Rear differential questions 9" vs 8.8

classic Classic list List threaded Threaded
42 messages Options
123
Reply | Threaded
Open this post in threaded view
|

Rear differential questions 9" vs 8.8

Rembrant
Folks,

Dumb question, I know...but would a 1986 F150 4x4 have a 9" rear end or 8.8? I thought by 1986 all of the 1/2 ton trucks had the 8.8 rear?

PS: Gary, I went to the Driveline > Differentials > Rear differentials page, and it comes up blank. Is it one that is under construction, or is it complete but "broken"? (Or did I do something wrong?).
1994 F150 4x2 Flareside. 5.0 w/MAF, 4R70W, stock.
1984 F150 4X2 Flareside. Mild 302 w/ 5spd. Sold.
1980 F150 4X4 Flareside. 300i6 w/ 5spd. Sold in 2021.
1980 F100 4X2 Flareside. 351w/2bbl w/NP435. Sold in 1995

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Gary Lewis
Administrator
Hmmm.  Looks like you found a big gap in the information.  

There's also a page on Rear Axles, but it isn't complete.  I'll work on that, probably tomorrow night during the World Series, and will hope to consolidate or at least refer from one page to the other.

As for whether an '86 had a 9" or an 8.8", it looks to me like the catalog says it could be either.  Here's the entry for F100's and F150's, and the WDM and WFE axles are, as it says, the 9".  And they were used through '86.

But, from what I see, if the rear axle is the lighter-duty one, meaning rated for 2,800 lbs, then it will be a 9" since the 8.8" only came with a 3,750 rating.

Now I need to record this, and the similar info about the F250/350 rear axles, in the Y2Y Differences page.  


Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Rembrant
OK Gary, thanks. I was just looking at pics of a 1986 F150 4x4 that showed up for sale locally last night. It appears to have a 9" rear diff in it, and I thought by 86 that they ALL had the 8.8 rear diff. That's all, no big deal. Thanks.
1994 F150 4x2 Flareside. 5.0 w/MAF, 4R70W, stock.
1984 F150 4X2 Flareside. Mild 302 w/ 5spd. Sold.
1980 F150 4X4 Flareside. 300i6 w/ 5spd. Sold in 2021.
1980 F100 4X2 Flareside. 351w/2bbl w/NP435. Sold in 1995

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Gary Lewis
Administrator
I'm glad you asked the question as it pointed out a large hole in the info on the website.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

PetesPonies
I have had people tell me they had '86s and maybe even '87s with a 9". I do believe at least by '88 they were all 8.8s.
Pete's Ponies
Mustang RUSToration & Performance

1982 F100 Flareside
1983 Bronco

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Gary Lewis
Administrator
I won't say they couldn't have had a 9" in an '87.  The master parts catalog indicates they weren't using them, but I'm sure Ford didn't throw anything away when it would bolt right in.

The MPC says that slide locks ended in March of '81, but I've documented trucks that were built as late as July of '81 that came with slide locks.  I think they just used up whatever supply they had of the locks.  So it is quite probable that Ford continued to use whatever supply of 9" axles they had until they ran out, and that surely varied by the manufacturing plant.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Gary Lewis
Administrator
I revised things a bit.  Discovered I had both a Rear Axles page as well as a Differentials page.  There is now one page: Driveline/Axles & Differentials and it has the info from both of those pages.  And those pages have been deleted, and a redirect to the new page created so if someone had the old ones bookmarked they'll still find the info.

I'm not really done with this new page, but it is an improvement - I think.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Bulldawg1081
In reply to this post by Rembrant
Maybe this will help.. I've been building these trucks for over 20 years.. in MY experience all 1/2 ton bullnose trucks up through 1982 came with a 9" rear no matter what engine it had.. 1983 through 1986 if the truck was a 300/6 or a 302 it came with an 8.8 BUT the 351w trucks still came with a 9".. I currently have an 86 302 truck with an 8.8 and two 86 351w trucks with factory 9" rear ends. Also you'll notice the 9" 3rd members from 83 to 86 have a longer yolk than previous years to accommodate the longer snout of an 8.8 so that driveshafts are universal.
1986 F-150 EFI 302 C6 2WD.
1980 F-100 300 C4 2WD soon to have a roller cam 351w,
1986 F-150 351W C6 4X4.
1986 F-150 351W C6 2WD *Parts truck*.
1985 E-150 351W C6 2WD  shaggin wagon.
1999 Mustang GT 4.6 T45 cruiser.
Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Rembrant
Well now I know! I thought that all of the half ton trucks had the 8.8 diff from 83 up, but I did just see an 86 4x4 with a 302 and a 9" rear diff. Interesting stuff. I like finding out these details, thanks!
1994 F150 4x2 Flareside. 5.0 w/MAF, 4R70W, stock.
1984 F150 4X2 Flareside. Mild 302 w/ 5spd. Sold.
1980 F150 4X4 Flareside. 300i6 w/ 5spd. Sold in 2021.
1980 F100 4X2 Flareside. 351w/2bbl w/NP435. Sold in 1995

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Gary Lewis
Administrator
In reply to this post by Bulldawg1081
I just confirmed that in the 1984 facts book.  It says that everything but the 351's got 3.55 gears, but the 351's got 3.50's.  That obviously means the smaller engines were backed by 8.8's and the "big" 351's got 9" gears.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Bulldawg1081
In reply to this post by Rembrant
now on 4x4 trucks its a hit or miss on what rear axle it came with.. I had an 85 with an EFI 302 and an np435 4spd that had a factory 9" also... theres also a guy in my facebook  bullnose group that has an 86 short bed 4x4 with an efi 302 and a 4spd manual transmission with a factory 9" as well. I cant verify but Ive personally noticed that any v8 4x4 with a manual transmission came with a factory 9" though the 1986 model year. automatic 4x4's seem to follow the same guidelines as the 2wd trucks. Gary, this is another topic that needs researched so we can have facts.
1986 F-150 EFI 302 C6 2WD.
1980 F-100 300 C4 2WD soon to have a roller cam 351w,
1986 F-150 351W C6 4X4.
1986 F-150 351W C6 2WD *Parts truck*.
1985 E-150 351W C6 2WD  shaggin wagon.
1999 Mustang GT 4.6 T45 cruiser.
Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Bulldawg1081
In reply to this post by Gary Lewis
speaking of gear ratios, 3.50 (axle code 16) was the most common but there were several 83 to 86 9" equipped trucks that got the anemic 3.00 ratio (axle code 14) also. I had an 84 351 truck with 3.00's.
1986 F-150 EFI 302 C6 2WD.
1980 F-100 300 C4 2WD soon to have a roller cam 351w,
1986 F-150 351W C6 4X4.
1986 F-150 351W C6 2WD *Parts truck*.
1985 E-150 351W C6 2WD  shaggin wagon.
1999 Mustang GT 4.6 T45 cruiser.
Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Gary Lewis
Administrator
In reply to this post by Bulldawg1081
Yes, this needs to be documented, but I think I'm documented-out at present.  However, here's some info to dwell on:

For 1985:

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Dyn Blin
In reply to this post by Gary Lewis
Hmm.  A data point from my 82-  door sticker shows mine has a 3.5, but came from the factory with a 302.

Edit.  Makes sense cross referencing the trivia thread
Sonoma County,CA
1982 F150 Flareside XLS
NP435 4x4
351W Motorcraft 2150

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Bulldawg1081
but yours is an '82..  ALL 82's and older were 9" no matter the engine configuration, 1983 is when all that went out the window Lol
1986 F-150 EFI 302 C6 2WD.
1980 F-100 300 C4 2WD soon to have a roller cam 351w,
1986 F-150 351W C6 4X4.
1986 F-150 351W C6 2WD *Parts truck*.
1985 E-150 351W C6 2WD  shaggin wagon.
1999 Mustang GT 4.6 T45 cruiser.
Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Rembrant
In reply to this post by Rembrant
I came across this 8.8 Ford diff cover while doing my morning searches for Ford junk. I assume this would fit the pickups as well?

https://www.kijiji.ca/v-view-details.html?adId=1395060944&requestSource=b



I've been interested in an aftermarket diff cover...but it's pretty far down the priority list at the moment. The aftermarket Trickflow and B&M covers look pretty cool.
1994 F150 4x2 Flareside. 5.0 w/MAF, 4R70W, stock.
1984 F150 4X2 Flareside. Mild 302 w/ 5spd. Sold.
1980 F150 4X4 Flareside. 300i6 w/ 5spd. Sold in 2021.
1980 F100 4X2 Flareside. 351w/2bbl w/NP435. Sold in 1995

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Ford F834
Administrator
In reply to this post by Bulldawg1081
Bulldawg1081 wrote
speaking of gear ratios, 3.50 (axle code 16) was the most common but there were several 83 to 86 9" equipped trucks that got the anemic 3.00 ratio (axle code 14) also. I had an 84 351 truck with 3.00's.
I have 3.00’s in my truck (axle donor was a ‘82 F150 straight six). I like them even with the tall 31.72” tires, but I have the diesel ratio T19 and it drives more like a 4.10 ratio truck with an overdrive.
SHORT BED 4-DOOR DIESEL: 1986 F350 4x4 under construction-- 7.3 IDIT ZF5+GVOD

STRAIGHT SIX 4X4: 1981 F150 2wd to 4x4-- 300 I6 close ratio diesel T19, hydroboost brakes, Saginaw steering

BIG F: 1995 F-Superduty under construction— converting to 6.9L IDI diesel ZF5+DNE2
Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Gary Lewis
Administrator
In reply to this post by Rembrant
I think if it fits any 8.8 it'll fit the pickups.

As for the Trickflow on a 10.25", is this what you mean?  That's on Big Blue.  

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Steve83
Banned User
In reply to this post by Gary Lewis
Gary Lewis wrote
I won't say they couldn't have had a 9" in an '87.
I will.  All '87s 1/2-tons had RABS (RABS-1), and the 9" was never manufactured with an ABS sensor.  So it couldn't have been factory-installed in an '87 truck.  It would have to have been swapped in.
Gary Lewis wrote
...Ford didn't throw anything away when it would bolt right in.
Yes, they threw away a few things, but they didn't have many things manufactured that weren't needed.  So when they were winding-down production on '86 models, they also wound-down their orders for 9" axles simultaneously.
Gary Lewis wrote
I think if it fits any 8.8 it'll fit the pickups.
Yep - even an IRS 8.8" cover.

Reply | Threaded
Open this post in threaded view
|

Re: Rear differential questions 9" vs 8.8

Rembrant
In reply to this post by Rembrant
Quick question on the 8.8 rear diff...or any factory rear diff for that matter:
I was cleaning mine up today since I had it up on the bench...removing brake lines, etc. There was a hose on the vent...maybe 15-18" long...I didn't measure it. It was laying so that the open end was up around the driver's side brake wheel cylinder. Anyway...was there ever a little vent cap or anything on that end of the vent hose? Or was it just left open from the factory?

Sorry, I forgot to take pics...
1994 F150 4x2 Flareside. 5.0 w/MAF, 4R70W, stock.
1984 F150 4X2 Flareside. Mild 302 w/ 5spd. Sold.
1980 F150 4X4 Flareside. 300i6 w/ 5spd. Sold in 2021.
1980 F100 4X2 Flareside. 351w/2bbl w/NP435. Sold in 1995

123