Speedometer going haywire

[Izzmo]

I'm at work now and as I was coming back right when I pulled into our parking lot the speedo was going up and down really fast until I let off the gas and then it just dropped to zero.

This has happened twice. The tranny sometimes acts weird when in this condition. The first time the tranny operated fine, but this time it went straight into neutral until I let off the gas a bit.

What could be the problem here? It's obviously not the gauge cluster itself.

ABS Module?

 

[Ict_Lx]

That's where I would start. My 98' did something similar when the ABS module was on the way out. Did your O/D light flash? Not sure on the actual troubleshooting procedure. Hopefully someone else can chime in.

 

[venom]

I'm at work now and as I was coming back right when I pulled into our parking lot the speedo was going up and down really fast until I let off the gas and then it just dropped to zero.

This has happened twice. The tranny sometimes acts weird when in this condition. The first time the tranny operated fine, but this time it went straight into neutral until I let off the gas a bit.

What could be the problem here? It's obviously not the gauge cluster itself.

ABS Module?

Dollars to doughnuts the problem will go away with a replacement ABS module.... This is somewhat validated by the fact that the ATX is going stupid too. The speed input to the computer comes entirely from the ABS.

May not hurt to check your battery / charging system voltage first however.

ABS modules are Gen 3 SHO specific, but not model year specific no matter what Ford or someone tells you. Find a boneyard with one and you should be good to go. If you get lucky you can remove the 5 Torx bolts (there is a big one in the middle of the module) that hold the computer to the pump assembly and not have to bleed the brakes, but it is a knuckle buster down in there. If getting a module from the boneyard, get the screws that hold it on incase you have to drill one out (I love rust). It may be easiest to get the module and pump assembly from the boneyard, that way you can see everything for dis assembly first.

 

[Izzmo]

Where is the module located?

 

[St Louis SHO]

Under the battery tray

 

[venom]

Where is the module located?

If you look in front of the battery and down you will see the connector going to the top of the ABS module, with a 10mm captive bolt in the middle of the connector.....

You'll want a drink before you start probably

Yeah it pretty much sucks... A ratchet wrench that can use a torx driver to pull the module is your friend...

 

[LJRuddy]

Nick, when you come over here Friday to get your parts, I can probably snag my ABS module as well. :wave:

 

[Izzmo]

Sounds like fun.. damn.

Sounds good Liberty.

 

[SHOZ123]

I changed mine from the bottom.

FWIW, I disconnected all the lines, bending the two from the MC up so as not to drain the MC. Then there are three nuts that hold the entire pump/module on. Take the whole thing out.

I did not have any problem with air in the lines but this is what I did afterward. Drove on a gravel road and locked up the brakes about 10 times at ~30 mph to activate the ABS. Then came home and bleed the brakes normally making sure to flush the entire system.

 

[LJRuddy]

What size torx drivers are required? I am getting ready to pull this out for Nick and I want to make sure I have the correct tools seeing that my 98 parts car is 35 minutes away. :wave:

 

[venom]

What size torx drivers are required? I am getting ready to pull this out for Nick and I want to make sure I have the correct tools seeing that my 98 parts car is 35 minutes away. :wave:

The 4 small ones I believe are T-20's. If it really is a parts car then cut the lines and remove the whole assembly, pump and module. The bigger Torx (in the middle of the module surrounded by the rubber "grommet" that is a mounting point is more like a T-40 or so but that is a total guess.

 

[Izzmo]

We ended up not removing it. Hopefully this doesn't happen too often again. I really don't have time to change this shit out right now.

Thanks for all the information guys.

 

[SHOZ123]

Mine had the speedo just start dropping out occasionally. Then it failed completely and the tranny got really stupid. Starting out in 2nd and no TC lockup at all.

 

[venom]

We ended up not removing it. Hopefully this doesn't happen too often again. I really don't have time to change this shit out right now.

Thanks for all the information guys.

Good luck with that.

I chased intermittent aBS problems for about 6 months before the speedo dropouts and tranny stupidity would happen 5 times in less than that many miles. Key off and restart would fix it for a bit.

At the very least I would acquire a module to have around.

 

[Izzmo]

Yeah, I think I'll do that.

Question: Is the ABS easiest to change from the top or bottom? Also, to make it easier, should anything else other than the battery tray be removed?

 

[venom]

Yeah, I think I'll do that.

Question: Is the ABS easiest to change from the top or bottom? Also, to make it easier, should anything else other than the battery tray be removed?

To go up or down.... Usually a easy question...

I think the visibility you will have from the top will allow you better luck.

Remove the battery tray and battery bracket. for best access.

 

[Izzmo]

Remove the battery tray and battery bracket. for best access.

Easier said than done! I will try my best.

 

[venom]

Easier said than done! I will try my best.

They remove fairly easily.... Reinstalling the one bolt on the bracket is a total PITA.... I have heard of people cutting a chunk out of the battery bracket so they can see the upper bolt.

 

[shoteen95]

Mine had the speedo just start dropping out occasionally. Then it failed completely and the tranny got really stupid. Starting out in 2nd and no TC lockup at all.

This happened to me once when I drove through a huge pool of standing water after a heavy downstorm. Dead speado, no TC. Didn't know it was the ABS module getting soaked.

 

[Ict_Lx]

This happened to me once when I drove through a huge pool of standing water after a heavy downstorm. Dead speado, no TC. Didn't know it was the ABS module getting soaked.

That happened to my 98' after an underbody wash at the corner carwash place. I had just purchased the car and didn't now that the front splash guard wasn't there. If you're taking the battery tray out, why not just put the battery in the trunk? If I had been thinking, that's what I would have done. That bracket is a huge PITA to get back on.