Decoding rear diff
Soo... blew up my rear end racing. Sigh. Trying to rebuild. I killed the spiders and the spring plates.
I have some questions..
WFC bu - funky, just like a BT but not 3.45, instead 3.27. Auto vs Manual? Can't find BU in the ford registry thing.
4c16 1984, March 16th
3L27a 3.27:1 axle ratio w/ Traction-Lok
what is the a about?
7 5 7.5 ring
S276E no clue what that is about.
Is the original traction loc an auburn? Having a hard time finding parts.
1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
Comp cams XE254H, hypereutectic pistons
Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.
F
1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
Comp cams XE254H, hypereutectic pistons
Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.
Weird.....no WFC BU listed here....... http://www.fordification.com/tech/rearends_ford07.htm
Scotty
1985 Fox Notch 4-banger Ranger tube header Eastwood Royal Blue
1988 Fox LX 5.0 AOD Vert BBK 170mph speedo Candy Apple Red
1999 Mustang Coupe V6 Auto Chrome Yellow -Daily Driver.
Past Pony's.....
68 Coupe Inline-6 3-Speed-Man. Primer
78 II Hatch 302 3-Speed-Auto Sunroof Black
81 4-Eye Coupe 4-Banger 4-Speed-Man. White
Was the diff kind of a cylinder shape? (Instead of the tapered, like the Trac-Loc units).
An '84 may have a Torsen in it. I know the diff in my '84 XR-7 was.
83 TC "Clone"
85 Marquis LTS
86 LTD Wagon
I can't remember. I will try to see if I can get a pic. Traveling.
Just looked at some 7.5 units, definitely not it. Looks like the auburn stuff.
Last edited by emerygt350; 06-05-2023 at 05:32 PM.
1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
Comp cams XE254H, hypereutectic pistons
Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.
Maybe it was the Auburn stuff the earlier cars had. It's been a minute since I had that all apart. (and it's gone now)
I know it wasn't a Trac-Lok unit.
83 TC "Clone"
85 Marquis LTS
86 LTD Wagon
84 and earlier had "Auburn-like" Traction-Lok differentials.
Axle Tag Decoder
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FEP Registries: Black Magic & Crimson Cat / Cobra / Dominator / G.T.350 / LTD LX/Police & Marquis LTS / M81 / Pace Car / Predator / Saleen / Turbo GT & Turbo RS / Twister II
Wanted (Dead or Alive): VINs, door tags, buck tags, build sheets, window stickers, owner cards, transmission tags, axle tags
Any idea how to get parts? Will auburn parts work?
1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
Comp cams XE254H, hypereutectic pistons
Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.
If you can find NOS parts for a diff that hasn't been in use for a few decades, I wish you luck. Otherwise, used parts for that style, replace the diff with the newer style of T-L, or replace with an 8.8 rear. I did the last one when mine blew apart in my 83 GT. I understand if you want to keep the 7.5 in your 84, so find a better diff from an 85+ C/M or other models that used that style and had T-L.
Axle Tag Decoder
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FEP Registries: Black Magic & Crimson Cat / Cobra / Dominator / G.T.350 / LTD LX/Police & Marquis LTS / M81 / Pace Car / Predator / Saleen / Turbo GT & Turbo RS / Twister II
Wanted (Dead or Alive): VINs, door tags, buck tags, build sheets, window stickers, owner cards, transmission tags, axle tags
I have the original 7.5 out of my 84 SVO if that helps. No idea what is actually inside the housing as I have never taken it apart. Let me know if that may help you out to get yours fixed. Good luck!
Trey
"I Don't build it hoping for your approval! I built it because it meets mine!"
"I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."
Mustangs Past: Too many to remember!
Current Mustangs:
1969 Mach 1
1979 Pace Car now 5.0/5 speed
1982 GT Stalled RestoModification
1984 SVO Still Waiting Restoration
1986 GT Under going Wide Body Conversion Currently
Current Capris:
1981 Capri Roller
1981 Capri Black Magic Roller Basket Case
1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
1984 Capri RS T-top Roller
1983-84 Gloy Racing Trans Am/IMSA Body Parts
At this point I think my only hope is to find a used unit and steal the parts I need. Trying to avoid pulling it all apart. I can just slide the new plates and spiders into the existing carrier. Just hard to know if the used parts I would buy are the same as what is in it.
1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
Comp cams XE254H, hypereutectic pistons
Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.
They used the 7.5 for a long time. You should be able to find one in a V6 Mustang or a Ranger at the junkyard. Just grab the carrier, you probably want new gears anyway. Finding one with trac loc, I don't know how rare or plentiful they are.
My early '85 GT has the Auburn style. Pretty sure it's the original unit too.
'85 GT
Not familiar with any Mustangs with factory Auburn limited slips, but if they are like the aftermarket Auburns, they are a cone style, with no clutch plates inside. If so, those are not rebuildable, as they use grooved tapered cones, that can eventually wear to the point where they essentially "eat themselves up". The cones as well as the case wears, and once they get to that point, they are scrap. To be honest, I would just swap in a 8.8 from a 86-93 Mustang. Much stronger with a far better availability of replacement parts.
1978 Fairmont 2 door sedan, 428CJ 4speed. 9.972ET@132.54mph. 1.29 60 foot
Replaced the FE big block with my 331/4 speed in my Fairmont, best 10.24ET @128 MPH.
1985 Mustang LX hatchback NHRA Stock Eliminator 302 4 speed best in legal trim 12.31@107 mph, but has gone 11.42@115 with aftermarket intake, carb, and iron Windsor Jr. heads.New for 2012! 331 cube SB Ford, AFR 185 heads, solid flat tappet cam, pump gas; 10.296ET@128.71 mph, 1.37 60 foot.
1979 Zephyr Z7, all original 302 auto, 2nd owner.
Yeah, we are considering all options. But I do want to keep the price down.
1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
Comp cams XE254H, hypereutectic pistons
Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.
Best advice I have seen on here yet......Originally Posted by mcfairmont
May not be/probably not an actual Auburn differential. Reason why people, me included, say it is "like" one is because the pre-load spring assembly with coil springs between two plates, instead of the pre-load S-spring that the 8.8" diffs have.
Axle Tag Decoder
Buck Tag Decoder
Door Tag Decoder
Owner Card Decoder
Transmission Tag Decoder
VIN Decoder
FEP Registries: Black Magic & Crimson Cat / Cobra / Dominator / G.T.350 / LTD LX/Police & Marquis LTS / M81 / Pace Car / Predator / Saleen / Turbo GT & Turbo RS / Twister II
Wanted (Dead or Alive): VINs, door tags, buck tags, build sheets, window stickers, owner cards, transmission tags, axle tags
The metal ( from the cone clutch wear ) collects and floats around in your differential fluid....Not what I would want lubing my gears...
Here is what I replaced my 7.5 with, but I am spending my childrens inheritance....
Ended up getting a whole new carrier with a clutch style limited slip.
1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
Comp cams XE254H, hypereutectic pistons
Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.
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