Ormachek

iTrader: (1)

OK so here's the deal...I have an LSD rear end out of an 82, but i need it to work with an 83 style driveshaft with the different connecting flange to the diff....can i swap out the flange somehow on the rear end? or do i need a whole 83-85 rear end? just so you know, changing the flange on the driveshaft isn't really an option for me here so....advice?

flycasta

iTrader: (3)

So long as the axles size is the same yes you can change the pinnion flange but it may pay to get a diff rebuilder to do it and check the backlash once it's done because removing the old 1 and replacing it with another will change things ever so slightly.

I thought the pinnion flange only changed when the axle size change from 24 to 26 spline and also the whell stud pattern changed.

rotor vs. piston

Looking at the parts list and having had a 84 -SE with the "small flange" it's supposed to be a direct swap.

Honestly the best answer is just to find the correct shaft for the flange.

Quicker10u

Yea, find the correct driveshaft for the flange...That would be easiest..

speedturn

iTrader: (1)

I have changed out the flanges. Go ahead and change the seal while you have the old flange off.

Whizbang

yeah my GSLSE has the 81 flange with the rebuildable SA driveshaft so i know if works.

Hades12

You can just change the flange, It is one bit nut and then tap it off or use a puller, they say to change the crush washer when you do it.

Rx-7Doctor

iTrader: (13)

If you have a small flange on your diff it has been changed. The small flange was used from 79-83 1/2 models.


Ormachek, It's easier just to get a different driveshaft if you have the larger diff flange. The diff is a bolt in. If you change the flange and have to have the crush washer replaced then the backlash has to be rest on the diff. It would be cheaper to get a driveshaft off a member in your area. But verify that your 83 diff is the large one first. The bolt centers on the diff would be 2.5 inches center to center if it is the larger flange.

Flycasta. The flange has nothing to due with the axle or the bolt pattern. The axles changed in 84 with the different spline and the larger axle bearings. So if you were trying to use 84 axles in a 83 or earlier housing they would not fit. And the only different bolt pattern is on the Se's in 84-85.

peejay

I have seen several rearends destroyed by people who changed flanges incorrectly.

So, the answer is, if you have to ask, then no, you can't do it.

Rx7carl

I'm kinda with Pete on this one. However many people have sucessfully done it. Can't say how long those rears lasted. I have set a few of them up the right way, and some special tooling is required (look in the FSM for the procedure). Hades, its not a washer, its a crush spacer. Thats where the big sticking point is. You need to use a new spacer as its a one time crush thing. It crushes down when you torque the flange nut. This ensures the correct preload on the pinion bearings. Like I said, Ive heard of many people not doing this. Maybe they got lucky? Maybe they sold/wrecked the car before it blew up on them, I dunno. I only know that your rear wont last if the preload isint right.

A small tidbit of info on the subject. Always keep the flat spacer with the housing. I got this from Mazdamotorsports. Apparently the pinions are all identical in specs. The variances that necessitate the need for the flat spacer come from variences in the housing tolerances during mfg/machining. So if you change your R&P, keep the flat spacer that came on the housing.

t_g_farrell

iTrader: (1)

Now this is what this forum is all about. Its small pieces of wisdom like this that make this board great.

Whizbang

yeah i would have never guess that...

rotor vs. piston

That was my point...

flycasta

iTrader: (3)

Thats kinda what I was trying to say. The only reason the pinnion flange would need to be changed is if he has been given a large axle carrier as all of the pinnion flanges up to 83-1/2 were the small type flanges, well they were over here anyway, and after that they were the larger flange, which I thought was also when the different wheel stud pattern was introduced.

trochoid

iTrader: (6)

Fyi, make sure you get the nuts/bolts with whichever flange you use. They are different between the big/small flanges. These are also the strongest bolts in the entire car. Don't remember offhand if they are 10 or 12 grade. If the installed flange has nuts, they need to be rated too. You won't find either at the local hardware store, McMaster-Carr perhaps or a large specialty fastener company.