Originally posted by gavin123
so it doesn't matter what year borg-warner t-5 i buy. b/c i could buy any of the 5-speeds at the junkyard.
With your present configuration, 3-speed transmission, your best choice is to use the California Pony Cars adapter plate for T5 and their crossmember. To use this, you need a new transmission mount with slotted holes instead of the one with round holes you have now.
You will need:
a. T5 transmission
b. CPC adapter plate (some machine work required to fit it).
c. CPC crossmember
d. New transmission mount (slotted hole type)
e. New slip yoke (explained below).
f. New shifter handle (completely different from your present shifter).
g. Driveshaft rework (explained below).
You can use your present shifter boot, escutcheon plate for the shifter. You can also buy new ones if your current ones are shabby.
(b) above. The CPC adapter plate matches the Toploader bell housing you have now to the T5 transmission. It also spaces the T5 7/8" back from the mounting position of your current 3-speed. This is needed because the T5's input shaft is 7/8" longer than your 3-speeds. The machine shop work to fit the adapter plate to your existing bell housing is about $35.
(d) above. Although you could use your old transmission mount, slot its holes and make it fit, its much easier to buy the new mount and it fits directly. The lump on the mount faces back towards the rear end.
(e) above. You'll need a new slip yoke. Although the old one will fit, its most likely worn significantly in the area where the T5's rear seal rides. The T5 uses Dextron III/Mercon V transmission fluid that is a lot thinner than the type of transmission grease used in your 3-speed. The result of using the old slip yoke is usually a lot of transmission fluid spots on your driveway. Get a new one to avoid the mess it can cause.
(f) above. You'll need a T5 shift handle to bolt onto the top of the T5. There are many available but if you want one that looks like the original four-speed shift handle, you can get it from National Parts Depot and other Mustang vendors. This handle looks original except for the 5-speed knob on top.
(g) above. You MAY need to rework the driveshaft. Why? With the T5 spaced back 7/8" most folks find that the clearance between the end of the T5 and the slip yoke is too close. You need 7/8" clearance between the seal and the yoke part of the slip yoke. So how do I find out how much to cut off the driveshaft and how do I do it? After installing the T5, do a trial install of the driveshaft. If you can't get it in, then obviously, you need to shorten it. If it goes in but is closer than 7/8" between the yoke and the tranny tailshaft, then you shorten it enough to achieve 7/8" clearance. Hence if the clearance is 1/4" before shortening it, then you'll need to shorten it 5/8", etc. Where do I get this done? The best thing is to find a light duty driveline shop in your home town that does this work for you. Also have the shop replace the u-joints at the same time and you'll be sure of having a good, freshly balanced driveshaft.
The T5 is a pleasure to have in your car compared to the 3-speed and you'll get 10-15% better gas mileage on the highway as a result of the swap. This is a very worthwhile change. My advice is not to buy a used transmission rather buy a new one. By the time you get a used transmission, have it reworked and the update kit installed, you'll be very close to the cost of a new one. Save yourself a lot of pain and agony and install a new one.