Overdrive transmissions Are a Great Thing.

Overdrive transmissions are a great thing.

They enable you to significantly improve the gearing and acceleration of your car while maintaining gas mileage and highway cruise-ability. Unfortunately, overdrives, manual or automatic, weren’t offered in Ford vehicles until the late ’70s. But that doesn’t mean you have to be stuck with the non-overdrive C4’s. C6’s, and manual 4 speeds of the ’60s. Swapping in a late-model overdrive transmission, namely the T5 manual and the AOD automatic, is a straightforward swap for 289, 302, 351 equipped cars. In fact, on most early Fords, the swap is so easy it makes you wonder if Ford was thinking ahead. In this article, we’ll go over what it takes to swap in a T5 transmission into an early Ford. In future articles we’re going over an AOD swap for early Fords, and also an AOD to T5 swap for late-model Mustangs.

 

Slight clearancing of the shifter opening in early may be required. We had to do it on our ’67 Mustang, but in a ’65 the T5 lined up perfectly.

 

 

 

Swapping into early Mustangs, Falcons, Mavericks, and Pintos is easy because the hole in the transmission tunnel for the shifter is in about the same spot on all the cars. The swap is also easy for Fox body cars such as the Granada.

For other Fords, namely the full-sized cars, the swap is a bit more difficult because the engine is placed farther forward in relation to the driver. Ford used modified shifters and/or longer tail housings to set the shifter back for the original transmissions in these cars. Unfortunately, there is no such modification we know of for T5’s.

We can move the shifter forward for 8″ for the Falcons, Rangers, and hotrods.  We call it a front shift T-5.  We have plans to over a custom tail shaft housing to move the shifter anywhere it needed.

If your car is currently equipped with a non-overdrive manual transmission (Ford 3spd, 4spd, or Toploader) the swap is as simple as a clutch job, you can use your existing clutch and flywheel, but you’ll need a cross member and possibly a slip yoke and driveshaft as mentioned below. For cars with automatics, you’ll need to first install a clutch pedal and round up the clutch activation parts (either manual clutch linkage or a cable-operated clutch.)

Can do a hydraulic setup as well.

We’ve seen the T5 in several Falcons and Comets originally equipped with column shifters. The owner had to punch a hole in the transmission tunnel and fabricate a longer shifter and/or replace the bench seats with bucket seats.

With a front shift T-5 the bench seat can remain, and the floor support is left in place.

Most Ford cars sold with automatic transmissions have factory stamped holes in the firewall for the clutch pushrod or cable.
Usually, a hard tap from a mallet will knock the stamp out.

Good place to plug us with the parts we offer for the different apps.

Cobras, hotrods, 2×4 trucks just to name a few.
I checked out James Duff’s website and will be doing some business with him on the 2.9Ls.
Ford Bronco and Ranger owners, jamesduff.com sell adapters to bolt the T5 to 2.9L and 4.0L engines.

 

Toploader and T5 dimensions
Transmission	A	B	C	D	F
Ford Toploader (small block)	6.375	13.25	25.375	n/a	5.5
Ford T5	6.9	14.5	24.7	15.4	5.5
Overall length (A+C)	Toploader: 31.75 in. T5: 31.6 in.

 

 

 

Where to find a T5?
The T5 transmission is a manual five-speed transmission manufactured for Ford, by Borg Warner (now Tremec.) The T5 was offered in Mustangs, Thunderbirds, Capri’s, and possibly other Ford vehicles from 1983 all the way up to 2004, but you have to be careful -there are different specifications for 4-cylinder, 6-cylinder, and V8 cars. What you want is a T5 from a V8 car, ideally a Mustang. The 1983-1989 V8 T5’s are rated at 265 ft/lbs. of torque, while the 90-93 T5’s are rated good to 300 ft/lbs of torque (93 Mustang Cobra T5 is rated for 310 ft/lbs) The difference is in the internal components and also the gearing. See the chart below for gearing differences.

Good place for a link to your chart.  I can provide a very detailed list.

1994-1995 T5’s are as desirable because the input shaft length and thus bell housing depth were changed to accommodate the new SN95 Mustang body style. If you do come across one of these “dirt cheap” the input shaft can be replaced with one from an 85-93 3.35 first V8 T5, but it’d have to be a really good deal (read free) to go through the trouble. You can purchase a spacer plate so the input shaft does not have to be changed. Finally, we should mention that the T5 is also called the “World Class T5”, but many people incorrectly believe the term World Class refers to a stronger type of T5. World-class has to do with a designed change that added needle bearings under each main shaft gear, switching from bronze shift synchro rings to steel-lined rings.  In 1985, Borg Warner Ford T5’s are “World Class”, so don’t rely on that term to indicate the type of T5 you have. The best bet is to find the T5 attached to the car, or with reliable evidence of the car, it came out of. If that fails, look for the stamped aluminum tag hanging of one of the tail shaft bolts and use the ID chart to identify the model. Copy the numbers down and call D&D or Hanlon and beg them to tell you what year it’s out of.

We can provide this information on your website as well as ours.  You can mention us as well and provide the photo from the buildup we did use the front case race just under the input bearing retainer.

While it is best to shoot for the 90-93 T5 due to its increased torque capacity, you shouldn’t pass up a good 83-89 T5, especially if you’re engine is not heavily modified.

Four-cylinder T5s can be upgraded with V8 gears or G-Force

We’ve found that T5 strength and longevity is more a factor of its condition and mileage rather than its torque rating. A used, high mileage, Cobra T5 will probably shift poorly and give out much sooner than an earlier T5 that came out of grandma’s car.

Not sure what you are you trying to say here

The T5 in Project 11.99 was bought from a wrecked 1990 Mustang 5.0 with 50,000 miles. We’ve had it in the car for nearly five years now, over 400 passes at the strip, and it shifts as crisp as it did on day one.

By the way, always take the bellhousing and block plate if they are available. The T5 swap can be done two ways, using a T5 bellhousing or using an early Ford manual bellhousing. It is much easier and cheaper to use the T5 bell, we’ll explain why below.

You might want to say why you might want the T-5 bellhousing over the stock four-speed, like the cable or no adapter plate, or they are available new.

What to pay?
Used T5’s can be bought for as cheap as $100 out of a wrecking yard, however, we rarely ever see Mustang 5.0’s in public wrecking yards, most of the cars go to specialty dismantlers. You’re better off searching the classifieds and online Ford bulletin boards for guys parting out their Mustang, or perhaps upgrading to stronger transmission wanting to sell the T5 cheap. A fair price for a used, but not abused, less than 80K T5, is between $300 and $500. Any more than that and you should consider buying a rebuilt/refurbished T5 for around $700 from places like D&D or Hanlon. If you want to be extra safe you can buy the T5 new. Both the above sources, as well as Ford Racing Parts and Summit Racing, sell brand new T5 “Z” spec transmissions. The Z spec. transmission is rated for 330 lb. Ft. and sells for around $1300.

What parts are needed?
If you are converting and automatic car to a manual or five-speed, you’ll need to round up the clutch pedal and associated parts. For early Fords, this can be tough. Your best bet is to find a wrecked car that has the manual parts and take everything. Some of the smaller pieces, such as springs, bushings, z-bar, and mounts are still sold through Ford or Mustang parts houses. For late-model Ford using a cable operated clutch, all you need is the brake and clutch pedal assembly.

T5 Crossmember – Regardless of whether your early Ford came equipped with an automatic or manual, you will need a conversion cross member because the mounting pad of the T5 (and AOD) hangs much lower than other Ford transmissions. Companies such as Modern Driveline (see contacts below) sells cross members for early Mustangs, and possible Falcons and Fairlanes. They cost about $150. The other option, if you have access to a welder, is to make one yourself for considerably less money.

Slip Yoke and Driveshaft- The T5 requires a 28-spline slip yoke. The slip yoke from C4’s, C6’s will work since they are 28 -spline. Most Toploaders slip yokes will work, however, some came with a 25-spline output shaft so be sure to count. Fords originally with 3 and 4-speed manuals will require a slip yoke swap. Driveshaft length in early uni-body Fords will typically not require modification, however, you should ensure there is 3/4″ to 1.5″ of space between the base of the slip yoke and the end of the tail shaft housing (not the seal!) when the car is on the ground. Distances greater than this will require a longer driveshaft, distances less than this will require shortening of your existing driveshaft.

Clutch and Flywheel – If your car is already a manual, simply use the existing clutch, flywheel, and throw-out bearing. You should change the pilot bushing to the late model Mustang pilot bearing. Since you will need to remove the clutch and flywheel to install the T5 block plate, you may as well take the opportunity to install a fresh clutch.

If your car was an automatic you will need to get a flywheel that matches the balance factor of your motor. All 289’s use a 28 oz. balance factor. Early 302’s up to the late 1970s also used a 28 oz. factor, but after that point, Ford switched to a 50 oz. balance factor. If you mix and match the flywheels (or harmonic balancers) your engine will vibrate itself to death! So be sure you only install the flywheel with the correct balance factor. A good machine shop can convert the more common late model 50oz. flywheel to a 28oz. balance factor for around $50. The 50oz. flywheels are also drilled for the larger 10.5″ diaphragm clutch, which the 28oz. flywheels must use the early style 10″ three-finger clutches.

Stock 28 oz. and 50 oz. flywheels have 157 tooth ring gears measuring 13.294″ outer diameter. Some 351W engines, and aftermarket flywheels, have a larger 164 tooth ring gear which has a 14.215″ outer diameter and accepts an 11″ clutch. The larger clutch may not clear the inside of the T5 bellhousing.

Starter – The starter from any ’85-’92 Mustang 5.0, auto or manual, will work. The ’93 and up Mustangs use a high-torque starter which saves weight and space but costs about $120 more than the standard type. The starters from early 289-302 Ford with automatic transmissions also work, however, starters from manual transmission cars of this era seem to have a slightly larger mounting lip and don’t fit unless you mill or grind this surface down. Your best bet is to use it as a core at the parts store.

Neutral Safety Switch- Automatics have a neutral safety switch so that the car can only be started in park. For a manual, you do not need this, and the switch must be by-passed, or the motor will not start. On early Mustangs, the four-plug harness sticks out of the firewall above the master cylinder. Two of the wires control the reverse lights, the other two control the neutral safety switch. Splice two of these wires together and you’ve bypassed the neutral switch. Which two wires? You’ll need to use a voltmeter or take a couple of guesses to find out! On other cars, you can check the wiring diagrams in a shop manual or trace the wires from the original automatic shifter. The backup lights can be made to work by connecting the other two wires to the two leads on the T5 case.

Speedometer Cable and Gear – Your existing speedo cable will work, provided it is the right length. Ford surprisingly didn’t change the design of these things from car to car. You may need to re-route the cable to get it to reach the entry hole at the rear of the T5 case. You will however need to put on a T5 speedo gear, available from your Ford dealer, in a variety of tooth counts to match your differential gear and tire combo. Swapping the new gear on simply requires removing the c-clip and pulling the old gear off and sliding the new one on.

Bellhousing Modification – The T5-to-bellhousing mounting pattern is different than that of other Ford manual transmissions. This means you need to use a T5 bellhousing, with a minor modification, or you need to buy an adapter plate that sandwiches between the older (Toploader) style bellhousing and the T5. The preferred method (cheaper, easier, stronger) is to simply get a T5 bellhousing. The adapter plates are machined out of aluminum and cost $200 or more and can result in an alignment problem. The T5 bellhousing however is about 1″ deeper than the earlier Ford bellhousings (because the T5 had a 1″ longer input shaft). Furthermore, the T5 bellhousing is set up for a cable activated clutch fork. You can certainly keep it this way, but it will require modifying your clutch pedal to accept a clutch cable.

We opted to stick with the early-style pushrod activated clutch fork, this requires making a minor modification to the T5 bellhousing. You will need a 2″x1″x1″ aluminum or steel block and also the fulcrum (the piece the clutch fork pivots on) out of your early bellhousing. Sacramento Mustang, Mustangs Unlimited, and CJPony Parts sell the spacer block, fulcrum, and bolts as a kit for approximately $40.

For early Fords with manual clutches, you’ll need to install or transfer the fulcrum style clutch fork from a four-speed or top loader bellhousing. Due to the longer input shaft of the T5, you need the 1″ spacer block under the fulcrum. Available from Windsor Fox, Mustangs Unlimited, and others. The hair clip shown at the top holds the fork on the fulcrum, don’t leave it out!

 

To modify the T5 bellhousing, you need to first remove the cable activated clutch fork and fulcrum. Simply pull the clutch fork up and it will come off its clip. Then unbolt the pivot ball. The next step is to mount the mechanical style spacer and fulcrum. The fulcrum and spacer sit exactly 1″ from the rectangular opening in the bellhousing. On the T5 bellhousings there is a little oval casting that sits between these two lines. The edge of the spacer basically needs to be mounted right up against this casting, but NOT on it. Mark two lines from each corner of the rectangular opening extending to the center hole where the transmission mounts. Both these lines should be parallel to each other, and exactly straight!

Now place the spacer in between the two lines. We have determined the spacer should be one inch from the edge of the rectangular opening, up against (but not on) the oval casting mark. Mark the holes and drill. If you want to double-check our measurements before drilling, you can tape the fulcrum and spacer in place and attach the clutch fork. Then mount the bellhousing on your T5 and check that the clutch fork can pivot without rubbing the input shaft or the rectangular opening. Mount the fulcrum on top of the spacer and bolt it in place. (Note, the spacer kit we obtained from CJ Pony parts came with countersunk Allen bolts. We didn’t want to deal with drilling countersunk holes, so we simply replaced them with standard hex-head bolts.

If you mounted the spacer in the correct spot, the hex heads will not interfere with the transmission case. Finally, you will need to hack off the tab on the bellhousing directly in line with the clutch fork opening. This tab is used to mount the clutch cable and will interfere with the lower pushrod for the manual clutch. You only need to hack or grind off 1/2″ or so off the edge, this way you still have the mount in case you ever want to convert to a cable-operated clutch.

Modern Driveline
www.moderndriveline.com
208-453-9800