Swap Ford 8.8 to 9

motoxscott

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It seems like I've talked to a million people about this but can't get a definitive answer, just theories. I've searched this board and others too.

What does it take to swap out a Ford 8.8 with a speed sensor in a '93 F-150 and swap in a Ford 9" ? I'm not the only person who has thought of this, someone has to have done it. This will be for a linked rear end.

What all is the speed sensor used for? I only need the speed sensor for the ABS system, speedometer and to make the computer happy. I will be installing a manual valvebody C6 so I don't need it to control the transmission. I will also be using the Ford Motorsports mass airflow conversion with the stick shift computer.

Sandy Cone said you could machine the rear end carrier to install the tone ring and then weld in a bung for the sensor.....but he has never done it. I dont really want to buy a complete trussed 9" and then screw it up.

H&M said autometer had something that went off the transmission to send a signal that would work, but when I called autometer they said they had nothing of the sort.

Currie said it can't be done.

Do I even need to worry about it and just not install it?

Any help would be great, as I know a lot of people on this board and others are looking for the same answer.

-Scott
 

RacerX

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Re: Swap Ford 8.8 to 9"

I have an 89 F150 and am in the process of putting a 9" in. To find out what it effects, I just unpluged it and drove around. Nothing happend. I also have a C-6. I can see that it might make a differance with having the E4OD being all electronically controlled. I had the AOD. So the only advice I can say is to unplug it and see how the truck drives.
 

Sites

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Re: Swap Ford 8.8 to 9\"

If you do try and disconnect the speed sensor and drive around, let me know what happens. Just before the build-up was started, I blew the fuse that goes to the speed sensor and the only problem I remember having was the speedo didn't work and shifting -- it would rev really high and then slam into gear. But other than that, it ran fine. If those end up being the only two problems, my solutions are,

Speedo: Run a mechanical autometer gauge (cable type) from the C6 or a GPS -- I am probably going to run GPS, but I don't know yet.

Shifting: Manual valve body.

For the ABS problems, I don't think it throws the check engine light, just the ABS light. Since you won't be using ABS, just pull out the ABS bulb in the dash :)

My transmission should be here either tomorrow or Wednesday, and we are hoping to be driving the truck the weekend of the 15th.

- Andy

94' Lightning Prerunner (in-progress)
 

CRAIG_HALL

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Re: Swap Ford 8.8 to 9\"

I JUST SWAPPED MY 8.8 OUT MY 97' RANGER FOR A 9". SO FAR THE ONLY PROBLOM IS THE ABS LIGHT IS ON. TRUCK ONLY HAD REAR ABS,IF YOU HAVE FRONT ALSO IT MIGHT NEED TO SENSE THE REAR ALSO NOT SURE. NO PROBLEMS WITH THE 9" IN A RANGER JUST NEED TO REMOVE DASH TO TAKE OUT THE BULB.

CRAIG
 

motoxscott

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Re: Swap Ford 8.8 to 9\"

A few weeks ago we disconnected the speed sensor from a manual 2000 4.0L Ranger. The brakes worked terrible. They would lock up under the lightest of pressure. The other odd thing is that it didnt shift as smooth. Since it's a manual, you wouldnt think that, but it did. As soon as we plugged it back it, it was smooth shifting.

What all is the speed sensor signal used for? Is it tied into fuel mapping, ignition curves ??

Maybe since it's a newer style ECM that is uses that signal for more things than the older versions.
 

NEWLINE_k2

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Re: Swap Ford 8.8 to 9\"

On my old ranger I dissconected the speed sensor and nothing happened, it drove the same as when it was plugged in. Now on my new 01' sporttrac i've yet to unplug the sensor, but I have pulled the ABS fuse and the rear brakes became real touchy, but only sometimes, other times normal, and other times you are locked up! I plan on putting a 9" in soon so i'm looking forward to what we come up with here.
By the way its a 4.0, w/5-speed auto, 8.8" in the rear.

newline-products.com
 

In_the_works

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Re: Swap Ford 8.8 to 9"

This may be a dumb question, but is the speed sensor at all related to the speed limiter that is stock on most fords? You know, that annoying device that regulates your speed when you get into higher mph (about 85 on my truck)? Either way, I've heard that it is a small task to remove it, anyone ever done this?

'96 F-150 4x4 ex cab
'02 Maico 250
 

Kritter

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Re: Swap Ford 8.8 to 9\"

IT is simple fix...there is one wire that tells the computer when you are in top gear and then when your RPS hit a certain point it kicks in a rev limiter. ON the 5 speeds it is as easy as unplugging the wire on teh snout of it...I did it and no side effects yet. or you can wire it through a switch so you can have it sometimes and then off when you need to get on the pipe. It gets scary going for a pass in mexico and having that stupid thing kick in! I dont have the sensor in the rear end either...pulled it out when I swapped in gears and posi and it made no difference either.

Kris
<A target="_blank" HREF=http://www.barneysprecision.com/fabproducts.htm> Fab Parts</A>
 

jeff

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Re: Swap Ford 8.8 to 9\"

deja vu' ?

I've replied to this same question probably five times in the last few years here in RDC. Each "how-to" gets shorter and shorter because the basic idea is so simple.

Pull the diff cover on the 8.8 and locate the tone ring. It is located next to the ring gear.

Locate the magnetic sensor that is almost but not quite touching that tone ring.

All that is needed to retain the system when converting to a 9" system are those two components... or if you are creative JUST the magnetic sensor.

You can attach that sensor to almost any rotating object that turns when the rear wheels turn... easiest being the driveshaft, axleshaft, or ring gear/diff. The computer can sense speed by monitoring how quickly the teeth on that tone ring pass the sensor. All the magnet does is turn on and off really fast as those teeth pass it. If you are worried you'll F up your new housing you could mount a similar setup on the driveshaft. You can calculate the number of teeth needed for the new tone ring by first determining how many RPMS the current tone ring is turning at a given speed... and then after figuring out how many RPMs the driveshaft spins at that same speed, the diameter and teeth needed for the new tone ring. This ain't tough stuff to figure out and it still pisses me off that Currie doesn't get on the ball with this. I went through the same thing with them a few years ago... and considering how easy it would be to offer a "retrofit kit" it's a dumb move on their part not offering one.

I used to have pictures of an 8.8 tone ring installed in a 9" 3rd member. They were hosted on RDC and I think Klaus deleted them as time wore on. The tone ring was attached near the ring gear, a hole was cut and a bung was welded into the 3rd member, and everything worked like the factory intended it to.

Things to remember... The nice thing about locating the sensor in the 3rd member is the protection it provides. Anything magnetic in the dirt will end up attached to the magnet. In most cases it's not enough to hamper the "signal" but if you don't somehow shield it the poor thing might get torn off should you decide to go off course.

The next time I'm stuck at home with a cold or flu I'll write a proper HOW-TO.

Aloha
 

hoeker

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Re: Swap Ford 8.8 to 9\"

good lookin pup.

Some are born great, some achieve greatness,
and some have greatness thrust upon them.
 

motoxscott

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Re: Swap Ford 8.8 to 9"

Here's a follow up to this.............

I just got off the phone with a Ford Racing Tech guy and he said that the speed sensor is only used for the electronic transmission, speedometer and the ABS module. (on a '93 F-150)

I will be installing a manual valvebody C6 and also the Ford mass airflow conversion, which is a modified mustang computer. The speed sensor is in no way tied to the engine managment. To solve the speedo promblem I can install a sender in the tail housing of the transmission and install an aftermarket speedo.

I'm just gonna go for it and see what happens and not even worry about the damn sensor.
 

curt

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Re: Swap Ford 8.8 to 9\"

Yeah, write up a how to with pictures, I'd really like to see what your talking about. I was contemplating ideas to get a speed sensor from the rear axle somehow to my data logger on our Toyota and just couldn't figure how to get the signal without building something likely to get ripped off in the dirt. Do all computerized or ABS 8.8's have this or only just a few vehicles, what to look for in a junkyard? Thx, Curt

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Beat98TJ

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Re: Swap Ford 8.8 to 9"

I just read this as I am getting ready to do this on a truck we are working with.

Jeff, did you ever do a detailed write up with pictures? If so do you have a link?

Is there anything new with this conversion? New kits, etc?

Thanks,
Frank
 

wolverine

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Re: Swap Ford 8.8 to 9"

I did this last summer for my 96 f150 when I converted to a custom 9inch. I used the tone ring and speed pickup from the stock 8.8. If the sensor was unhooked I had no speedo and the truck wouldn't shift.
I basically just mocked it up w/ the 3rd member and realized it wouldn't just automatically work but could with some effort. I did a little machining to the id of the tone ring and to the od of the ring gear. I have 4.88 gears w/ detroit locker. I think I machined a little off the od of the locker also. When finished the tone ring had a slight press fit over and onto the locker and ring gear w/ a few tack welds to the tone ring just because. I intended to copy the factory set up like it was in the 8.8 but had clearance issues w/ the tone ring and the 3rd member. That was the reason for the machining. The ring needed to be moved inward (closer to the centerline of the pinion gear) so it had the room it needed in the 3rd member. I then made a bung and mounted the sensor on the housing. This is a little tricky to get the proper location and gap between sensor and ring, so just take the time to get good measurements.
My truck works great, speedo works, shifts normal, and the brakes work normal. All you need is access to a lathe and take some measurements.
 

Beat98TJ

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Re: Swap Ford 8.8 to 9"

Well, I have access to a full machine shop, so I am not scared of a little machining.

Also I have found pictures of a vss conversion kit by California Pre Fun on the net.


(Borrowed from fullsizebronco.com)
 

Beat98TJ

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Update,

The California Pre Fun VSS kit only works on the Bronco 1356 originally with a yoke on the rear output. It is $300.
 

flyinbronco

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www.breaautoelectric.com/products/products1.htmlI've got a 94 Bronco that I swaped to a 9" rear from an 8.8. You send them your yoke or drive shaft flange off the transfer case or transmission for a 4x2 and they machine it to be the tone ring for the speed sensor. You simply remove the stock speed sensor from the old rear end and make a bracket to mount it next to the modified yoke. Worked well for me.
 
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