rearend change

[redcars]

What do you need to change when putting a 411 rear end axle from a 1978 Spider into a 1982 Spider that had a 390? The drives shaft?, pandhard rod?, or can you just change the axle assmbly and go. The reason I am asking is because mine stated to make noise and I put in new u-joints and center bearing. This did not make the noise go away even though these parts did need changing. I have the 78 axle and all the related parts just don't want to change more than I have to. I am planing on going to FUN this weekend and it will be about a 1,000 mile drive. I did more than thison a weekend without any problems. I could trailer it up there, but I would rather drive it. It looks like I will not be getting a lot of sleep this week.

[BEEK]

the 78, if it is the early type will have a 10/43 ratio, the 10/41 was from the 124 sedans, you can even find a 9/40 from some early sedans and ive seen it in coupes too but rare. the 78 on style rear came in 10/39 for the standard and a 3.58 for the auto

[BEEK]

but if changing the early to late style assembly, just use the correct panhard bar, keep the brake brackets with the proper assembly. and you will be good.

[redcars]

Beek thanks for the reply. Looks like my speedo will be running 5% slow now instead of 5% fast.

[vandor]

Beek thanks for the reply. Looks like my speedo will be running 5% slow now instead of 5% fast.

Actually it will be ~15% fast, as the car will be going 10% slower for the same engine speed.

The driveshaft length between the two is different by 10mm. The front slide yoke can usually accommodate this, but you need to loosen the center support bolts and let it 'find' its new position.

[Exit98]

The rear hard brake line is different between the two. I found out the hard way. If you get the whole assembly you'll be OK, but piecemeal you'll need the new one. Like Beek said the rear brake backing plates are different too. I switched driveshafts.

[spiderrey]

I know when you put a late rear end in an early car, you need to use the late drive shaft.

[redcars]

Well I put the 430 rear end in my 82 and all I had to change was the panhard rod. When I got done Thursday evening I took it for a test drive and the 430 rear end had a bad whine to it, so I decided I would not do the FUN event in Michigan this year. I am now going to put a 1st generation Mazda Rx7 rear end under it as they are tough and I like them.

[vandor]

Many years ago I measured an RX7 rear end and surprisingly it was several inches wider than the Spider. The RX7 seems to be about the same size car as the Spider, so I'm not sure why this is. So be sure to measure things before you start cutting

Also, the RX7 uses a Watts linkage instead of a panhard rod, so that has to be adapted. I assume you'd use a rear end from a GSL-SE, as it has discs in the back and a LSD.