• Mustang Forums
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech

8" ring/pinion setup question...

  • Thread starter Thread starter XStang302x
  • Start date Start date Aug 6, 2004

XStang302x

Founding Member
Nov 2, 2000
286
24
19
Marietta, GA
Aug 6, 2004
#1
  • Aug 6, 2004
  • #1
8" ring/pinion setup question *Pics Update*

Well my buddy got done putting in the gears for my rearend today. Took a little longer than he thought because he's a perfectionist hehe (I have no probs with that!). He currently has about 8-10 thousandths backlash on it. Now here's our question (1st time doing an 8" for him), he's tried every combination of pinion spacers to get that pattern in the middle of the gears. but it's still showing up more towards the toe side. I believe on the drive side, he has a nice little margin of space at the the top of the tooth. On the other side it appears to be flush with the top of the tooth. He's tried both extremes of spacers (and plenty of combinations within)and couldnt get it to where he wanted it.

He said he would be comfortable putting it in his car, was just bothered he couldnt get it where he wanted. He took some pics and is supposed to be emailing them to me sometime tonight just to get you guys/gals a better idea. Just not here yet hehe. When you look at the chart the picture represents it being incorrect backlash since it's rubbing more towards the toe...8-10 thousandths sound right to you guys?

I know it's hard to give a decent opinion without pics, hopefully my description was somewhat detailed enough to make somewhat of a judgement. Knowing all this, would you guys go ahead and toss it in?

UPDATE:

Here are the pics...what do ya'll think?











-Frank
 

XStang302x

Founding Member
Nov 2, 2000
286
24
19
Marietta, GA
Aug 7, 2004
#2
  • Aug 7, 2004
  • #2
Pics up...hope that helps!

-Frank
 

6Stang7

New Member
Jun 1, 2003
1,470
0
0
Livermore, CA
Aug 7, 2004
#3
  • Aug 7, 2004
  • #3
Well, .008-.010 is a good setting. Right now I have my 4.11's at about .007 because I wanted more of a strip setting. It sounds like your buddy hasn't assembled a Ford 8" before. You see the two main caps that hold the differential housing in place? Look on the side of them and you will see theses caps that have a bunch of holes around them. If you noticed, these, the main caps, and the carrier housing is threaded. To fine tune your backlash, you loosen the main caps a little, then tighten of the side caps while loosing the other to reduce backlash (or increase it depending on which one you loosen and which one you tighten). Once you have it where you want it (and I suggest that you use a gauge just to be sure) tighten the one you have been loosing back up and check again, then tighten the caps down. You're now good to go.
 

67bluestang

New Member
May 13, 2003
193
0
0
Tucson, Arizona
Aug 7, 2004
#4
  • Aug 7, 2004
  • #4
From what i can tell, the pinion looks a little to deep and shims need to be added if you want it out further. The pattern is close to what i usually ran in the race car. You want slightly heavier toe in high horsepower, good traction cars because the load will tend to pull the gears apart. Of course with an 8", i don't think you're looking at putting any serious horsepower to it. A heavy heel will be quieter. The backlash sounds about right.
 

XStang302x

Founding Member
Nov 2, 2000
286
24
19
Marietta, GA
Aug 7, 2004
#5
  • Aug 7, 2004
  • #5
So answer me this. With the way it's setup now....all I'm really looking at is extra noise? That doesnt bother me....hell more the better . Not going to shorten the life span or cause premature failure or anything will it? That's my main concern.

As far as the shims go...out of all the combinations of shims he tried, that was the most even one he could get close to the middle.

-Frank
 

67bluestang

New Member
May 13, 2003
193
0
0
Tucson, Arizona
Aug 8, 2004
#6
  • Aug 8, 2004
  • #6
Its hard to tell if there will much be noise or not. I'd give it a try and see how it goes. It might be a little more work later on if its too noisy, but if you're friend can't get them any closer, either use it or take it to someone else and see what they think. You'd think all gears would be the same, but i've had times when it took several hours to set up and other times, its done in an hour.
 

XStang302x

Founding Member
Nov 2, 2000
286
24
19
Marietta, GA
Aug 8, 2004
#7
  • Aug 8, 2004
  • #7
Went ahead and tossed em in. All seems to be well...course, only 1 mile on em hehehe. One thing is for sure...quite a jump from a 2.79 to 3.55 lol...weee!

-Frank
 
You must log in or register to reply here.

Similar threads

3
Eight inches is enough for me...
  • 351MooseStang
  • Nov 27, 2025
  • 1974 - 1978 Mustang II Talk & Tech
Replies
5
Views
497
1974 - 1978 Mustang II Talk & Tech Mar 2, 2026
Bullitt347
Place to Avoid: Jamison Auto Group in Gulfport, MS
  • D Durden
  • Oct 20, 2025
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • 2 3
Replies
45
Views
2K
1965 - 1973 Classic Mustangs -General/Talk- Feb 4, 2026
nickyb
Progress Thread Progress Thread- From6to8's 1994 Cobra Supercharger install
  • from6to8
  • Sep 25, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 20 21 22
Replies
420
Views
8K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 6, 2026
from6to8
M
Progress Thread mnky99 2001 V6 evap core, ac compressor, heater core replacement
  • mnky99
  • Sep 5, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
1
Views
423
1996 - 2004 SN95 Mustang -General/Talk- Sep 5, 2025
mnky99
M
Wheels-Tires LS mii swap and rear rim size/axle questions....
  • 78mIIman
  • Feb 2, 2025
  • 1974 - 1978 Mustang II Talk & Tech
Replies
6
Views
680
1974 - 1978 Mustang II Talk & Tech May 6, 2025
78 Mach1
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?