Rear differential questions 9" vs 8.8

[Bulldawg1081]

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!

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.

 

[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.

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.

[Gary Lewis]

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.

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:

[Dyn Blin]

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.

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

[Bulldawg1081]

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

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

[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.

[Ford F834]

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.

[Gary Lewis]

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.

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.

[Steve83]

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.

...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.

I think if it fits any 8.8 it'll fit the pickups.

Yep - even an IRS 8.8" cover.

https://supermotors.net/getfile/932346/thumbnail/diffcover.jpg

[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...