|Latest update: 2/4/12
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What is presented here?
I have measured a few axles at my local junk yard to get an idea of what axle could be used to replace my present 1983 RX-7 GSL rear end. The RX-7 axle is 57.250" (+/- 1/8" or so) when measured from one WMS (Wheel Mounting Surface) to the other WMS.
This top view drawing shows where my measurements were taken from.Axles I've measured:
(Click on the drawing for a larger, clearer view.)
Axle measured WMS-
Ratio LSD or open
My '83 RX-7 GSL 7" 57.250 28.625 27.375 1.250 10 4 8 3.933 clutch plate LSD '86 Ranger 7.5" 56.500 30.500 26.000 1.875 10 4 14 4.10 open '93 Ranger 7.5" 58.250 29.500 28.750 0.750 ? 6 ? 3.45 open '86 Mustang 7.5" 59.500 30.500 29.000 1.500 ? ? ? LocostUSA.com post '92 Mustang 7.5" 59.125 30.500 29.125 1.375 9.75? 4 ? 3.73 open '80 Volvo 240 7.12" 54.00? 26? 28? 2? 10.5 3? 9 3.91 Torsen LSD '91 S-10 pick up 7.6" 54.500 27.562 26.687 0.875 12.0 Yoke 12 see Edit, 2/4/12 below
- Items with "?" were either not measured or the measurement was difficult to take and may not be correct.
- Axles will be added as I measure them. I will be happy to add anyones similar measurements on other 7" or 7-1/2" rear axles to the list.
- The list right now only has 7", 7.5" & 7.6" diameter ring gears. The 8" and up axles are way too big for my use.
- Most Ford axles I've measured have two shock mount brackets that are ~42" apart on the rear of the axle. This is the same measurements used in the "book" for the link brackets. It appears that one of the stock brackets could be used as the pan hard mount.
- It looks like the '79-'92 Ranger axle would fit a book chassis with no width modifications except for the pinion offset.
- The '79-'93 Mustang axle is 3" wider than a the Ranger and should fit a + chassis as is.
- Ford standard gear ratios for the '79-'93 Mustang 7.5" axles are 3.08, 3.27, 3.45, 3.73, 4.10.
- The Ranger has the same ratios except that the 3.27:1 ratio is not used.
- I've read on the web that only the ring, pinion and spiders gears of the Mustang and Ranger axles are interchangeable. At the same time I've read that the LSD from a Mustang will go into a Ranger. So don't quote me either way, since I haven't tried to change them.
- Wikipedia says that the '86+ Ranger 4 wheel drive 7.5" diameter axle has LSD. The axle codes indicate that the following ratios were offered; 3.45, 3.73 and 4.10.
- The Volvo rear end is almost too narrow. It's the narrowest one I've found in a junk yard.
- If you find '79-'92 Rangers with the left side axles missing here's why. The left side '79-'92 Ranger axles are the same length as the left and right side '79-'93 Mustang 28 spline axles. People who are converting a Mustang rear axle from 4 bolt rims to 5 bolt rims will use two the left side Ranger axles (5 lug bolts) to replace their Mustang 4 bolt axles.
- PLEASE do your own research for facts on any of the axles listed here since a lot of us got burned on the mythical 7.5" Courier carrier that would fit into a 7" Miata (and by reference, RX-7) axle housing. I'd like to see someone cram a 7.5" diameter carrier into the opening made for a 7" carrier. It's hard enough to get the 7" carrier into the 7" housing.
[Edit, 8/20/11] Update on internal parts interchange between Ranger and Mustang axles.
I called the Ford Racing website help number and was told that 1979-1993 Mustang 7.5" rear end gears and Trac-Loc will fit into a 1979-1992 Ranger 7.5" axle housing. I caution you to call them yourselves or do some additional research to make sure.
[Edit, 2/4/12] Additional information about the S-10 rear ends.
I've measured a neighbors 1991 S-10 two wheel drive p/u 7.6" axle and it is apparently 54.5" WMS-WMS with the brake drums mounted. I can't guaranty my measurements since the axle was still in the truck and had the wheels mounted. 54.5" is what other people are quoting on the web.
This axle looks very promising since gears from the 1999-2002 F-body Firebird and Camaros are said to fit. The normal S-10 ratios are 3.08, 3.23, and 3.42. The 3.23 ratio is the normal ratio for a manual transmission. The other two ratios are for the automatic. Three different 7.6" (insert your favorite name here) LSD units are used on the F-body Firebird/Camaro axles which will fit into the housing. From what I've found so far the S-10 axles of interest were made from 1985 to 1993 (see "Wikipedia S-10").
Start your search for S-10 info here. I've found an article here that gives the pinion offset of the 7.6" S-10 axle as 0.875". The article is mainly concerned with installing a 7.5" S-10 axle into a Vega etc but it also has the dimensions of the 1988-1993 7.625" S-10 axles. The article shows the WMS-WMS to be 54.25" without the drum brakes installed.