gears and trac loc

87TTOPGT420

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is the $300 plus im about to drop on 3.73's and a trac loc really worth it...?? Regardless im doing a trac loc, im tired of the 1 tire fire my car currently does ....but am i really gonna feel a difference in the butt dynometer vs the 3.08's now...or am i gonna have further trouble getting any traction?
 
I went from 3.27 and peg leg to a TL and 3.73s and most definatly can feel it! When Sapperfires car was faster then mine I would still destroy him through the first two gears as he struggled for traction. Good tires, TL and gears are grat on these cars to get their fat asses off the line rapidly. :)
 
I went from 3.27 and peg leg to a TL and 3.73s and most definatly can feel it! When Sapperfires car was faster then mine I would still destroy him through the first two gears as he struggled for traction. Good tires, TL and gears are grat on these cars to get their fat asses off the line rapidly. :)

word
 
As soon as my car runs right it will be 4.10's and a trac loc for me. I already have the trac loc...I just need to get the 4.10's and money for the install.

I was told by EVERYONE that got them that it was a BIG difference. As others like XLR have said 4.10's are what those with 3.07's should go with because it's a full gear change. People with 3.27's should go with 4.30's.

Many say 4.10's is too much but even Geno has them and has said his mileage is still great.

My opinion is go big or go home! ;)
 
I have 3.73 but I got them used for nothing. I know that before the trac-lok and gears, my car would spin off the line, now it just squats and takes off chirpping second at wot.
 
Trust me on this when I say it, get 4.10's. If I knew then what I know now I would have gone 4.30's.
 
It's been said that if you leave OD off, that will be a close indicator of what you will be at in OD with 4.10's. I'd be at almost 3000 RPM's at 80mph.

Marked you should have just gone with 4.56's and called it a day ;)
 
On my car, with 4.10's and 245/45-17" tires, 70 MPH = ~ 2700 RPM's and 80 MPH = ~ 3100 RPM's. Stock size wheels/tires will lower the RPM's a bit.
 
Okay this thread is making me want to start workin on the Mark again... lol!

I cannot wait to feel my car with 4.10's and a trac lok.... it's all sitting, waiting in the wings for when the car is inspected/re-titled and back to street action!
 
im doing this, but 3.73 is my gear of choice

what all do i need for the install....already got gears and trac loc with new bearings on the unit....i know i need a pinion seal and bearing...anything else? also what about shims???
 
The last gear set I bought (FMS) came with a shim set.

You may not need any if you are using a Ford sourced gear.

Crush sleeve?
 
im doing this, but 3.73 is my gear of choice

what all do i need for the install....already got gears and trac loc with new bearings on the unit....i know i need a pinion seal and bearing...anything else? also what about shims???

Ford Friction Modifier.
 
Ford Friction Modifier.

Unless you buy Royal Purple because it already has friction modifier in it. I called them personally and they verified that. It even said on the bottle with friction modifier. They told me it's unnecessary to use friction modifier with their product, and actually may hinder it's ability to work properly.
 
I have 3.73 and it made a huge difference in my car coming from 3.08. I would probably get 4.10s if I could do it over again but you will not be disappointed.
 
Friction modifier will cause the clutches in the trac lok to slip. IF you want full on "posi" style launches, leave out the modifier, or pack your trac lok with extra clutches if you insist on using the modifier.

As far as an install kit... go to a ford dealer or Jegs or whoever and buy the m-4210-c... that is the master install kit for an 8.8 rearend. It comes with axle bearings for a foxbody which you obviously wont need :lol: Everything else should be the same. And when I mean master kit... it comes with EVERYTHING. I would recommend rebuilding your trac lok if it's got some miles on it... otherwise you'll be back to your 1 tire fire soon... especially if you put the friction modifier in it.

I had my 3.73 put in my '94 GT without friction modifier (because I forgot it) and it "kicked posi" all the time... but my diff cover was leaking because I accidentally let a little oil seep out onto the sealer when I put it together, so when I took the cover off and re-sealed it, I used modifier... From then on, it will spin both tires until one hooks better than the other, then it will just spin 1.

Sucks at the drag strip when you are on drag radials trying to do a burnout in the box... then you take off out of the hole and the car kicks sideways because one of the tires is not as sticky.

But that is just my opinion and experience. With a car as heavy as the mark, I see it spinning one wheel a lot easier.

My friend Steve has an '89 LX running 11.30's on motor, after packing his 31sp. trac lok with extra carbon fiber clutches and still sometimes not spinning both tires evenly... he man'd up and bought a detroit locker, lol

Now that would be fun in a Mark, lol
 
even pennzoil 75w140 synthetic does not require friction modifier...all the friction modifier does is quiet down chatter

the unit itself is packed with new clutches and bearings already....but it would be nice to have the shims etc...just so i know the gears are meshed properly i hope to complete this before july 9th, before i goto the strip and make a couple passes for fun...
 
gonna goto St.Thomas, few guys from windsor mustang club are planning to got for T & T.....July 9th, we plan to leave windsor area at 5pm, get there at 7 and run till 10pm....i manna make a couple passes and my buddy with his '06 Monte Carlo SS wants to race my lincoln...but little does he know i plan to do the LSD and gears for that extra advantage to get me out of the hole...i mean our cars are fat pigs
 
Bit over 2hr drive each way to there for me :(
Cayuga is less than an hour for me. I wish I knew more guys that went there. I always seem to miss the T-Bird guys.
 

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