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T5 Modification

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T5 Selection and Modification

There has been a lot of confusion regarding which of the Ford T5 transmissions would be considered the best for the Alpine V6 Conversion.  The confusion is brought about by the differing gear ratios typically used with stock Mustang V8 vs. V6 versions of the T5, and the "personal preference" of the owner.

Due to the high RPM range of the 2.8L V6, some of the V8 versions of the Mustang T5 could produce slightly better performance if used in conjunction with an optimum rear end gear set.  The table below is derived from AllFordMustangs.com and identifies the various T5 specifications which are appropriate for this conversion.

A T5 Transmission from a Ford Mustang - If your intention is to make an ultimate racing Alpine, the preferred transmission is from behind the 1986 to 1993 5.0L V8 Mustang coupled with a 4.11 or 4.22 rear end ratio that you might install with a shortened Ford 8".  (This is due to slightly higher 1st and 5th gear ratios).  The higher 1st and 5th gear transmission ratios are offset by the lower ratio of the rear end.

If you are not taking your Alpine to the drag strip, the -220/-226/-238 T5's are a great choice with the Alpine stock rear ratio's.  The V6 transmissions probably have not been abused as much as the V8 versions, and therefore may not require a rebuild.

The chart below identifies various T5 applications and their specifications.  The choice of your transmission is a personal preference, dependent on how far you plan to take your conversion and your desire when it is complete.




B/W Id Source Application Torq Max (lb/ft) Gear Ratios Input Shaft
length
1352- Year Model Engine 1st 2nd 3rd 4th 5th R
220 Factory 94 Mustang 3.8 265 3.35 1.93 1.29 1 0.73 3.15 7.85
236 Factory 94 1/2 Mustang 3.8 265 3.35 1.93 1.29 1 0.73 3.15 7.85
238 Factory 94-97 Mustang 3.8 265 3.35 1.93 1.29 1 0.73 3.15 7.85
126 Factory 85 Mustang 5 265 3.35 1.93 1.29 1 0.68 3.15 7.18
141 Factory 86 Mustang 5 265 3.35 1.93 1.29 1 0.68 3.15 7.18
165 Factory 86 Mustang 5 265 3.35 1.93 1.29 1 0.68 3.15 7.18
219 Factory 94 Mustang 5 300 3.35 1.99 1.33 1 0.68 3.15 7.85
169 Factory 86.5-89 Mustang 5 265 3.35 1.93 1.29 1 0.68 3.15 7.18
199 Factory 90-91 Mustang 5 300 3.35 1.99 1.33 1 0.68 3.15 7.18
208 Factory 92-93 Mustang 5 300 3.35 1.99 1.33 1 0.68 3.15 7.18
246 Factory 94-95 Mustang 5 300 3.35 1.99 1.33 1 0.68 3.15 7.85
218 Factory 93 Mustang Cobra 310 3.35 1.99 1.33 1 0.68 3.15 7.18
242 Factory 94-95 Mustang Cobra 5.0 310 3.35 1.99 1.33 1 0.68 3.15 7.85
115 Motorsport 79-83 Mustang 5 305 2.95 1.94 1.34 1 0.63 2.76 7.18
200 Motorsport 79-93 Mustang 5 305 2.95 1.94 1.34 1 0.63 2.76 7.18
227 Motorsport 79-93 Mustang 5 325 2.95 1.94 1.34 1 0.63 2.76 7.18
249 Motorsport 79-93 Mustang 5 33 0 2.95 1.94 1.34 1 0.63 2.76 7.18
204 Service 85-89 Mustang 5 300 3.35 1.99 1.33 1 0.68 3.15 7.18

My personal choice was the 1352-000-238 T5 as used on 94-97 Factory Mustangs with the 3.8L V6 & had ratios of 3.35,1.93,1.29,1,0.73 with the longer input shaft.


Note that the Input Shaft Length on some of the V8 models are about 5/8" shorter than others.  A T5 with the 7.18" shaft requires the Jeff Kelly - Pilot Bearing Adapter to extend the pilot bearing and compensate for the shorter input shaft.  AS NOTED BELOW: The shorter shaft does not require modification, however you will need to use a Type 2 pilot bearing adapter which may be purchased from Jeff Kelly .

The long shaft T5 does not use Jim Kelly's Pilot bearing adapter, instead a bushing should be installed in the flywheel similar to the OEM Ranger setup. 

1. Mustang II flywheel and the long T5 input shaft - use a bushing in the flywheel
2. Mustang II flywheel and the short T5 input shaft - use a Jim Kelly Pilot bearing adapter
3. Ranger flywheel and the long T5 input shaft - use a bushing in the flywheel
4. Ranger flywheel and the short T5 input shaft - Machine the flywheel and use Jim Kelly's Pilot bearing adapter

T5 Modification


The bearing retainer supporting the input shaft (Item #60 below) is slightly larger than the bell housing opening. The best way to make the two fit is to remove it and turn the O.D. to fit the hole in the bell housing. Details of this modification are found below.

Before you begin the T5 disassembly, note that care should be taken as you remove the retainer from the front of the transmission, so you don´t drop any of the bearing rollers from the front bearing, into the transmission case. This can be avoided by tilting the transmission slightly nose down when you remove the collar. To mount it again, use a little light grease to hold the rollers in place as you reassemble it.

The description below is copied from the T5 Service manual:

T5 Disassembly


3-14. REMOVAL OF T5 WC INPUT SHAFT.
  1. Make alignment mark on input bearing retainer(60) and transmission case (117) and proceed as follows (see figure below)
  2. Remove bolts (59).
  3. If necessary, use suitable knife to break sealant bond between input bearing retainer (60) and transmission case (117). Pull bearing retainer straight out.
  4. Use suitable puller to remove oil seal (61) from input bearing retainer (60).
  5. Remove shim(s) (62) and bearing cup (63).
  6. Rotate input shaft (65) to align flat on its clutch tooth ring with countershaft (116) and remove from transmission.
  7. If necessary, remove bearing cone (64) from input shaft (65) using suitable puller.
  8. Remove pilot bearing between input shaft (65) and output shaft (101) as follow, depending on bearing type:
    • Individual Bearing Rollers. Remove 15 bearing rollers (66A) and spacer (67).
    • Roller Bearing Assembly. Remove bearing assembly (66ยช ).
  9. Remove thrust bearing (68) and thrust race (69) from end of output shaft (101).







Modifications to the Input Shaft:


T5's earlier than 1994 have a shorter input shaft than post 1994.  The shorter shaft does not require modification, however you will need to use a Type 2 pilot bearing adapter which may be purchased from Jeff Kelly .


The input shaft on 1994 and later years is long enough to engage the pilot bearing if it is not pressed in to its full depth.  These later version T5's will require the end of the input shaft which engages the pilot bearing reduced from its original size of .666" (17mm) to 0.588" (15mm) (+/-0.0005") as shown below.

The T5 Input Shaft (65) is induction hardened steel.  The end of the shaft needs to have the end turned and polished, or ground to fit the pilot bearing.


Shaft turned on center for concentricity
using carbide cutter or grind
Chamfer the shaft end 0.06" for lead in & leave 0.06"
radius at transition to larger diameter to relieve stress
Shaft reinstalled after tuning end to 0.5885" diameter




Modifications to the Input Bearing Retainer:


The large diameter of the Input Bearing Retainer(60) is aluminum, and needs to be turned down to mate with the opening in the Bell housing.  Care should be taken to ensure it is maintains concentricity with the throw out bearing extension.  This surface is what centers the bell housing with the T5 transmission.

The Bell housing ID is 4.850" as shown below.  To mate with a slip fit, the Input Bearing Retainer Large diameter should be turned to 4.846" +/- 0.001".

Additionally, if your T5 should happen to have a long throw-out bearing tube, you will need to cut it down to make the overall length 4.5" from the T5 side of the flange to the end of the tube.  


Shortened and OD sized bearing retainer


Bell housing opening for the bearing retainer

 





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