Rear end ratio question January 08, 2009, 02:59:24 PM In 87 and 88 were the rear end ratios in the 3.8l and the 5.0l engines the same? If so what were they?I was under the impression they are the same, but was just reading a post by another member who says they aren't. Quote Selected
Rear end ratio question Reply #1 – January 08, 2009, 03:38:15 PM Some had 3.08 gears, some had 2.73. The V6, I believe, had 3.08 as standard equipment, since it needed shorter gears to have decent acceleration. 2.73 was the standard gear in 5.0 models, with 3.08 being optional (mine had 2.73's until I swapped the 3.55 TC rear in). 3.27's were available on the V6 cars as well, but I don't know if they were available in 87-88.If you've got the original rear you can see what gears you have by looking at the door tag and comparing the rear axle code to the chart on Eric's Coolcats Quote Selected
Rear end ratio question Reply #2 – January 08, 2009, 04:30:32 PM The 1988 XR7 had 3.08 gears (locking) as standard with the 8.8" rear end.The 1987-88 Turbo Coupes had 3.73 (automatic) and 3.55 (manual) gears with their 8.8" rear end.I'm pretty sure all other base V6 and V8 models had the standard 2.73 open rear end. If one opted for the heavy duty suspension, then you'd get a 3.08 7.5" rear axle...that should have been locking, but may not have been. At some point in the mid-1980's Ford eliminated the towing package (1985-86ish IIRC) and just offered the heavy duty suspension, which was essentially the V8 Sport suspension without the larger battery upgrade, larger alternator, etc.I'll check my books when I get home. Quote Selected
Rear end ratio question Reply #3 – January 08, 2009, 05:19:22 PM Thanks Eric. What constitutes a heavy duty supension? I know my parts car has quadra shocks, it was an elderly womens car and then an adult male, so its not like someone added them for handling etc.. Quote Selected
Rear end ratio question Reply #4 – January 08, 2009, 05:29:20 PM the 88 v6 rear i have is a 3.27 trak lok, my 84 and 86 v6 have been 2.73 open as well as my 86 5.0 is a 2.73 open. Quote Selected
Rear end ratio question Reply #5 – January 08, 2009, 06:27:05 PM Quote from: EricCoolCats;250815If one opted for the heavy duty suspension, then you'd get a 3.08 7.5" rear axle...that should have been locking, but may not have been.My '88 5.0 had the heavy duty suspension (rear sway bar, 10" drums, but no quad shocks) but was a 2.73 open rear. The dearly departed '87 Sport had a 3.08 locking diff, and had quad shocks, but, of course, it was a Sport. When redoing the rear end bearings I installed a set of 3.27 gears into it out of an 85-86 V6 T-Bird, and I think back then somebody told me (Shawn, perhaps?) that 3.27 was the standard rear gear in four-eye V6 'Birds and Cougars. Quote Selected
Rear end ratio question Reply #6 – January 08, 2009, 07:02:13 PM I don't have the 1983 facts book pages for the rear end gear ratios, but I do have 1984-86 for the U.S. (sorry, no Canadian figures):19843.8 V6 - C5 trans - 2.73* in 49 states + California5.0 V8 - AOD trans - 3.08* in 49 states, high altitude and California2.3 I4 - C3 trans - 3.45 Traction-Lok in 49 states, high altitude and California2.3 I4 - T5 trans - 3.45 Traction-Lok in 49 states, high altitude and California*Traction-Lok available as an option (order code 45A, not available with TRX wheels and tires).Suspension, Heavy Duty (order code 662)Includes heavy duty shock absorbers, rear springs, stabilizer bar. Not available on XR7. Not available with P205/70HR14 BSW tires or 220/55R390 TR-type BSW tires.Trailer Towing Package, Medium Duty (order code 668)Designed for 3,500-pound maximum trailer weight and 500-pound maximum tongue weight. Includes heavy duty batter (54-amp/hr), 60-amp alternator, upgraded cooling system, heavy duty suspension, 5.5"x14" heavy duty wheels, automatic transmission auxiliary oil cooler, wiring harness for trailer towing†, power steering auxiliary oil cooler, luxury wheel covers, heavy duty flasher and relays, conventional spare tire. Requires an aftermarket Class II load equalizer hitch, 5.0L engine and automatic overdrive transmission and P205/70R14 WSW or BSW tires.†This feature is not believed to have made it to production, as I have cancellation papers for it.=================================19853.8 V6 - C5 trans - 2.73** in 49 states + California5.0 V8 - AOD trans - 2.73** in 49 states, high altitude and California; 3.08 available in CA with towing package2.3 I4 - C3 trans - 3.45 Traction-Lok in 49 states, high altitude and California2.3 I4 - T5 trans - 3.45 Traction-Lok in 49 states, high altitude and California**Traction-Lok available as an option (order code 45A, late availability with 5.0 engine).Suspension, Heavy Duty (order code 662)Includes heavy duty shock absorbers, rear springs, stabilizer bar. Included with medium-duty trailer towing package. Not available on XR7. Requires P215/70R14 WSW tires. Late availability with 5.0 engine.Trailer Towing Package, Medium Duty (order code 668)Designed for 3,500-pound maximum trailer weight and 500-pound maximum tongue weight. Includes heavy duty batter (54-amp/hr), upgraded cooling system, heavy duty suspension, 5.5"x14" heavy duty wheels, automatic transmission auxiliary oil cooler, power steering auxiliary oil cooler, conventional spare tire. Requires an aftermarket Class II load equalizer hitch, 5.0L engine and automatic overdrive transmission and P215/70R14 WSW tires. Not available on XR7.=================================19863.8 V6 - C5 trans - 2.73 in 49 states + California3.8 V6 - AOD trans - 3.27 in 49 states + California; 3.45 high altitude5.0 V8 - AOD trans - 2.73*** in 49 states, high altitude and California2.3 I4 - C3 trans - 3.45 Traction-Lok in 49 states, high altitude and California2.3 I4 - T5 trans - 3.45 Traction-Lok in 49 states, high altitude and California***Traction-Lok available as an option (order code 45A, 5.0 engine only).No heavy-duty suspension or trailer package options were listed in my book for 1986.=================================A Traction-Lok equipped XR7 would have had quad shocks. It's possible that Traction-Lok optioned 5.0 and 3.8 cars may have had quad shocks from 1983-86, but reports have been very scarce about them.I haven't found the 1987-88 spec sheets--as in, I don't have them. They're tough to find.Of course, these are the official Ford books, but that doesn't mean that they're 100% correct. YMMV. Quote Selected
Rear end ratio question Reply #7 – January 08, 2009, 07:43:15 PM My 87 had a tow pack on it, 273 no lock on it.My door tag didn't lie either. Quote Selected
Rear end ratio question Reply #8 – January 10, 2009, 03:49:27 PM ^ same for the 87 20th Quote Selected
Rear end ratio question Reply #9 – May 12, 2009, 04:57:17 PM What part of the door tag designates the rear end? And does locking mean "posi"? Quote Selected
Rear end ratio question Reply #10 – May 12, 2009, 05:13:19 PM Quote from: jpc647;271888...And does locking mean "posi"?"Posi" is short for Positraction which is the Chevy term/brand for what Ford calls Traction-Lok (or Trac Lock). Both are limited slip differentials. Quote Selected
Rear end ratio question Reply #11 – May 12, 2009, 06:10:06 PM Quote from: jpc647;271888What part of the door tag designates the rear end? And does locking mean "posi"?The part that says "AX" along the bottom of the sticker. You cna see it in my door tag, posted below. The "AX" is actually worn off, but you can see the code "8" (meaning 2.73 open diff in my car) next to the code TKKDD at the bottom right side of the sticker. Quote Selected
Rear end ratio question Reply #12 – May 13, 2009, 03:30:40 PM Well it appears the past car had the optional heavy duty suspension, who knows why it was a elderly womens car.Anyone know if the quad shocks are still availible anywhere? Quote Selected
Rear end ratio question Reply #13 – May 13, 2009, 03:50:54 PM Are you just going by the letters "HD" on the door tag as shown on mine? That's the interior trim code (HD must mean "Base porno red"), not the suspension code.I'd imagine quad shocks are available but you'd have to buy 'em for a Mustang. Quote Selected
Rear end ratio question Reply #14 – May 13, 2009, 04:25:14 PM So then my 85 XR7 has 3.45 Trac-Lok? I was always under the impression that automatic XR7's with the turbo four had 3.73's Quote Selected
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