Does anyone have any idea on how to tighten up a 8.8 rear-end on a 1990 F-150 4x4. It has 208000 miles on it and just now showing slack, but the rest of the truck is still going strong.
I plan on converting it to a older style Ford rear-end next winter or as soon as I can find a third member with a 3.55 ratio.
Any info would be greatly appreciated. thanx.

 

Typically, slack is from worn parts inside the differential unit itself such as spider gears, pins, and the splines on the axle shafts. None of this can be adjusted, only replaced. The backlash between ring and pinion itself can be adjusted, but it usually is not a major contributor to the total slop between driveline and wheels. If the ring and pinion are that sloppy, then they are probably wiped-out anyway.

 

Thanks. Looks like I'll have to switch over to a third member sooner than expected, not looking forward to it but its something I have to do. Been hearing some bad things about the 8.8 never owned on until now, always been older style from the mid '60s to late '70s.
Want to put little stiffer springs in anyway, what an excuse to go to the local salvage yard.
Again Thanks.

 

>I plan on converting it to a older style Ford rear-end next
>winter or as soon as I can find a third member with a 3.55
>ratio.

Well the "style" I think you're refering to is the 9" but finding one with a 3.55 will be next to impossible in a junk yard. I have found aftermarket companies that manufacture a 3.55 ring and pinion set for the 9", so if you have a good third memeber and the know-how or plan on spending some money to get a good place to build you up the third member you can get the 3.55 ratio.

If you are set on a 9" out of a junk yard, the closest you'll find will be a 3.50 ratio. Since you have a '90 then you have the Dana 44-IFS front end with a 3.54 ratio. The 3.50 9" will work just fine.

-Kerry

 

What's the best way to identify a Ford 9"? Will the tag help you out or do you have to have it apart and do some measuring? Never really messed with rear-ends too much, my dad had some old cars out behind our house and if I ever had one go out I'd roll a car over and take the rear-end out for my car.

Any suggestions are appreciated.

Leonard Bode

1990 F-150 4x4 302 Automatic
1986 F-250 4x4 400 Automatic
1955 Dodge W-100 4x4 360 Auto (Mud running project)

 

I'll assume you mean the ratio and not the fact it's a 9". If the rear end has never had someone swap out the ring and pinion for a different gear ratio then you can check the tag. It's hard to tell what you get if you get it from the junk yard though. I'd feel better about tearing one down and making sure I had a good one (no cracks or hidden flaws) before putting into your rig. Less headache later. You have also said that you want to put a 3.55 in it. That will mean it will have be disassembled.

Hope you are getting what you needed

-Kerry

 

Thanks, I have a friend who has some Ford pick-ups, 2 and 4 wheel drive, I'll go up there and see what he has under them they range from 1968 to 1979. Thanks again for the info.

Leonard Bode
1990 F-150 4x4 with 208000 and still going strong
1986 F-250 4x4 with 150000 and still pulling strong