to get to. You'll need to set the end-lash on the input shaft retainer, but that can be done after it's all together.
The biggest hurdle was the speedo drive gear. The main shaft in the newer t5 still has the provision for a mechanical speedo gear, although, you'll have to drill a small hole for it's retainer clip. The plastic gear just slides into place, but the retainer clip is held in place using a small lip that inserts into a hole drilled in the shaft itself. Sounds easy enough, but it's not. The t5 shaft is made of hardened steel. I'm not an expert on types of steel and the different hardening processes, but I can tell you that pretty much all of the suggestions I found did not work. Cobalt/carbide bits would barely scratch the surface. In the end, I was able to grind a very small hole using a dremel with a diamond engraving bit and lots of oil. The process still took about 30 minutes or so.
The electronic speedo set-up consists of a sensor installed in the side of the tailshaft housing. Unfortunately, this sensor is not located in the correct position to just use the hole for your speedo driven gear. So you'll need to swap the tailshaft housing for an old one, which has the correct hole you need to attach the speedo cable with the plastic gear. On the newer t5, there is also a plastic ring on the mainshaft/tailshaft, which works with the electronic sensor in the tailshaft. This ring simply slides off and won't be needed.
Here, you can see the difference in tailshaft housings. You can see the electronic speedo sensor in the very bottom of the pic on the left. That's the tailshaft housing from the v6 tranny. The freshly painted one on the right is the old tailshaft attached to the new v6 t5.
The new t5 went together with no major hiccups. When it's all done, you'll have a fox t5 which has the same torque rating as the later world class fox v8 units (around 300 ft-lbs, iirc).
I cleaned it up inside and out and gave it a quick coat of paint.
(The bellhousing you see in the pic is from the 3.8 v6, which wasn't being used. It comes in handy as a stand for when you need to set the t5 on it's end to work on it...or paint it).
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