8" backlash question - MustangForums.com

Go Back   MustangForums.com > Ford Mustang Tech > Classic Mustangs (Tech)

Classic Mustangs (Tech) Technical discussions about the Mustangs of yester-year.

8" backlash question

Thread Tools Search this Thread
Old 06-11-2013, 12:52 PM   #1
4th Gear Member
groho's Avatar
Join Date: Oct 2005
Posts: 1,153
Default 8" backlash question

Let me pose my rearend question in a different manner in the hopes of getting some feedback. I purchased a new center section, with new tracloc, and ring/pinion and dropped it in my coupe just before I started my restoration. I checked the lapping they had done and the pinion was centered on the ring, as should be. I dropped it in, broke it in, all was good. Noticed after roughly 200-300 miles I had a subtle whine, and eventually a clunk coming from the rear. The car has sat being restored for the last 2 yrs or so, no miles. Was under the car resetting driveline angle (dropped suspension) last week and turned the driveline by hand, noticed more play than the expected .0008-12 backlash. So...... I suspect the extra play has come from the bearings seating, and being broken in. I'd like to pull the center section and recheck backlash, to insure nothing is damaged. I have the dial indicators and tools to do this work, but have never worked on a rear end. Doesn't seem difficult, and don't intend to break the unit down, just double check side load followed by another lapping to check ring/pinion mesh. Have any of you done this with positive results?
groho is offline   Reply With Quote
Old 06-11-2013, 03:29 PM   #2
6th Gear Member
Join Date: Apr 2007
Vehicle: 67 Mustang Coupe
Location: California
Posts: 10,453

Prolly the pinion nut coming loose. Or not properly tightening to begin with. If a bearing collar or race wasn't completely seated, once everything settles you lose preload on the pinion bearings and the pinion gear ***** to an angle under load.
Who cares how much horsepower it has, all that matters is how fast it goes!

Untested 331, lots of suspension, chewing up corners.
67mustang302 is offline   Reply With Quote
Old 06-12-2013, 11:28 AM   #3
5th Gear Member
boogerschnot's Avatar
Join Date: Feb 2007
Vehicle: 69 Grande' Coupe / 67 A Fastback
Location: San Diego, CA
Posts: 2,638

To answer the question. Yes, pull it out and take a look. You could possibly re-torque the pinion nut if it has a shim set and not a crush collar. If you find that it was wearing in a bad way, then take it in. Or try it yourself. I learned a lot by doing my own rear end work, especially how to lock up the rear by over torquing the pinion pre-load.

I took my rear in to be set up the second time around and then realized I shouldnt have skimped on my gear selection, cheap gears meant whining gears for me.

Take a look at it.
69 Grande' 351W/AOD Performer Intake/Cam, 670 Holley Avenger, Hooker Headers, 3.70 9"TracLoc
67 Fastback A Code: 64k Miles, all original project for the wife.

boogerschnot is offline   Reply With Quote


Similar Threads
Thread Thread Starter Forum Replies Last Post
Intake manifold replacement Dokilar 4.6L (1996-2004 Modular) Mustang 15 10-16-2015 09:13 PM
Win $1500 Worth of RTR Parts - AmericanMuscle AMAlexLazarus AmericanMuscle.com 3 10-02-2015 09:06 AM
October Sale - AmericanMuscle AMAlexLazarus AmericanMuscle.com 0 10-01-2015 11:29 AM
Hot Lap: 2015 Roush RS3 Test + Build a Supercharger! - AmericanMuscle.com AMAlexLazarus AmericanMuscle.com 0 10-01-2015 10:21 AM
Hello, new user with an older Mustang and a question treesloth New Member Area 4 09-28-2015 08:03 AM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump


All times are GMT -5. The time now is 10:21 PM.

This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company