Synthetic oil kills trac-loc?

Dean85GT

New Member

Nov 27, 2004

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Thorold, Ontario, Canada

Mar 9, 2006

#1

• Mar 9, 2006

• #1

I picked up some Castrol Syntec 75w90 full synthetic for my rear end....One of my friends told me to return it for semi-synthetic because a full synthetic wrecks the trac-loc? Does any one have any experience or insight?
thanks

 

Mavrick

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Aug 29, 2002

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Collingwood, ON

Mar 9, 2006

#2

• Mar 9, 2006

• #2

Many people run synthetic in the rear end, and i've never heard such a thing.

 

RandyStinchcomb

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May 25, 2005

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Randallstown, Md

Mar 9, 2006

#3

• Mar 9, 2006

• #3

total bull****, most new Ford cars and truck come from the factory wth full synthetic gear oil in the rear, both posi and non-posi trac rears.

 

crazypete

All my crevices are greased.

Oct 22, 2004

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Arlington, MA

Mar 9, 2006

#4

• Mar 9, 2006

• #4

I rebuilt my trackloc and use mobil1 75w-90 with no friction modifier and the tracloc works like a champ! Your friend is wrong.

 

8

8950HO

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Mar 31, 2005

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Mar 9, 2006

#5

• Mar 9, 2006

• #5

Most of the good synthetic gear oils like Mobil 1 already contain a limited slip/trac-loc additive package so you don`t need the Ford friction modifier.

I`ve used Mobil 1 75W-90 since the early 90`s with no problem.

 

RacEoHolic330

I like to dress like a pretty girl

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Mar 4, 2003

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Allentown, PA

Mar 9, 2006

#6

• Mar 9, 2006

• #6

It depends on the type of diff and what kind of clutch packs are used. When I bought my Eaton posi, there was a huge orange tag on it that said NOT to use synthetic gear oil.

 

Dean85GT

New Member

Nov 27, 2004

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Thorold, Ontario, Canada

Mar 9, 2006

#7

• Mar 9, 2006

• #7

I just have a stock rear diff....The oil I have is castol syntec 75w90...I cant find the reciept so I cant return it. Thats why I was wondering.

 

T

townethug

20+ Year Stangneter

May 17, 2004

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Mar 9, 2006

#8

• Mar 9, 2006

• #8

When i had my 3.73's put in i rebuilt the trac-lok also. Been using synthetic since the rebuild about 8 months ago. No problems yet.

 

HISSIN50

"How long does it take to get help in here?

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Nov 29, 1999

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Mar 9, 2006

#9

• Mar 9, 2006

• #9

How about this thinking: The synthetic arguably is slicker than dino oil right. What is friction modifier? It lowers the coefficient of friction between the clutches, making them bite less hard. Seems that synthetic is helping to achieve the same goal.

How I do synthetic rear end changes: Depending upon the type of fluid used, one might not need Ford modifier. I would swap the fluid in and if the rear chatters, then add the modifier alone. It's easy to add modifier but hard to remove just the modifier.

As you can tell, I dont buy that original argument, as most in here dont.

 

8

8950HO

New Member

Mar 31, 2005

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Mar 9, 2006

#10

• Mar 9, 2006

• #10

e-mail Castrol and ask them if their 75W-90 Syntec gear oil is compatible with your traction-loc rear end without having to add any friction modifier.

I`ll guess here that they say it is,and doesn`t require the modifier.

 

Grn92LX

Fidanza Man!

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Jan 14, 2001

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New York

Mar 9, 2006

#11

• Mar 9, 2006

• #11

Some posi units, the manufacturer recommends not using synthetic. I don't think castrol syntec is a true synthetic anyway.

You can run synthetic in the stock posi no problems.

 

tmoss

Gettin Wired

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Jun 28, 2001

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Saint Louis, MO

Mar 10, 2006

#12

• Mar 10, 2006

• #12

HISSIN50 said:

How about this thinking: The synthetic arguably is slicker than dino oil right. What is friction modifier? It lowers the coefficient of friction between the clutches, making them bite less hard. Seems that synthetic is helping to achieve the same goal.

Click to expand...

Thee is the crux of the arguement right there.......