• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-

I'm having a new rearend built

  • Thread starter Thread starter Jason 302
  • Start date Start date Feb 7, 2012

Jason 302

10 Year Member
Aug 9, 2003
685
71
68
Newark, Ohio
Feb 7, 2012
#1
  • Feb 7, 2012
  • #1
So after recently installing some new rear control arms and battle boxes, I noticed I have a considerable amount of slop in my driveshaft without any movement from the axles. My pops seems to think a lot of it is coming from the axle splines, but I think it has too much backlash between the ring and pinion as well. I'll inspect it soon.

I had it re-built about 9 years ago by a local guy here. Stock 28 spline axles, stock re-built trac-lok, stock differential cover, and FRPP 3.73 gears. After many 6000rpm street slick launches and 9 years of street abuse, I think it is time for a overhaul.

I've had a spare rearend housing laying around for about 5-6 years. I tried setting it up around that time period, but could never get the tooth pattern that I wanted. Even after numerous pinion shim changes and backlash adjustments...I finally gave up lol.

Fast forward to today. I dropped the housing and parts off to a reputable shop here locally to have the following parts installed and setup.

- FRPP 4.10 gears (from 3.73's)
- Detroit TrueTrac differential (from Trac-Lok, interested to see how well it works at the strip)
- Solid pinion crush sleeve

I already had the axle bearings and seals installed as well as the pinion bearing races and seal.

When it gets home it will be receiving some Moser 31 spline axles and an aluminum differential cover.

Anybody have any guesses whether or not the 4.10's will lower my ET's? After a 5 year hiatus, I'm anxious to get the stang back to the strip.

I will get some pictures up and also will update what I find in the existing rearend.
 

txstang84

15 Year Member
May 21, 2005
1,639
42
69
Tuscola, tx
Feb 7, 2012
#2
  • Feb 7, 2012
  • #2
Have no idea if it'll slow you down or speed you up-but I'm anxious to see some videos and/or hear about it


Sent from my iPhone using Tapatalk
 
D

DavidEwers

Member
Sep 23, 2011
168
1
18
Somewhere in Paradise
Feb 7, 2012
#3
  • Feb 7, 2012
  • #3
it will help your ET, but it will decrease your MPG. Other that the suspension mods what have you done.
 

Jason 302

10 Year Member
Aug 9, 2003
685
71
68
Newark, Ohio
Feb 7, 2012
#4
  • Feb 7, 2012
  • #4
Gas mileage smass mileage . I can get 23mpg with the 3.73's if I cruised nice and easy down the highway.

Changes that I've made since I ran the 12.44 in 2006...

- Tubular A-arms with coil over kit (- 30lbs)
- KYB adjustable struts and shocks
- Soon to be rear seat delete (approx 20-30lbs)
- Polyurethane bushing aftermarket rear control arms w/battle box reinforcements
- Fixed a bad vacuum and oil leak (not sure how much of that was going on during the 12.44 run)
- Soon to swap 3.73's for some 4.10's and a better LSD

My goal is to run AT LEAST 12.30's this year....but teens would be nice. Next winter I plan on installing a tubular K-member that I have laying around and maybe massaging the 306 a little further if the funds allow it.
 

CarMichael Angelo

my rearend will smell so minty fresh,
15 Year Member
Nov 29, 1999
10,641
8,909
234
Birmingham, al
Feb 7, 2012
#5
  • Feb 7, 2012
  • #5
Jason 302 said:
So after recently installing some new rear control arms and battle boxes, I noticed I have a considerable amount of slop in my driveshaft without any movement from the axles. My pops seems to think a lot of it is coming from the axle splines, but I think it has too much backlash between the ring and pinion as well. I'll inspect it soon.

I had it re-built about 9 years ago by a local guy here. Stock 28 spline axles, stock re-built trac-lok, stock differential cover, and FRPP 3.73 gears. After many 6000rpm street slick launches and 9 years of street abuse, I think it is time for a overhaul.

I've had a spare rearend housing laying around for about 5-6 years. I tried setting it up around that time period, but could never get the tooth pattern that I wanted. Even after numerous pinion shim changes and backlash adjustments...I finally gave up lol.

Fast forward to today. I dropped the housing and parts off to a reputable shop here locally to have the following parts installed and setup.

- FRPP 4.10 gears (from 3.73's)
- Detroit TrueTrac differential (from Trac-Lok, interested to see how well it works at the strip)
- Solid pinion crush sleeve

I already had the axle bearings and seals installed as well as the pinion bearing races and seal.

When it gets home it will be receiving some Moser 31 spline axles and an aluminum differential cover.

Anybody have any guesses whether or not the 4.10's will lower my ET's? After a 5 year hiatus, I'm anxious to get the stang back to the strip.

I will get some pictures up and also will update what I find in the existing rearend.
Click to expand...

HA! you are doing zactly what I did. (tried to do it myself, and finally gave up and paid somebody who knows what they're doing to do it).
 

Jason 302

10 Year Member
Aug 9, 2003
685
71
68
Newark, Ohio
Feb 12, 2012
#6
  • Feb 12, 2012
  • #6
Ring and pinion are setup. Now I'm just waiting on the axles and studs to arrive. I'll probably update everything in my other thread....
http://www.stangnet.com/mustang-forums/threads/shes-whipped-back-into-shape-again-pics.850742/

One thing that concerns me...I have a DVD on how to re-build the Ford 8.8 axle. In the DVD the guy says that the carrier caps should have the arrows pointing outward, but mine are pointing inward. I told the guys building it that the caps had probably lost their correct place over the years, so I didn't know which cap went to which side. He said they had ways of finding out, so hopefully they know what they're doing.
 

ID89GT

10 Year Member
May 26, 2008
1,659
18
49
Spokane Valley, WA
Feb 12, 2012
#7
  • Feb 12, 2012
  • #7
How much did a shop charge charge you to do it all? I want to have mine built using 31 spline unit, but I don't know what unit I want to go with yet.
 

Jason 302

10 Year Member
Aug 9, 2003
685
71
68
Newark, Ohio
Feb 12, 2012
#8
  • Feb 12, 2012
  • #8
Around $370 in labor but they said the labor would of been less if I hadn't of furnished my own parts.
 
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