Swapping open 7.5 3.73 for LSD 4.10s, direct swap


DanielLiam

New member
Joined
Mar 31, 2020
Messages
9
Reaction score
0
Points
1
Location
Portland, OR, United States
Vehicle Year
2005
Make / Model
Ford Ranger
Transmission
Manual
Hi all!

I am new to rebuilding rangers (I left my last one alone mechanically). I am making some upgrades to my 2005 2.3l RWD XL. I want to switch the open 3.73 7.5 for a LSD 4.10 rear end. Does it matter whether I do a 7.5 or 8.8? If I get it out of another ranger (Non FX) will it bolt right in? I don't want to mess with custom axle shafts. I would love it to be as plug and play as possible.

I am upgrading the axle for more traction and to accommodate a switch to 30s or 31s (I haven't decided yet). I also drive this back and forth to the mountain for snowboarding and camping and want the extra traction that a LSD would give. Additionally, I want to be able to do some light off-roading when mountain biking, hiking, and mountaineering. I don't need anything incredible or I would sell it and buy a 4wd. I want to keep the fuel mileage of the 4cyl with improved capacity for playing in the mountains. I would love your recommendations.

Thanks!!!
 


Rock Auto 5% Discount Code: 32B05A80BF19AF Expires: July 1st, 2020

gaz

Active member
Joined
Sep 21, 2007
Messages
240
Reaction score
30
Points
28
Location
Wa, Bremerton 98310
Vehicle Year
1987
Make / Model
Ford
Engine Size
2.9l
Transmission
Automatic
I don't know about the hardware with the 2.3's but going from 7.5" to 7.5" was a strait swap; going from 7.5" to 8.8", I had to have drive line changes made. From what I remember the 8.8" had different flanges, larger bolt spacing.
 

DanielLiam

New member
Joined
Mar 31, 2020
Messages
9
Reaction score
0
Points
1
Location
Portland, OR, United States
Vehicle Year
2005
Make / Model
Ford Ranger
Transmission
Manual
Thanks! That is what I was kind of wondering was if the 8.8 would have different parts. I will look for the 7.5 with 4.10s I can't think of any reason I would need the 8.8 for what I am doing.
 

Dirtman

Who pissed in my Cheerios?
EMT / Paramedic
Joined
May 28, 2018
Messages
9,115
Reaction score
5,383
Points
113
Location
Over there --->
Vehicle Year
2009
Make / Model
Ford
Engine Type
2.3 (4 Cylinder)
Engine Size
466.63 teaspoons.
Transmission
Automatic
2WD / 4WD
2WD
Tire Size
So friggin big!
My credo
RUM HAM!!!
No real reason to go to an 8.8, especially with a 2.3. You can find 7.5s with 4.10s (common axle on the 2.3 automatic trucks) and they had LS as an option look for a door tag that says R7 I think. 87 is 4.10 open. Another 7.5 is gonna be direct bolt on, 8.8 is gonna need minor tweeks but nothing at all major.
 

DanielLiam

New member
Joined
Mar 31, 2020
Messages
9
Reaction score
0
Points
1
Location
Portland, OR, United States
Vehicle Year
2005
Make / Model
Ford Ranger
Transmission
Manual
No real reason to go to an 8.8, especially with a 2.3. You can find 7.5s with 4.10s (common axle on the 2.3 automatic trucks) and they had LS as an option look for a door tag that says R7 I think. 87 is 4.10 open. Another 7.5 is gonna be direct bolt on, 8.8 is gonna need minor tweeks but nothing at all major.
Thank you Dirtman! This is exactly the info I was looking for. I am finding lots of them in junkyards for $150-$300. I will probably order one and make it a quarantine project.

I see some have 9" brakes and some have 10" brakes, does it matter? Will they both swap the same? Thanks!
 

Dirtman

Who pissed in my Cheerios?
EMT / Paramedic
Joined
May 28, 2018
Messages
9,115
Reaction score
5,383
Points
113
Location
Over there --->
Vehicle Year
2009
Make / Model
Ford
Engine Type
2.3 (4 Cylinder)
Engine Size
466.63 teaspoons.
Transmission
Automatic
2WD / 4WD
2WD
Tire Size
So friggin big!
My credo
RUM HAM!!!
Your truck currently has 9" brakes. Wont make a difference either way. The 10" brakes are obviously bigger but I highly doubt you would notice any difference. Parking brake cables are the same as far as I remember.

If you look at one in the junkyard, 9" brakes have fins on the drums. 10" brake drums are smooth.
 

DanielLiam

New member
Joined
Mar 31, 2020
Messages
9
Reaction score
0
Points
1
Location
Portland, OR, United States
Vehicle Year
2005
Make / Model
Ford Ranger
Transmission
Manual
No real reason to go to an 8.8, especially with a 2.3. You can find 7.5s with 4.10s (common axle on the 2.3 automatic trucks) and they had LS as an option look for a door tag that says R7 I think. 87 is 4.10 open. Another 7.5 is gonna be direct bolt on, 8.8 is gonna need minor tweeks but nothing at all major.

I have found a few R7s, no F7s yet. If I can't find an F7, is there a way to tell which R7s will be easiest to bolt in? I know I want to avoid a 31 spline but am unsure how to figure out which is which. I am going to probably order it in from a salvage yard somewhere so I am trying to go off make/model and door tag.

Thanks!
 

don4331

Active member
V8 Engine Swap
Joined
Sep 6, 2013
Messages
899
Reaction score
122
Points
43
Location
Calgary, AB
Vehicle Year
1999
Make / Model
Ford
Engine Type
V8
Engine Size
5.3
Transmission
Automatic
So long as the R7 isn't from a '10-11 (disc brakes, VVS sensors at wheels), they are all more/less the same from '93 to '09.

Personally, I would take a R7 out of an '03-07 FX4 Lvl II if all else was same (price, mileage, rust, etc) - 4.10s, 31 spline axles and the Torsen LS. That way you don't need to worry about the clutch packs in the LS being worn out as the Torsen uses gears. While you might not need the extra capacity of the 31 spline axles, their difference in weight/turning resistance would take laboratory conditions to measure. And you want the cables (or more likely replace with new) as the the 8.8 cable are slightly different - 7.5 cables will work, but they aren't quite right - I can't remember if its at limit of too loose or too tight, but you don't have much tolerance when mixing.

One thing to note: VVS ring in 8.8 has 108 teeth, while that in 7.5 only has 102. I don't know how well that plays with ABS. My truck is older '99 and the delta between 7.5 and 8.8 completely masked the increase in tire size between 31x10.5R15s and the OEM 235/75R15s. But my '99 gets everything from axle, while your '05 pulls speed from the transmission.

The 10" brakes make a HUGE difference. Not only are they 1" (~10%) bigger diameter, they are 3/4" wider (~33%), the result being they provide almost 50% more braking on rear. Ensure your truck has RABS or ABS (and it it working) or in panic stop, the rear wheels will lock and if truck isn't moving perfectly straight, back will attempt to pass the front. Personally, I like the fact that 10" rear brakes are "earning their keep", but I also recognize I am trusting the RABS.
 

DanielLiam

New member
Joined
Mar 31, 2020
Messages
9
Reaction score
0
Points
1
Location
Portland, OR, United States
Vehicle Year
2005
Make / Model
Ford Ranger
Transmission
Manual
So long as the R7 isn't from a '10-11 (disc brakes, VVS sensors at wheels), they are all more/less the same from '93 to '09.

Personally, I would take a R7 out of an '03-07 FX4 Lvl II if all else was same (price, mileage, rust, etc) - 4.10s, 31 spline axles and the Torsen LS. That way you don't need to worry about the clutch packs in the LS being worn out as the Torsen uses gears. While you might not need the extra capacity of the 31 spline axles, their difference in weight/turning resistance would take laboratory conditions to measure. And you want the cables (or more likely replace with new) as the the 8.8 cable are slightly different - 7.5 cables will work, but they aren't quite right - I can't remember if its at limit of too loose or too tight, but you don't have much tolerance when mixing.

One thing to note: VVS ring in 8.8 has 108 teeth, while that in 7.5 only has 102. I don't know how well that plays with ABS. My truck is older '99 and the delta between 7.5 and 8.8 completely masked the increase in tire size between 31x10.5R15s and the OEM 235/75R15s. But my '99 gets everything from axle, while your '05 pulls speed from the transmission.

The 10" brakes make a HUGE difference. Not only are they 1" (~10%) bigger diameter, they are 3/4" wider (~33%), the result being they provide almost 50% more braking on rear. Ensure your truck has RABS or ABS (and it it working) or in panic stop, the rear wheels will lock and if truck isn't moving perfectly straight, back will attempt to pass the front. Personally, I like the fact that 10" rear brakes are "earning their keep", but I also recognize I am trusting the RABS.
I think that upgrading from a 28 spline to a 31 spline might be more work than I want to get in to. I like the idea of using the F7 to keep it a simple swap. How much of a challenge is the conversion from the stock 28 to the larger 31?
 

don4331

Active member
V8 Engine Swap
Joined
Sep 6, 2013
Messages
899
Reaction score
122
Points
43
Location
Calgary, AB
Vehicle Year
1999
Make / Model
Ford
Engine Type
V8
Engine Size
5.3
Transmission
Automatic
You're buying a complete axle most likely - brake drum to brake drum. Assuming that, there are 4 differences:

1. Any 8.8 will have different flange on the end of the drive shaft. If you get an 8.8, you need to get the driveshaft flange - it will go on your driveshaft, you just need to press the 7.5 off the end u-joint and install the 8.8 one. I'd replace the u-joint at same time if you have done so recently - the truck is 15 years old. Alternatively, you get the driveshaft with the 8.8. Probably costs about the same.

2. 99% of 8.8s will have 10" brakes, as covered above. In theory, you can pull the axles out of your 7.5, unbolt your existing brakes, do the same with the new axle, and bolt your 9" backing plates on new housing, reinstall the axles, refill with fluids and you're off. This saves bleeding brakes, but you put the work in elsewhere.

3. Parking brake cables covered above, close but not identical.

4. '03-07 FX4 Lvl II has larger tubes so you need different u-bolts/plates. According to the Ford manual, you're supposed to replace the u-bolts anyways, so you want to get the plates with the axle. If you left the guys pulling the axle know you want the plates, they probably throw them in. F-150 8.8 has the same diameter tubes as Ranger FX4 Lvl II, so u-bolts and plates are common.

Assuming you have the correct parts, driveshaft flange, u-bolts & plates, bolting in a 31 spline 8.8 isn't any more work than bolting in a different 28 spline 7.5.

Note: The flange bolts are 12mm 12 pt heads and they are lock-tite in place. You want a good 1/2" drive socket and to have eaten your Wheaties when you want to undo them. I usually have a 3' pipe on the sliding t-bar to undo them. The alternate is to heat the flange and burn out the lock-tite, but I don't like that kind of heat on things.
 

scotts90ranger

Well-known member
RBV's on Boost
Joined
Feb 28, 2001
Messages
4,271
Reaction score
182
Points
63
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"
The driveshaft flange was ONLY different between the two BEFORE 1990, after that they used the same on both from everything I've heard, I just put a stock Ranger driveline in my '90 a couple weeks ago and I have an Explorer 8.8 in it, didn't have to do anything and it most likely wasn't an 8.8 truck I got it from (not many regular cab short bed 4x4 4.0L Rangers out there from what I've heard)

You don't have to think quite so deep, it's a direct swap 7.5" or 8.8", on a 2 wheel drive you can have driveline length issues if going to a 8.8" though since the snout is about an inch longer, 7.5" to 7.5" is an afternoon project in Oregon, assuming your Ranger has been around here most of it's life... If you find a 8.8 like said above if you find one with the same body style (standard cab or extended and short or long bed, doesn't matter which engine or transmission I believe) take the drive shaft. Should be able to take the driveshaft off (12mm 12 point wrench and a propane or butane torch does wonders), two shock bolts off (lower works), jack stands on the frame somewhere, take the parking brake cable apart, undo the rear brake line at the top of the differential, unplug the speed sensor next to that, undo the 8 U bolt nuts and support the differential. Reinstall is reverse of removal other than bleeding the brakes afterward.

I'm wanting similar for my '97, but I have tools and I've done the swap before so I'm going to do a disc brake Explorer 8.8 with LS 4.10's if I can find one, I already have 4.10's but open and traction is lacking...
 

don4331

Active member
V8 Engine Swap
Joined
Sep 6, 2013
Messages
899
Reaction score
122
Points
43
Location
Calgary, AB
Vehicle Year
1999
Make / Model
Ford
Engine Type
V8
Engine Size
5.3
Transmission
Automatic
The yards I frequent don't allow torches. And they seem to like to pick up vehicles on their loader by the driveshaft, so finding an unbent one locally is challenge.

And yes, Ford Engineers put the end of the transmission in exactly same spot for both manual & autos, so as long as body style is same, engine or transmission doesn't matter.

FWIW: 98+ RCSB Rangers and 4 door Explorers have exact same wheelbase = exact same driveshaft.

I undo the brake line at the frame - to each his own there, its 6 of one, 1/2 dozen of other.
 

gaz

Active member
Joined
Sep 21, 2007
Messages
240
Reaction score
30
Points
28
Location
Wa, Bremerton 98310
Vehicle Year
1987
Make / Model
Ford
Engine Size
2.9l
Transmission
Automatic
Daniel:

My 1st swap was a 7.5" to a 7.5" with 4:10's and the 10" drums from 9" drums. It made a noticable improvement in braking. I was concerned that I may need to change my front/rear proportion valve but it just made stopping feel better all around.

Initially when I did it, the parts guy would get confused, I learned just to say that I needed the 10" set.
 

DanielLiam

New member
Joined
Mar 31, 2020
Messages
9
Reaction score
0
Points
1
Location
Portland, OR, United States
Vehicle Year
2005
Make / Model
Ford Ranger
Transmission
Manual
Wow, thanks for all the knowledge guys. You all are a treasure trove!

I definitely feel more comfortable jumping up to an R7 now and those are much easier to find.

It is an Oregon truck so there is almost no rust. Having grown up in Michigan, I love now living in a state that doesn't salt the roads.

I switched my plans to a 30x9.5x15. I was previously on the fence about this but Hankook is clearing out their Dynapro ATM for $84.79 each on Amazon so that sold me on keeping the smaller tire. I still think I will like having 4.10s on there but it buys me a little more time to find the right rear end (it also makes the rear end basically "free" when I consider what I saved over buying the 31" BFG TA K02s I was considering)
 


Top