Continued
GM F-Body
GM used the T-5 in F-body cars behind all engines. In general, the I4/V6 got the following ratios:
1st – 3.50 2nd – 2.14 3rd – 1.36 4th – 1.00 5th – 0.78
Although some 4-cyl cars got the 3.76 gearset as used in the S10 & a few V6 cars actually got the 4.03 gearset.
The V8 F-bodies typically got the following Gearset:
1st – 2.95 2nd – 1.94 3rd – 1.34 4th – 1.00 5th – 0.73
It’s worth noting again that the ’93-95 F-body V6 cars got a Ford case with a GM input shaft. There were no V8 T-5 during these years.
Tag Numbers
V8 2.95 NWC – 028, 062, 070, 072, 157, 185
V8 2.95 WC – 159, 160, 175, 176, 195, 196
3.50 NWC – 015, 027, 061, 156
3.76 NWC – 054, 083, 158
4.03 NWC – 181
4.03 WC – 177
NWC Other (unk app/gears) – 071, 084, 150, 166, 178, 182, 183
WC Other (unk app/gears) – 197, 212, 213, 214
WC Ford Pattern – 210, 245, 247
ADAPTING THE T-5
Shifter Placement
The Mustang and F-body T-5 both have rear mounted shifters at the end of the tailshaft. These often make difficult swaps and shifter placement, particularly in early Fords, is untenable.
L-R Early Ford Toploader, S10 T-5 w/Adapter, Mustang T-5
The S10 T-5 is often selected due to the shifter placement (approx 7” further rearward than early Ford), but typically lacks desirable gear ratios or the increased strength of a WC unit. Because of the T-5 excellent interchangeability, the tail housing and top cover from an S10 can be swapped onto other T-5. There are a few issues when doing this.
The first is a small plastic oiling funnel found on the countershaft and retained by the tail housing. These are different from WC to NWC, but it is primarily due to changes in the tail housing casting, not an internal oiling issue. Consequently, this plastic funnel should stay with the tail housing. So, use the S10 plastic funnel when swapping an S10 tail housing onto a WC T-5.
T-5 Countershaft Oiling Funnels
The second issue is that of speedometer gear. Typically, when installing an S10 tail housing and top cover onto a WC T5 from a Mustang or F-body, the speedo gear will no longer align with the driven gear mounting hole in the housing. The output shaft has a built up area where the speedo drive gear mounts with a clip. Moving the gear requires building up the output shaft with shim stock. An excellent example of how to do this is found on the inliners websit at:
http://www.inliners.org/Jack/T5tech.html
Finally, if putting an S10 tail housing onto a Ford T-5, you will probably have to change the tailshaft bushing for the Ford one. This is due to different diameters of the output shaft.
Adapters
Adapting a GM (pre-’93) T-5 to any other GM product is pretty straightforward. Just find a bellhousing that will accept any standard Chevy-style transmission and bolt it all up. You’ll have clutch linkage to sort out, but putting the trans behind the engine is easy.
Adapting a Mustang T5 to a post-64 Ford bellhousing is pretty straightforward too. A thin, flat-plate adapter used by the early Mustang crowd is all you need. However, the easiest solution is to use the bellhousing from a late-model 5.0 Mustang – no adapters required.
65-Up Ford Adapter
Adapting a Mustang T5 to a ’49-64 Ford bellhousing is also relatively easy. The bottom two bolts line up well, one top bolt will need to be re-drilled, and the other top bolt will likely need an ear welded onto the bellhousing to finish it all off.
When adapting a GM T5 to a Flathead Ford, there are several options. Offenhauser makes two adapters – one for the early, internal clutch linkage and one for a more modern clutch fork. Speedway sells their own version of these adapters for a little bit lower price. Cornhusker also sells a complete kit with the adapter and other items (like pilot bushing, input shaft sleeve, etc).
Speedway Clutch Fork GM Adapter
Another option is to use a machined flat plate and the “hogshead” or mini-bellhousing from a ’46 and up Ford truck 4-speed. Dwight Bond (eBay ID 007Dwight) in Gibbon, NE sells these for very reasonable and you’d be hard pressed to buy the material and pay for the machining for what he asks. He also has the special pilot bushing and input shave sleeve. There are also plans for the flat plate available from George Greenbaugh (eBay ID community-chest) for the hard-core do-it-yourselfers.
Dwight Bond Flat Plate Adapter on Hogshead
To use the Ford pattern T-5 behind a flathead is a bit more work, but a company in New Zealand, Mac’s Speed Equipment, builds this adapter. Their webpage is:
http://www.macsspeed.com/adapters_2.html I believe Vern Tardel also makes an adapter to use the Ford T-5 behind a flathead.
Input Shafts
As mentioned, input shafts vary by application and there are three general sizes, Ford, Chevy V8, and small Chevy. When adapting the T-5 to a flathead, or many other early engines, the input bearing retainer where the throwout bearing rides may be too small if using the original throwout bearing. A simple sleeve-type adapter can be used and are easily made by any competent machine shop, or readily available either in kits from Speedway or Cornhusker, or separately from Dwight Bond and others.
Clutch Disks
As a rule of thumb, any clutch disk that has the correct input shaft size/spline count and correct diameter for the pressure plate will work. The Astrovan clutch disk seems to be popular when doing the flathead conversion, but check the clearance on the flywheel retaining bolts. Some clutch disks will not clear the bolt heads and cause problems later on. The very best option is to have the correct center hub installed on the flathead disk by a good clutch rebuilder.
Shifters
One of the T-5 weak points is the stock shifter. There are no positive stops on the shifter itself, so it is easy to “over shift” the transmission. This can cause bending and cracking of the shift forks and is most notable when really banging the gears hard. This flexing of the shift forks will result in damage to the synchros. One of the best things you can do, especially if you like to shift hard or fast, is to use an aftermarket shifter with positive stops that are correctly adjusted in accordance with the manufacturer’s recommendations.
Shifter handles can be modified simply by cutting off the original shifter and welding on the handle of your choice to the stub. Some shifters are two-piece with a rubber isolator that can be torn off and a new handle welded on. If you use a Mustang transmission, the shifter handles merely bolt on to the stub.
Throwout Bearings
Which throwout bearing to use will depend on specifics of your swap. If you’re running a flathead in an original Ford frame, it may be best to use one of the adapters that allows you to retain the stock clutch linkage and throwout bearing. This will provide the neatest solution.
Hydraulic slave cylinders are easily adapted in both push and pull configurations and may be the best way if building from scratch or using a less common setup/swap. In this case, use a throwout bearing that will readily adapt to your linkage. In some cases, you may have to sleeve the input bearing retainer, while in others, you may use a T-5 OEM throwout bearing.
Hydraulic throwout bearings are also available, but reviews and results are decidedly mixed and they tend to be quite pricey.
MISCELLANEOUS
Rebuilding
The T-5 is as straight-forward as most other modern manual transmissions and require a minimum of specialized tools. Two excellent resources are available online, the Borg-Warner Technical Service Manual here:
http://www.ttcautomotive.com/English/media/pdfs_autogen/T-5_Service_Manual.pdf and a good how-to rebuild manual here:
http://pomoforacing.com/tech/T5Rebuild2002.pdf
Endplay is the key to any manual tranny and the T-5 is no exception. Shim packs are still available from Ford and small parts kits are available from several sources online.
Oil
All NWC T-5 use 70WT Gear Oil or Redline MTL.
ALL WC T-5 use ATF.
Do not use gear oil in a WC T-5. Use a quality synthetic oil (regardless of which type you need to use) & change it frequently (every 15-20K). Fill to the fill plug – about 5-1/2 pints or 2-1/2 quarts.
Open Drive
For a flathead conversion, you’ll probably need to convert to an open drive setup. Hot Rod Works and Speedway, as well as several others, sell a conversion kit for your banjo rear. Alternatively, you can swap to a modern rear like an 8” or 9” rear. You will need to replace the torque tube with some sort of locating device if modifying your banjo – the stock radius rods simply aren’t up to the task.
Closed Drive
While I haven’t done it yet, I am in the process of converting a Jeep T-5 transmission to accept the torque-tube and stock early Ford U-joint. This should require crossmember modification, spline adapter, flat-plate adapter to accept the bell mount, and shortening the torque-tube/driveshaft. I will post this on the HAMB when I complete it. Who knows, maybe I’ll produce a kit if I’m successful!
Jeep T-5
RESOURCES
The following is a list of various websites. Most are pretty good, nearly all also have errors (like I’m sure this article does too). Most errors, are errors of omission that can lead to misunderstanding or confusion, however, there are some errors of fact on many of these pages.
http://www.vanpeltsales.com/FH_web/t5_fivespeed.htm
http://www.flatheadv8.org/t5-swap.htm
http://www.moderndriveline.com/Technical_Bits/t5_history.htm
http://www.jalopyjournal.com/forum/showthread.php?t=169265
http://www.5speeds.com/t5/index.html
SOURCES
Jim O’Clair, T-5 Transmission Swaps, Hemmings Muscle Machines, July 04
Hokey Assed Message Board,
http://www.jalopyjournal.com
Inliners International Board,
http://www.inliners.org
POMOFO Racing,
http://pomoforacing.com/
Transmission