• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

Ford 8.8 ring gear contact patch always favors heel edge


ylidk

Well-Known Member
Joined
Jul 16, 2018
Messages
53
Reaction score
7
Location
KS
Vehicle Year
1991
Make / Model
Ford
Engine Size
2.3l L4
Transmission
Manual
Hey all, I am regearing my truck from 3.08's to 3.55's and replacing the open diff to a limited slip. All used, stock Ford parts. I am having trouble getting the contact patch looking good though, the drive side always seems to favor the toe edge while the coast side always seems to favor the heel edge. Based on the Ford guide (image below) this implies that the pinion shim needs to be thinner, but I dropped from 0.032 all the way down to 0.010 in steps, and the coast side was always on the heel edge. I was able to get the drive side looking okay at 0.027" pinion shim thickness, and with backlash at 0.008" shown in the image below. I can live keeping that drive side pattern at 0.027" pinion shim thickness, but the coast side looks pretty bad, and nothing I change seems to do much at all? At 0.010" It actually seemed more dramatically at the heel edge than higher shim thicknesses. Any ideas? Been at it for a few days and it's about to rain for a week straight here, so I want to have this project sealed up before then if I can. TIA!




1711748853214.png
signal-2024-03-29-173803_002.jpeg
signal-2024-03-29-173803_003.jpeg
 
Last edited:


2011Supercab

Well-Known Member
Joined
Dec 10, 2021
Messages
624
Reaction score
651
Location
Washington
Vehicle Year
2023
Make / Model
Toyota Tacoma
Transmission
Automatic
2WD / 4WD
4WD
Backlash is adjusted by moving the carrier to one side or the other by changing the shims on the sides of the carrier.

Not by changing the shims on the pinion gear
 

ylidk

Well-Known Member
Joined
Jul 16, 2018
Messages
53
Reaction score
7
Location
KS
Vehicle Year
1991
Make / Model
Ford
Engine Size
2.3l L4
Transmission
Manual
Backlash is adjusted by moving the carrier to one side or the other by changing the shims on the sides of the carrier.

Not by changing the shims on the pinion gear
Backlash spec is 0.008" to 0.012", and my backlash is measuring in at 0.008". My pattern has always kept looking similar to example B. in ford's guide.
 
Last edited:

2011Supercab

Well-Known Member
Joined
Dec 10, 2021
Messages
624
Reaction score
651
Location
Washington
Vehicle Year
2023
Make / Model
Toyota Tacoma
Transmission
Automatic
2WD / 4WD
4WD
every time you change pinion depth you need to recheck the backlash
 

ylidk

Well-Known Member
Joined
Jul 16, 2018
Messages
53
Reaction score
7
Location
KS
Vehicle Year
1991
Make / Model
Ford
Engine Size
2.3l L4
Transmission
Manual
every time you change pinion depth you need to recheck the backlash
Yep, I have been. I've had the gears out probably 50 times to get these shims changed around to make everything play nice but the pattern never looks good. Current backlash is 0.0085". About the best I can get it in the images above. How bad would it be to send it as-is? Does the contact pattern make you think the backlash is off or something?
 

02FX4

Active Member
U.S. Military - Veteran
Joined
Mar 23, 2024
Messages
38
Reaction score
24
Location
WA, USA
Vehicle Year
2002
Make / Model
Ford Ranger FX4
Engine Type
4.0 V6
Engine Size
4.0L
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
Factory Lift
Tire Size
31"x10.5"R15
Hey all, I am regearing my truck from 3.08's to 3.55's and replacing the open diff to a limited slip. All used, stock Ford parts. I am having trouble getting the contact patch looking good though, the drive side always seems to favor the toe edge while the coast side always seems to favor the heel edge. Based on the Ford guide (image below) this implies that the pinion shim needs to be thinner, but I dropped from 0.032 all the way down to 0.010 in steps, and the coast side was always on the heel edge. I was able to get the drive side looking okay at 0.027" pinion shim thickness, and with backlash at 0.008" shown in the image below. I can live keeping that drive side pattern at 0.027" pinion shim thickness, but the coast side looks pretty bad, and nothing I change seems to do much at all? At 0.010" It actually seemed more dramatically at the heel edge than higher shim thicknesses. Any ideas? Been at it for a few days and it's about to rain for a week straight here, so I want to have this project sealed up before then if I can. TIA!




View attachment 108258 View attachment 108259View attachment 108260
Sometimes your pinion depth can cause excessive (coast) heel and (drive) toe patterns that can't be remedied by setting backlash. Most of the time you'll have to move the pinion in by removing a shim (or replacing with a thinner) and the try resetting your backlash.
 

ylidk

Well-Known Member
Joined
Jul 16, 2018
Messages
53
Reaction score
7
Location
KS
Vehicle Year
1991
Make / Model
Ford
Engine Size
2.3l L4
Transmission
Manual
Sometimes your pinion depth can cause excessive (coast) heel and (drive) toe patterns that can't be remedied by setting backlash. Most of the time you'll have to move the pinion in by removing a shim (or replacing with a thinner) and the try resetting your backlash.
Yeah, I started with a pinion shim thickness of 0.032" and based on the ford guide the toe-heel pattern I was getting implied I needed to reduce shim thickness. I reduced in steps down to 0.010" shim thickness and made sure my backlash was within the 0.008"-0.012" range in the spec. At 0.027" pinion shim thickness the drive side had the most coverage, but the coast side was always leaning toward the heel during that entire range. By 0.010" the drive side was excessively toward the heel as well.
 

02FX4

Active Member
U.S. Military - Veteran
Joined
Mar 23, 2024
Messages
38
Reaction score
24
Location
WA, USA
Vehicle Year
2002
Make / Model
Ford Ranger FX4
Engine Type
4.0 V6
Engine Size
4.0L
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
Factory Lift
Tire Size
31"x10.5"R15
Sometimes your pinion depth can cause excessive heel patterns that can't be remedied by setting backlash. Most of the time you'll have to move the pinion in by removing a shim (or replacing with a thinner) and the try resetting your backlash.
Yeah, I started with a pinion shim thickness of 0.032" and based on the ford guide the toe-heel pattern I was getting implied I needed to reduce shim thickness. I reduced in steps down to 0.010" shim thickness and made sure my backlash was within the 0.008"-0.012" range in the spec. At 0.027" pinion shim thickness the drive side had the most coverage, but the coast side was always leaning toward the heel during that entire range. By 0.010" the drive side was excessively toward the heel as well.
The coast side isn't all that critical, if you can get the drive side centered and even, then I'd send it as long as your backlash is within tolerance.
 

ylidk

Well-Known Member
Joined
Jul 16, 2018
Messages
53
Reaction score
7
Location
KS
Vehicle Year
1991
Make / Model
Ford
Engine Size
2.3l L4
Transmission
Manual
Awesome, in that case I will set set get a few patterns tested around the 0.027" shim depth and send it. Thanks!
 

Curious Hound

Formerly EricBphoto
TRS Event Staff
TRS Forum Moderator
Supporting Member
U.S. Military - Veteran
TRS 20th Anniversary
VAGABOND
TRS Event Participant
GMRS Radio License
TRS 25th Anniversary
Joined
Feb 7, 2016
Messages
16,725
Reaction score
19,303
Age
60
Location
Wellford, SC
Vehicle Year
1993
Make / Model
Ford Ranger
Engine Type
3.0 V6
Engine Size
3.0L
Transmission
Manual
2WD / 4WD
4WD
Total Lift
6"
Tire Size
35"
My credo
In theory, theory and practice are the same. In practice, they are different.
Some of this could be due to the fact that they are “used” parts. Wear patterns from previous use could be messing with you. I think that drive side pattern is pretty good.
 

4x4junkie

Forum Staff Member
TRS Forum Moderator
Article Contributor
TRS 20th Anniversary
Joined
Aug 19, 2001
Messages
10,824
Reaction score
644
Location
So. Calif (SFV)
Vehicle Year
1990
Make / Model
Bronco II
Engine Type
2.9 V6
Engine Size
2.9L V6
Transmission
Manual
2WD / 4WD
4WD
Tire Size
35x12.50R15
I have seen it mentioned a few times that (for the reason ericbphoto mentions) you want to focus more attention on the coast side when setting up used gears (coast side having less wearing-in). Your coast pic seems to indicate you need a (much) thinner pinion shim, but you're saying you've tried all the way down to 0.010 (meanwhile the drive pattern looks like an ever-so-slightly thicker shim could be used, maybe .002-.003" thicker), so I'm at a loss on this one.

Does the axle housing you're using have any past history (such as blown-up diffs, stripped gears, etc.)? Are the patterns (and backlash) consistent everywhere around the gear? How many miles are on those gears (if you know)?
 

Sponsored Ad


Sponsored Ad

Today's birthdays

TRS Events

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Truck of The Month


Rick W
October Truck of The Month

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

25th Anniversary Merch

Follow TRS On Instagram

25th Anniversary Sponsors

TRS-3 Ford Ranger Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top