IRS gear swap question

[ladenblowfish]

Hey guys, I planning to do a gear swap in my 93 lincoln mark 8. I've done gear swaps with straight axle rear ends, but never with an IRS. Is it about the same or is it more difficult? Also, will a new traction lock unit work as long as its for 28 spline axles? Or does it have to be for a IRS? Is there a difference? Thanks!

 

[NateRW21]

IRS is exactly the same. Only difference is instead of axle shafts, you have flanges. 28 splind traclok will do the trick.

There are only two types of 8.8 diffs... 31 spline and 28 spline. Other than that, the insides are all the same; and if you can resource the parts, spline count can be changed as well.

 

[mrzeee]

Also unless the "trac-loc" is new, and you must check on the build date, the axles will NOT LOCK into the side gears if the used unit was from a solid axle car. The newer trac-locs are made to accept the irs or solid shafts with an extra provision cut into the gears. A new trac loc is available from ford racing for $215. list and LVC cost is $192. plus frt. seals and brgs are available as well.
max

 

[ladenblowfish]

Great! Thanks! What about the gear ratio? I was planning on going with 3.73s.

 

[brentalan]

If you want to save yourself some trouble you can buy a ford racing 3.73 pumpkin all built from Mr. Zeeeeeeee

then all you have to do is swap them.

 

[98LSC32V]

I believe the Ford Racing 3.73 center section is no longer available.

 

[mrzeee]

Brent thank you!! however those have not been available for a few years now...that would have been the ticket though.

max

 

[Psychostang]

If you buy new side gears seperately, will they have the appropriate groove cut in them?

 

[kustomizingkid]

What year did the track lock carriers change?

 

[brentalan]

Dang, that's too bad. It was great when I did mine. Sorry to hear that they don't have them anymore.

Brent thank you!! however those have not been available for a few years now...that would have been the ticket though.

max

 

[98LSC32V]

3.73's aren't enough for these cars anyways. 3.90 minimum.

 

[ladenblowfish]

i was thinking 3.73s or 4.10s. i still want to get decent mpg.

 

[mrzeee]

The ford racing M-4209-G410M are $225.00 and LVC is $198.00. I do sell these mostly to mark 8 guys. The 373's are $178.80 LVC cost.
Max

 

[Psychostang]

So Max, do the replacement axle and spider gears for the t-lock come with the appropriate groove cut in them. I have the 28 spline t-lock out of my 91GT I was planning on using in the mark.

 

[Markviiiedrea]

I got a used (apox 3-4000 miles) 4.10:1 diff with new posi bearings and seals for sale, I just can get it out till spring.

 

[kustomizingkid]

How much? I'm fairly close to you.

 

[mrzeee]

Psych

The newer ford kits are for the irs, or for the solids. Ford does not make a set for both. There is a complete for both from ford racing. The irs trac loc set of gears would be 97.85 LVC cost and you would still have an old carrier, clutches(47.00) and brgs(90.00). for the difference of 100.00 you would have all new stuff.

 

[NateRW21]

Yeah.. I believe what MrZeee is trying to tell you would be... traklocs are cheap; it doesn't really pay to rebuild them when you also need new side gears. Just buy a new unit with bearings already pressed.

Or, if you plan on real horsy power... go pick up yourself an Auburn Elected; it's a limited slip that can be electrically locked. Or the Eaton E-locker (I have this in my truck); it's open and can be electrically locked.