• 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.

Diff swap or rebuild?


SamC777

New Member
Ham Radio Operator
Joined
Jun 29, 2023
Messages
23
Reaction score
8
Points
3
Location
Oklahoma
Vehicle Year
1994
Make / Model
Ford Ranger
Engine Type
3.0 V6
Transmission
Manual
2WD / 4WD
4WD
94 Ranger, 3.0, 4WD. Dana 35. 3.73 7.5" ~330k miles

Earlier this month, my truck started making a rhythmic "thud" sound. Lifted the rear end up and drove it and sure enough, it was coming from my diff. I'm told this could be the pinion bearing, which makes sense to me because there were a lot of metal shavings on the ABS sensor when I replaced it the month before.

The fluid is 3 years old, and it's had about 25k miles since then. The ring gear has been missing a tooth since before I bought this truck 5 years ago, but I haven't had any noticeable issues while driving it. However, my thinking is that if I'm going to pull the ring and pinion out to replace the bearing, I may as well replace those too while I'm in there. That said, I've never serviced my diff beyond a fluid change. I'm certain I can figure it out, but I won't know for sure what else is damaged and what's not. The whole differential might need to be replaced for all I know.

On the other hand, I could just go to the Land of Misfit Parts and pull a rear end. I'm uneducated in this area as well, as once again, I don't know how to tell a good one from the bad even if I pull the cover off. But this may be the simpler (and possibly cheaper) route. Additionally, I've been told that the 8.8" gear is more reliable than the 7.5". Is this true?

Which option do you folks recommend?
Do you have any advice on what to look out for?

Thanks
 


Northidahotrailblazer

Well-Known Member
Joined
Feb 21, 2012
Messages
439
Reaction score
541
Points
93
Location
Northern Idaho
Vehicle Year
1992
Make / Model
Ford Ranger
Engine Type
4.0 V6
Transmission
Manual
2WD / 4WD
Solid Axle Swap 4x4
Total Lift
8 inches
Tire Size
37"
When I tried to sell my 7.5 no one wanted it. I’m sure you could get one from a junk yard for cheap. Under or around $100 bucks. A gear setup kit will cost you around $100 bucks also. Which is the better way to go rather than just buying bearings.

you can’t just replace the bearings, and not check gear patterns. new bearings will make tolerances change, and to do it right you will have to pretty much reset up the gears. Which shouldn’t be to far off. Since you’re not regearing. You don’t know what’s wrong until you pull the cover. You could have more damage than a bearing and at that point it’s way cheaper to just get a junk yard axle.
 

Eddo Rogue

Well-Known Member
Joined
May 18, 2020
Messages
3,987
Reaction score
2,508
Points
113
Location
Burbank,CA
Vehicle Year
1993
Make / Model
Ranger 4x4
Engine Type
4.0 V6
Engine Size
OHV
Transmission
Manual
2WD / 4WD
4WD
Total Lift
skyjacker front leveling kit
Tire Size
31-10.50R15
My credo
Crossed threads are tight threads.
I would rebuild it. Whatever you pull is not gonna have fresh internals. Probably will need seals and stuff anyways.

I done a few ring and pinion jobs. Honestly its not rocket science. Pretty much a magnetic dial indicator is the only unique special tool required.

I thought reading the gear mesh pattern was some kind of dark voodoo art, but it quite obvious to tell. Most rebuild kits come with the pattern marking paint stuff.

Do yourself a favor and get the complete kit, not just the ring and pinion...the kit has all the seals, gaskets, bearings, shims, crush sleeve etc...

Oh and trick of the trade is give the crush sleeve a few whacks with a brass hammer before torquing down to ensure it crushes down nice

The only real quessing game is getting the shimming right, but I have never had to re shim and measure again more than twice...maybe lucky.
 

CamTheHedgehog

Well-Known Member
ASE Certified Tech
GMRS Radio License
Joined
Jul 24, 2023
Messages
313
Reaction score
461
Points
63
Location
From Charlotte, NC; Living in Lansing, IA
Vehicle Year
2003
Make / Model
Ranger Edge
Engine Type
4.0 V6
Engine Size
4.0 SOHC
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
Torsion Bar Max Crank (Pre-2008)
Tire Size
265/75/16
My credo
Professional Dingus At Work
I would rebuild it. Whatever you pull is not gonna have fresh internals. Probably will need seals and stuff anyways.

I done a few ring and pinion jobs. Honestly its not rocket science. Pretty much a magnetic dial indicator is the only unique special tool required.

I thought reading the gear mesh pattern was some kind of dark voodoo art, but it quite obvious to tell. Most rebuild kits come with the pattern marking paint stuff.

Do yourself a favor and get the complete kit, not just the ring and pinion...the kit has all the seals, gaskets, bearings, shims, crush sleeve etc...

Oh and trick of the trade is give the crush sleeve a few whacks with a brass hammer before torquing down to ensure it crushes down nice

The only real quessing game is getting the shimming right, but I have never had to re shim and measure again more than twice...maybe lucky.
Don't they also make intentionally slip fit bearings for setting up the shims, so you aren't pressing bearings on and off constantly?
 

sgtsandman

Aircraft Fuel Tank Diver
TRS Forum Moderator
U.S. Military - Active
TRS 20th Anniversary
TRS Event Participant
Ham Radio Operator
GMRS Radio License
TRS 25th Anniversary
Joined
Mar 11, 2017
Messages
13,292
Reaction score
13,442
Points
113
Location
Aliquippa, PA
Vehicle Year
2011/2019
Make / Model
Ranger XLT/FX4
Engine Size
4.0 SOHC/2.3 Ecoboost
2WD / 4WD
4WD
Total Lift
Pre-2008 lift/Stock
Tire Size
31X10.5R15/265/65R17
Don't they also make intentionally slip fit bearings for setting up the shims, so you aren't pressing bearings on and off constantly?
The shims fit between the bearings and the housing for the carrier, if I remember things correctly. So once the bearings are pressed on, you shouldn't need to mess with them again while trying to set the back lash and tooth engagement.

For the pinion, on the other hand, that is a different story. I remember a couple people using an identical brand bearing to the one they are going to permanently install for setup. They reamed out the inside of the bearing so that it would fit snug but not need a press to get it on and off the pinion. Once they got the pinion depth right, then they would press on the permenant bearing for final installation.
 

Roert42

Well-Known Member
RBV's on Boost
TRS Event Participant
Joined
Apr 24, 2020
Messages
4,930
Reaction score
5,236
Points
113
Location
Kintersville, PA
Vehicle Year
2011
Make / Model
Ranger XLT
Engine Size
4.0 SOHC
Transmission
Automatic
2WD / 4WD
2WD
Don't they also make intentionally slip fit bearings for setting up the shims, so you aren't pressing bearings on and off constantly?
I hogged out the id of the old bearing I was replacing last time I’d did it.



If you have to buy new gears and everything, it would be easier to just get a new axle. If the new axel is going to need seals and such, it’s probably a wash.
 

19Walt93

Well-Known Member
Ford Technician
V8 Engine Swap
Joined
Nov 13, 2018
Messages
4,622
Reaction score
4,610
Points
113
Location
Canaan,NH
Vehicle Year
1993
Make / Model
Ford Ranger
Engine Type
V8
Engine Size
351
Transmission
Automatic
2WD / 4WD
2WD
Total Drop
3"
Tire Size
235/55R16
My credo
If you don't have time to do it right will you have time to do it over?
I would tear it apart and see what you've got before deciding or buying any parts. My truck came with a 3.73, Traction Lok, 8.8 rear that had the spring pads moved to the bottom of the axle tubes to lower the truck. I was using a C4 with no overdrive so I was going to swap in some 3.08's. I found the pinion flange and both axles scored where the seals rode so they were junk, the Traction Lok clutches were worn to metal and grinding into the differential housing so it was junk, and the spring pads were welded on at 2 different angles- neither one was right.
I rebuilt my spare Mustang II 8 inch rear and got some spring pads and 5 lug axles from Currie.
 

scotts90ranger

Well-Known Member
RBV's on Boost
Joined
Feb 28, 2001
Messages
8,358
Reaction score
4,885
Points
113
Location
Dayton Oregon
Vehicle Year
1990, 1997
Make / Model
Ford
Engine Type
2.3 (4 Cylinder)
Engine Size
2.3 Turbo
Transmission
Manual
2WD / 4WD
4WD
Total Lift
6
Tire Size
35"
I would replace the whole axle, way cheaper, sure it's unknown but setting up gears isn't for everyone...

Finding a '93-09 rear axle with 3.73's shouldn't be all that hard.
 

scotts90ranger

Well-Known Member
RBV's on Boost
Joined
Feb 28, 2001
Messages
8,358
Reaction score
4,885
Points
113
Location
Dayton Oregon
Vehicle Year
1990, 1997
Make / Model
Ford
Engine Type
2.3 (4 Cylinder)
Engine Size
2.3 Turbo
Transmission
Manual
2WD / 4WD
4WD
Total Lift
6
Tire Size
35"
Just a note, I'm not saying this because I think you can't or shouldn't, and I for sure understand the want to be able to do everything yourself, I haven't farmed anything out but windshields and tire balancing for many years (conveniently I do have a friend that does transmissions for a living so that helps greatly there...).

Assuming you have a spare vehicle and are not trying to get this done over the weekend with just youtube videos so you can make it to work on Monday, give it a shot but you'll have at least $200 in gears, another $150 in a master rebuild kit or you could just get a used axle for $150 to $300 and throw the axle seals and maybe pinion seal in and call it... swapping axles is simple, it was one of the first modifications I did on my '90 going from 3.08 gears to 3.73...
 

SenorNoob

Well-Known Member
TRS Event Participant
Joined
Oct 24, 2012
Messages
2,657
Reaction score
736
Points
113
Location
Middle Tennessee
Vehicle Year
1988
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0
Transmission
Manual
2WD / 4WD
4WD
Total Lift
1.5" Front + 4" Rear
Tire Size
245-70-R16
I'd rather go the axle swap route myself. I've done straight gears on a conveyor and it was a nightmare.
Too bad the 4.10 Dana 35 is as rare as quality pictures of bigfoot.
 

Sponsored Ad


Sponsored Ad

Staff online

Today's birthdays

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


TexasDuck66
July Truck of The Month

Recently Featured

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

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top