This is topic 3.90's...who's got 'em...how do you like 'em in forum Tech Talk at Northern California Ford Owners  .


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Posted by unfknblvbl89 (Member # 1522) on :
 
In the first part of Feb. I am looking at getting gears. I am thinkin either 3.73's or 3.90. Everyone says 3.73' are good and 4.10's may be a little steep for an everyday driver.

This is what I was thinkin meet in the middle with the 3.90's, eaton posi unit and new 31 spline axles.

Any input on the gears or my thought will be appreciated. Thanks in advance.
 

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Posted by 91sleeper (Member # 779) on :
 
If 3.90's were out when I got gears thats what I wouldve put in my car. Motive makes them and I belive Chuck has them in his gt and hasnt had any problems that I know since the last timne I talked to him. Maybe he will drop a line.
 

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Posted by GR40coupe (Member # 698) on :
 
My boy has them in his car he likes them.
 

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Posted by unfknblvbl89 (Member # 1522) on :
 
Here is a question regarding differential's.

I understand what a posi unit is, but what is the difference posi and limited slip. Which is preferred in a daily driver.

Thanks
 

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Posted by 87 Saleen (Member # 1549) on :
 
posi woowoo
 

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Posted by 91sleeper (Member # 779) on :
 
Same thing just a differnt name. Posi Traction is the same thing as Track lock and Limted slip they are just all differnt names if I am correctly remembering.

Gm uses the term Posi Traction and Ford uses the term Track-Lock and/or Limited Slip.
 

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Posted by 2000BlackGT (Member # 283) on :
 

quote:

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Originally posted by 91sleeper:
If 3.90's were out when I got gears thats what I wouldve put in my car. Motive makes them and I belive Chuck has them in his gt and hasnt had any problems that I know since the last timne I talked to him. Maybe he will drop a line.

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quote:

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Originally posted by unfknblvbl89:
Here is a question regarding differential's.

I understand what a posi unit is, but what is the difference posi and limited slip. Which is preferred in a daily driver.

Thanks

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I am almost positive that the two are different. Limited slip means that both wheels will turn, but the other one gradually goes, it doesnt pick up immediately. True posi traction means that both wheels spin at all times. Not sure on this though...
 

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Posted by flatacid (Member # 878) on :
 
nope. posi and limited are the same. true posi would be a spool.
 

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Posted by flatacid (Member # 878) on :
 
oh yea. i have 4.10's. if you drive alot on the freeway, i would go 3.73's. if not, go 4.10's. but whatever you get, if you ever decide to go higher (numerically lower), then your gonna be dissapointed. im gonna be going to 3.55's cause of the new engine (long way away). i know im gonna be sad to see the 4.10's go.
 

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Posted by UST 635 (Member # 1708) on :
 
posi and trac loc are both brand names for "limited slip" like jared said posi is only gm and tracloc is only ford. When you hear a ford guy say he's got posi, he's also not very smart.

A locker never slips under load but will allow you to turn corners without the tires barking.

A full spool or mini spool will never let the axels turn seperatly.

I have 3.89s and with 28" inch tall tires and a .67 overdrive i cruise at 90 mph at about 2,700 rpm.
 

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Posted by Chosen1 (Member # 1906) on :
 
i have 3.89's as well in my fastback, and 373 in the cobra. i like the 3.89's a lot.
 

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