Another Axle Question
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Senior User
Joined: Jul 2008
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From: San Antonio, Texas
Another Axle Question
Hey Guys, Did some searching and just dug myself deeper into more questions.
Let me tell you what i got first. 1986 F-150 now with 31x10.5 tires on it.
It currently has a 3.08 8.8" rear end w/ drum brakes
What i wanted was to upgrade to a limited slip type rear end, and if possible with disc brakes but not a requirement.
Read up and realized that these 31" tires i put on are probably killing my MPG's and power with that 3.08 gear in there. So now i want to change that as well. I read the 3.55 or 4.10 may be a good idea, but wouldn't mind more thoughts on this.
But to the main question I want some insight on what rear ends will fit in my truck. I saw on some forum a 88 year with 3.55 LS and think that would fit mine but is it also possible to find these in older rear wheel drive cars like Lincolns n such as well?
If i can find one in a Truck awesome but just wanna know where else i can look for one to.
Also on that note, How can i tell if it is a Limited Slip Differential as well. The tag on mine shows 3 08 8 8 and i'm sure the one i'd want would say 3 55 8 8 but what will it show for a LS on that tag or door jam?
Thanks
Let me tell you what i got first. 1986 F-150 now with 31x10.5 tires on it.
It currently has a 3.08 8.8" rear end w/ drum brakes
What i wanted was to upgrade to a limited slip type rear end, and if possible with disc brakes but not a requirement.
Read up and realized that these 31" tires i put on are probably killing my MPG's and power with that 3.08 gear in there. So now i want to change that as well. I read the 3.55 or 4.10 may be a good idea, but wouldn't mind more thoughts on this.
But to the main question I want some insight on what rear ends will fit in my truck. I saw on some forum a 88 year with 3.55 LS and think that would fit mine but is it also possible to find these in older rear wheel drive cars like Lincolns n such as well?
If i can find one in a Truck awesome but just wanna know where else i can look for one to.
Also on that note, How can i tell if it is a Limited Slip Differential as well. The tag on mine shows 3 08 8 8 and i'm sure the one i'd want would say 3 55 8 8 but what will it show for a LS on that tag or door jam?
Thanks
Posting Guru
Joined: Apr 2009
Posts: 1,089
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From: Illernois
If i were you i'd find an scrap truck with a 9' rear end instead of another 8 8. The 9 will be stronger and swapping the third member for different gears and limited slip is quite easy.
But since you need a whole new rear end anyways id just find one with the gears you want before hand. Luckly many of these trucks came with lower gears and l/s already so it shouldnt be too hard to find.
How you can tell the ratio and if its a l/s or not is by the tag. The first three numbers will be the ratio, but i dont remember the code letter for limited slip. Hopefully someone can chim in on that.
But since you need a whole new rear end anyways id just find one with the gears you want before hand. Luckly many of these trucks came with lower gears and l/s already so it shouldnt be too hard to find.
How you can tell the ratio and if its a l/s or not is by the tag. The first three numbers will be the ratio, but i dont remember the code letter for limited slip. Hopefully someone can chim in on that.
Elder User
Joined: Nov 2005
Posts: 733
Likes: 2
If you're searching for the niner, check under the earlier trucks. I've seen lots of them under 80-82 models, but I don't think I've seen one in a later year.
Be careful with that LS in the winter, they act different when you hit ice with them
Be careful with that LS in the winter, they act different when you hit ice with them
Post Fiend
Joined: Dec 2007
Posts: 8,521
Likes: 16
From: Lost
9" rear ends were used 80-82 exclusively, and 83-86 mostly behind non OD transmissions. The 8.8" started to show up in 83 and was used thru 86 mostly behind OD transmissions, and became the only axle used in 87.
Door stickers can be decieving, as the axles could have been swapped. The axle tag is more likely to be accurate.
Both the 8.8 and 9 used the same method of indicating when an LS was installed, the ratio code had an L in the middle IE: 3L08, rather than 3.08.
During the 83-86 years, the 8.8 was not offered in anything between 3.08 and 3.55, however the 9" could be found with a 3.25, as well as 3.00 and 3.50.
80-86 9" ratios were 2.47, 2.75, 3.00, 3.25 and 3.50
83-86 8.8" ratios were 2.47, 2.73, 3.08 and 3.55
Either may have offered a 4.10, but I'm not sure how common they would have been in a 1/2 ton.
The 80-86 9" is a direct swap for the 83-86 8.8" with the possible exception of the driveshaft.
Door stickers can be decieving, as the axles could have been swapped. The axle tag is more likely to be accurate.
Both the 8.8 and 9 used the same method of indicating when an LS was installed, the ratio code had an L in the middle IE: 3L08, rather than 3.08.
During the 83-86 years, the 8.8 was not offered in anything between 3.08 and 3.55, however the 9" could be found with a 3.25, as well as 3.00 and 3.50.
80-86 9" ratios were 2.47, 2.75, 3.00, 3.25 and 3.50
83-86 8.8" ratios were 2.47, 2.73, 3.08 and 3.55
Either may have offered a 4.10, but I'm not sure how common they would have been in a 1/2 ton.
The 80-86 9" is a direct swap for the 83-86 8.8" with the possible exception of the driveshaft.
Post Fiend
Joined: Nov 2005
Posts: 7,437
Likes: 4
From: Charles Town, W bygod Va
When you're reading the tag, keep in mind that the first # is usually mostly covered by the bolt that holds the tag to the rear, so at first glance you'll just see 08 or L08 for a 3.08 ratio
Thread Starter
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Senior User
Joined: Jul 2008
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From: San Antonio, Texas
You know that 9" sounds like a good idea, when you say the drive shaft will be different, do you mean the length or just the part that connects?
I ask this because i just dropped 200$ last month to get my drive shaft rebuilt, So now it's balanced with top end u joints and new center bearing. I'm not willing to change it to a worn out one. I don't do any fancy racing or off road stuff nor hard towing with it, i just want to have a lil more traction when needed and compensate for the bigger wheels (now that i know about that lol). I found some conversion thing (new tire size X Old gear ratio) / New tire size or something like that and i came up with a number of 3.40 and then I read on that a 3.55 or around that would be perfect for 31's.
I'm sure the 8.8 well handle what i want it to do though.
EDIT* Also can a later model axle like 87 to 97 etc fit in? I wanna find the lowest mileage one i can. Thats one reason i wanna swap it to, Cause I'm hearing some whining and I've replaced the engine, the transmission, and most recent the drive shaft, and I've noticed it's still there. So figure it has to be the rearend LOL!
I ask this because i just dropped 200$ last month to get my drive shaft rebuilt, So now it's balanced with top end u joints and new center bearing. I'm not willing to change it to a worn out one. I don't do any fancy racing or off road stuff nor hard towing with it, i just want to have a lil more traction when needed and compensate for the bigger wheels (now that i know about that lol). I found some conversion thing (new tire size X Old gear ratio) / New tire size or something like that and i came up with a number of 3.40 and then I read on that a 3.55 or around that would be perfect for 31's.
I'm sure the 8.8 well handle what i want it to do though.
EDIT* Also can a later model axle like 87 to 97 etc fit in? I wanna find the lowest mileage one i can. Thats one reason i wanna swap it to, Cause I'm hearing some whining and I've replaced the engine, the transmission, and most recent the drive shaft, and I've noticed it's still there. So figure it has to be the rearend LOL!
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Post Fiend
Joined: Dec 2007
Posts: 8,521
Likes: 16
From: Lost
The driveshaft *may* be different between a 9" and 8.8". I've heard it both ways. It really depends on what vehicle you get the rearend from. The pinion length can be different, or the u-joint could be different.
I've read several places that the 8.8 and 9 used in the 80-86 models will interchange without needing any DS mods, and I have a freind that swapped a 9" under his 86 F150 that swears the DS was the same. Of course, he made sure to get a 9" that was from an 80-86 F150. His primary reason for the swap was he wanted to split the difference between the 3.08 and 3.55 ratios, so he went to a 3.25 9".
Ironically, I am planning to swap my 2.75 for a 3.25 for much the same reason as you stated, I'm running 31" rear tires. I have a C6, so no OD. The 3.25/31" combo will net ~2300 RPM @ 65 MPH, which is about where I want to be with my 300 I6.
If you have an OD trans, the 3.55 would certainly be a great choice. If you do not have OD, perhaps the 3.25 9" option would be a bit better, as the 3.55/31" combo will net ~2500 RPM @ 65 MPH.
Simple RPM calculator: (speed) X (final drive ratio) X 336 / (tire diameter) = RPM
Final drive = rear axle ratio X high gear trans ratio (non OD = 1:1, OD = 0.60 - 0.85 depending on trans).
I've read several places that the 8.8 and 9 used in the 80-86 models will interchange without needing any DS mods, and I have a freind that swapped a 9" under his 86 F150 that swears the DS was the same. Of course, he made sure to get a 9" that was from an 80-86 F150. His primary reason for the swap was he wanted to split the difference between the 3.08 and 3.55 ratios, so he went to a 3.25 9".
Ironically, I am planning to swap my 2.75 for a 3.25 for much the same reason as you stated, I'm running 31" rear tires. I have a C6, so no OD. The 3.25/31" combo will net ~2300 RPM @ 65 MPH, which is about where I want to be with my 300 I6.
If you have an OD trans, the 3.55 would certainly be a great choice. If you do not have OD, perhaps the 3.25 9" option would be a bit better, as the 3.55/31" combo will net ~2500 RPM @ 65 MPH.
Simple RPM calculator: (speed) X (final drive ratio) X 336 / (tire diameter) = RPM
Final drive = rear axle ratio X high gear trans ratio (non OD = 1:1, OD = 0.60 - 0.85 depending on trans).
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Thread Starter
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Senior User
Joined: Jul 2008
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From: San Antonio, Texas
Kool Kool Thanks rouge and everyone else's help to i might add, my last post was at work and tried to make it fast lol.
I do have OD in my 5spd :-) So 3.55 sounds good or 3.50 if i can do the 9" I will be sure to measure my drive shaft and such before i go out so i can hopefully find one with a shaft still possibly and measure it up.
Though i kinda did wanna just get the newest one i could find so i can expect the least amount of problems. Which would probably be a 8.8 out of a early to mid 90's Truck but i can't say what i'll decide once i get out there. Like i stated one reason i'm doing the swap to something with LS and a higher ratio is i don't wanna pay 700$ to get mine rebuilt. I wouldn't mind doing it myself but never rebuilt one and i'm sure all the bearings are in need of being replaced on it.
I do have OD in my 5spd :-) So 3.55 sounds good or 3.50 if i can do the 9" I will be sure to measure my drive shaft and such before i go out so i can hopefully find one with a shaft still possibly and measure it up.
Though i kinda did wanna just get the newest one i could find so i can expect the least amount of problems. Which would probably be a 8.8 out of a early to mid 90's Truck but i can't say what i'll decide once i get out there. Like i stated one reason i'm doing the swap to something with LS and a higher ratio is i don't wanna pay 700$ to get mine rebuilt. I wouldn't mind doing it myself but never rebuilt one and i'm sure all the bearings are in need of being replaced on it.
Cargo Master
Joined: Oct 2005
Posts: 2,298
Likes: 27
From: NJ
Do a 9 inch and a detroit. Done deal, will last a long time. You could find a Sterling for real cheap ($100) in either 3.55:1 or 4.10:1, but most were open and if you find a TrakLoc it's probably got cooked clutches. You could do a lunchbox in that for $400 or a Detroit for $700. Of course that brings the problem of 8 lug on rear and 5 lug on front. I assume the truck is 2 wheel drive since you didn't mention a front axle?
LOL But it's all i need.
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Senior User
Joined: Jul 2008
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From: San Antonio, Texas
So been awhile but i did end up buying a 8.8 3.55 with LS carrier in it at the J/yard and i bought a Traction loc disc kit and carrier bearing/seal kit online as well. Does anyone know of a good site that can break down how i can get the bearing races and axle bearings out of the housing? I'm probably gonna have to go to a shop ain't I?
Second Question is how do i take apart the carrier as in what do i do to replace the old traction loc disk's with the new ones i bought, I see a type of S looking spring but how do i get it out? Or do i need a special FORD tool to do that to? First time Doing axle work and wanna learn it!
Thanks Guys n Gurlz!
Second Question is how do i take apart the carrier as in what do i do to replace the old traction loc disk's with the new ones i bought, I see a type of S looking spring but how do i get it out? Or do i need a special FORD tool to do that to? First time Doing axle work and wanna learn it!
Thanks Guys n Gurlz!
Cargo Master
Joined: Oct 2005
Posts: 2,298
Likes: 27
From: NJ
You need one bearing pullers to use on the end of a slide hammer. Like this...
Amazon.com: OTC Tools (OTC6540) 8 Piece Rear Axle Bearing Puller Set: Home Improvement
You can use a seal driver to install the new bearing and seal.
Amazon.com: OTC Tools (OTC6540) 8 Piece Rear Axle Bearing Puller Set: Home Improvement
You can use a seal driver to install the new bearing and seal.
Thread Starter
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Senior User
Joined: Jul 2008
Posts: 164
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From: San Antonio, Texas
You need one bearing pullers to use on the end of a slide hammer. Like this...
Amazon.com: OTC Tools (OTC6540) 8 Piece Rear Axle Bearing Puller Set: Home Improvement
You can use a seal driver to install the new bearing and seal.
Amazon.com: OTC Tools (OTC6540) 8 Piece Rear Axle Bearing Puller Set: Home Improvement
You can use a seal driver to install the new bearing and seal.
So what about those Pinion Gear Bearing races? can i hammer those out? I'm sure i'll have to get a shop to press off and on the new bearings them selves on the carrier and pinion gear though. Am i correct on that?
Thanks in advanced, i can't wait to get this built and drop it in, it's kinda also holding up me putting my exhaust on to lol.
