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Ford AU T5 gearbox conversion into 1986 740T Automatic

TreeTree (@Tree) VIC South East
edited January 2017 in Articles & Guides
See my following post updated below regarding tranny fluid and noise

As promised here is a swap GUIDE for AU T5 Tremec (Borg Warner) manual gearbox into a 1986 Volvo 740 Turbo Automatic. It is not a bolt on straightforward swap and there is some minor custom fabrication involved. But it can be challenging and a real learning experience for a willing car enthusiast!
 
Please note this is not a step by step. Decent mechanical knowledge recommended.
 
Background

The standard M46 transmission that comes in 740s are known to be weak sauce. Also 5th gear is overdrive. GTFO! Out of Toyota W58, Volvo M90 or Getrag M51 the most cheapest and most accessible option is the Borg Warner/Tremec T5. It is also the most common swap in the US and popular in general. Another bonus is that the T5 is stronger , easily rebuildable with stronger or different ratios. They are sourced from manual Falcons and Commodores.
 
List of ingredients

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Volvo parts
  1. 740 Manual pedal box. Don't forget the clutch pedal pin and r-clip!
  2. M46 gearbox parts
    • Bellhousing. Require sleeve knocked out, reamed and bearing carrier machined for input shaft to fit. Alex did mine.
    • Clutch fork, pivot ball, stud, washer and nuts.
  3. 240/740 8.5" Flat flywheel. These came from the early pre-1985 model cars. Later ones came with a stepped "dish" flywheel. I opted for the flat flywheel as it is lighter so the engine revs faster. Needs to be machined and extra threads tapped. Alex did this for me.
  4. Volvo flat flywheel throw out/release bearing. Sachs 3151 190 031
  5. 740 Flywheel spigot/pilot bearing. Stock one is fine. Nachi P/N: 6003-2NSE9
  6. 740 Master and slave cylinder.
    • Slave cylinder C clip 32mm (double check). Thank god for Masters.
  7. Clutch hard line from manual 740 or fabricated. I got mine copied by a brake shop from an original.
  8. Rubber hose for clutch master to reservoir.
  9. Rear main seal. Good to do while it's accessible.
  10. Most likely need new tail shaft bolts and nuts. $12 each for OEM. $1 at bolt shop. These are shanked and must be high tensile 8.8 or harder. I had to grind mine down to fit. Need 4.
  11. Brake fluid for clutch

 
T5 Tremec/Borg Warner parts

  1. T5 from AU. The length of AU (23.8") lines up perfectly to 740 shifter location after installation of adapter plate which is 16mm. The M46 is (24.5") shifter to transmission face.
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    • T5 damper sleeve (optional). Original plastic most likely shagged. Cube speed on eBay sells a metal one.
    • Might as well get a fleabay t5 rip shifter for better shift feels
    • Tailshaft oil seal (optional). My seal looked fine so I left it. Also looks like a PITA job.
  2. Input shaft. The original AU is too short after fitting adapter plate. 93 Mustang Cobra has a different helix angle to the AU and subsequently all gearboxes back to EB. I ended up getting my shaft lengthened by 17mm. Chicks dig it. See appendix for more info.
    27244665780_ce631ff96e_h.jpg
    • Input shaft retainer oil seal
    • Input shaft main bearing - may need to replace if damaged after being exposed to heat treatment when getting it cut and shut
  3. Ford Falcon XF Clutch kit. Exedy P/N FMK-6260. We will be using the pressure plate and disc. This is the largest disc that will fit the flat flywheel and should handle quite a bit of power. eBay has the best prices. Disc is 10 Spline same as AU input shaft.
  4. Shifter stick and knob. Ripshifter already comes with stick.
  5. Dexton III Auto oil. Just get the 4L


I sourced all my bearings and seals from Eastern Bearings, cheap and Travis is super helpful!

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Metal "damper sleeve" cup to replace plastic one
 
Fabricated/custom parts:

  1. M46 to T5 Transmission adapter plate $220 depending on quantity. Alex ("veeque" @ ozvolvo) can supply this locally. Email: Disintegraterperformance@gmail.com
  2. A gearbox mount will need to be made using a 740 automatic transmission cross member. Welding involved.
  3. Modified tail shaft to fit new gearbox. It needs to be shortened, balanced and the front converted to T5 spec. cheaper if you supply the splined Ford T5 U-joint. About $200-250 at the local driveline shop. Measure twice cut once.
  4. The M46 bellhousing needs to be machined suit adapter plate.
  5. The section where the clutch fork and release bearing mounts on the T5 needs to be machined to accept the bellhousing. Bit vague here Alex did the work lol.


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Adapter plate

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Gearbox mount fabbed up

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Drive shaft
 
Process

It's been a while since it the swap was completed. Except for removing the original gearbox this can be done in a flexible order. It's probably the same as re-installing a manual except with a few extra steps thrown in. Two people are recommended when lifting gearbox.

  1. Disconnect battery
  2. Disconnect neutral wiring
  3. Drain and remove auto gearbox. Plenty guides out there on how to. If you crimp the lines right it shouldn't leak too much.
  4. Remove auto pedal box
  5. Test fit input shaft with adapter and bellhousing. It should stick out roughly 1.5cm. As stated before I got my original AU one lengthened by 17mm after buying wrong input shaft twice. This seems to be the only way for now.
  6. While input shaft is getting done or waiting on parts you may choose to change the damper sleeve bush cup and upgrade to Ripshifter while the gearbox is out. Check out this video for step by step.
  7. Assemble M46 bellhousing, input shaft, adapter plate, pivot ball
  8. Test fit the gearbox and measure length required to modify the tail shaft. Remove and send it off to get done.
  9. Install new rear main seal, pilot bearing. The key to installing oil seals is to get a mechanic friend to do it.
  10. Install flywheel and clutch. Tighten to torque specs
  11. Install tail shaft.
  12. Fabricate a mount between gearbox tail end and automatic cross member.
  13. Install the gearbox and fill with Automatic Dextron III oil
  14. Install master and slave cylinder and clutch lines
  15. Install clutch fork and release bearing
  16. Fill, flush and bleed the clutch system.
  17. Re-connect neutral wiring and install shift knob
  18. Double check everything is done
  19. Go for your well rewarded test drive.
  20. WIN!


Cost all up around $1900. can be done for maybe a bit cheaper if omit the ripshifter or started with manual car etc.

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Epilogue

Initial impressions. I like it. No, I love it! Mostly because I love driving manual. I like to shift fast and sometimes it doesn't get into 3rd as smooth as I'd like. This is with the metal bush installed but not Ripshifter. Ripshifter should improve the experience. Not too different compared to the M46 to be honest. The gear ratios are taller than M46. Good for cruising but maybe not for 0-100. Solution: MOAR BOOST. Will update in a few months.
 
Thanks to everyone who contributed on the T5 thread: found here T5 gearbox conversion
  • Alex (@Vee_Que) - helped me swap my tranny and supplied a few crucial ingredients
  • Jay (@blondejay)
  • Nicko (@nickm)
  • Bob
  • Anthony Hyde
  • Rick122


Helpful links when opening the transmission



Appendix A: Input shaft

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Left to right: BA, AU, 93 Mustang Cobra, BA V8

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AU Input shaft before

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AU Input shaft after being lengthened

The issue I faced was that the AU input shaft was too short after the adapter plate was installed. We tried the 93 Mustang which had the right length but that uses a standard square cut bearing. Next we tried the 93 Mustang Cobra and which had the right height as well but the gear helix angle was off by 4 degrees.

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See the difference?

In the end I decided to get the input shaft cut, lengthened, hardened, and shut by Gear Repair in Sydney. Took them 2-5 business days. $190 plus shipping, very reasonable!

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Modified AU - 237.5mm length

Input shaft specs:
  • AU T5
  • 10 Spline
  • 220mm length
  • 147mm shaft installed with retainer
  • 167mm transmission face to shaft end


'93 Mustang Cobra input shaft specs:
  • 10 Spline
  • 9.25" 235mm
  • 14.5mm longer than AU


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AU and Cobra with same "tapered" bearing style

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Cobra vs Standard 93 Mustang with weaker roller? bearings

Appendix B: Gearbox choices

The AU is the only T5 to date that lines up almost perfectly to the 740 original shifter location. The BA is 24.5" from the transmission shifter to face and will be further back after installing the shifter plate. I barely managed to install ripshifter with my AU IN CAR so I assume BA might be easier as there's two bolts that are hard to reach. BA also uses a larger clutch than the Volvo flat flywheel and is 27 spline. The VS Commodore box used in Jay's car is too short at 21.5" and he had to grind a bit of the transmission tunnel for it to fit.
Another thing to note is that the Ford T5s use a tapered bearing which is supposedly stronger because it can handle more torque.

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AU T5 no gearstick

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Jay's VS T5 with ripshifter.

Alex's comments:
If you are to use a stock flat flywheel, you get another type of disc to go with the volvo pressure plate, and if you go with a dished flywheel, the disc size is 230mm not 235mm and due to its design loses pressure as the clutch wears, increasing wear and slip when driving. Yoshifab sell a disc but its also available from exedy as a disc only. Unsure on the part number. And I do the redrilling and balancing. No one else seems to in Australia, to suit us.
Second, you can't physically fit a 4L BA pressure plate and clutch, as they are 245mm and that's the total size of the flywheel! The bellhousing for a BA is integrated, so you can't use the bearing carrier and machine it down. But you could buy an XF pressure plate and the fine spline clutch to suit something else I guess.
bgpzfm142

Comments

  • nickmnicko (@nickm) Sydeneee --- home of the traffic jamb, over priced coffee, and the 2000 Olympics
    Thanks for going the extra yard...
  • Vee_QueVee_Que (@Vee_Que) South Eastern suburbs Melbourne.
    Disintegraterperformance@gmail.com sorry, email is wrong. And clutch disc size is off the top of my head.
  • Good technical article.

    What is the weight of the T5 gearbox ?

    You fitted to a 1986 740 - could you state what engine management is being used. Thinking LH2.2 so you don't need a flywheel with 58 hole pattern.

    Therefore later year model 740/940 owners who have LH2.4 might / will need a Plan B for a flywheel, as a 58 pattern is required for 2.4. for the engine management system. Or move to a after-market computer.
  • Great article Sam, does anybody know how much horse power that clutch could take?
  • Great work. Is it possible to add an appendix with information on this gearbox swap for 240s?
  • Thanks a lot for taking the time to write this up @Tree ! Will be going this route in a few months myself, and Alex I'm sure will be an invaluable resource yet again :)
  • TreeTree (@Tree) VIC South East
    edited June 2016
    My pleasure guys! Just worked on the article bit my bit for a while then compiled it because there's so many fragments of information. I'm all about sharing :)

    @Anthony Not sure about T5 weight but quick google search says 75lb= 35kg. Feels about 40kg with bellhousing. Probably lighter than AW71 for sure!

    @mculling I considered the V8 AU box but V8 has long ass gear ratios compared to the I6. AU I6 is 160kw fly and AU V8 is 220kw fly. Never seen an AU V8 box to compare size either.

    Should be plenty of AU boxes around I got mine for $350 (inc $30 core charge) from a diff mechanic that listed on gumtree. Much more common than BA boxes imo. BA T5s get swiped by the P platers and other "classic car" conversions use ELs or whatever so AU T5s are a lonely orphan (not anymore haha!). Look everywhere gumtree, ebay, wreckers etc

    @GingerNinja sorry mate I don't know about a 240 but the 240 shifter position is closer to engine so AU would be too long/far back. Easier to just get just a 740/940 Turbo haha.
  • Vee_QueVee_Que (@Vee_Que) South Eastern suburbs Melbourne.
    V8 AU was 175kw and from there they ended up at 220kw on the tickford models.
  • jamesincJames (@jamesinc) Oz Volvo Ice Fortress
    Dear readers: please direct questions regarding this article to the following thread: https://ozvolvo.org/discussion/4551/ford-t5-mt-conversion-meta-discussion

    If you have questions or want clarification on the article from @Tree, please ask them here.
  • Out standing write up.Just what I and some other guys need on here also...

    Cheers
  • TreeTree (@Tree) VIC South East
    A small update!
    1. If you change the input shaft bearing, check the preload before fitting the box!
    2. T5s seem to be a noisy bunch
    3. Lubrizol 7906/Penrite 4297 additive is recommended to add in with ATF III. 75w85 Gear oil can also be used instead of ATF.

    T5 are known to be noisy, however the rattling/chatter sound that is prominent in 5th gear at 100kmh and above when accelerating hard or decelerating is driving me nuts! I can only describe the noise like a small loose bolt or screw vibrating violently in a metal box just large enough to fit it. I spoke to the gearbox/diff mechanic which I bought the t5 from about this issue and he said it could either be extra noisy due to missing factory damper or incorrect input shaft bearing preload.

    There is a factory issued metal damper that fits in the tail section of the T5 which shuts up some of the noise and vibrations fitted to some models.. I have given this a shot but to no avail.

    Next up is pulling the box out and checking the preload. I changed the input shaft bearing but did not check the preload. Or it could be something internal which the T5 mechanic will cover under warranty yay! I will report back the findings.

    Secondly, Lubrizol 7906/Penrite 4297 additive is recommended to add in with ATF III. ATF is great for synchro operation as it is thin, but offers less "cushioning" for the gears. This additive helps with that. Otherwise the gearbox/diff mechanic said he uses 75w85 which is harder to shift when cold but offers more protection to the gears. Penrite even recommends 75w80 on their website for BTR T5 transmissions. This might help shut up the noise a bit too.
    bgpzfm142
  • Vee_QueVee_Que (@Vee_Que) South Eastern suburbs Melbourne.
    I said to use tge penrite 75/85....
  • Excellent thread cheers

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