Speedo bounce
Thread Starter
|
Junior User
Joined: Mar 2005
Posts: 61
Likes: 0
From: Florida
Speedo bounce
Hey guys, hoping to join you as a Bronco owner soon. Looking at a 95 EB that seems in good shape for the age. The only thing I've found that seems strange is around 50mph the speedometer starts to bounce. Is this as simple as a bad cable or a sign of bigger problems?
Thanks!!
Thanks!!
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
The speedometer is electronic, no cable. The most likely cause is a "gunked up" or faulty Vehicle Speed Sensor (VSS) on the rear axle. Other common causes are worn carrier bearings, missing teeth on the tone ring or a faulty PSOM (It's an electronic board mounted behind the speedometer). Every once in a while it turns out to be a faulty speedometer.
It's a crap shoot if it is something simple or a much bigger problem such as a rear axle that needs to be rebuilt.
It's a crap shoot if it is something simple or a much bigger problem such as a rear axle that needs to be rebuilt.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
The fast way to get an insider view of pending issues is removing the VSS on top of the rear axle. If it is really gunked up or chewed up you know there is definitely an issue with the rear axle. A small amount of debris stuck to it is normal.
The best way to know 100% what is going on is to remove the rear axle cover. Take a look at the lube for signs of bearing particles, smell it to see if it burn. If there are large chucks of metal that is another bad sign. Any play in the carrier is also a bad sign. Missing teeth on the ring/pinion or spider gears is another bad omen.
The last 8.8" rear axle I rebuilt cost about $400 in parts. I took the opportunity to swap from a 2.73 to 3.73 ring and pinion. I replaced all the bearings/races and seals. I also rebuilt the factory Trac-loc limited-slip clutches. I was lucky the axles themselves were in good shape. If you cannot do the work yourself I would double that price, then add a few more for inflation. It has been a few years since I did that rebuild.
The other option is to source a replacement from a salvage yard. The caveat to that is many of those have as many miles or more than what you already have. This is another reason why I rebuilt mine instead of swapping in a used assembly.
The best way to know 100% what is going on is to remove the rear axle cover. Take a look at the lube for signs of bearing particles, smell it to see if it burn. If there are large chucks of metal that is another bad sign. Any play in the carrier is also a bad sign. Missing teeth on the ring/pinion or spider gears is another bad omen.
The last 8.8" rear axle I rebuilt cost about $400 in parts. I took the opportunity to swap from a 2.73 to 3.73 ring and pinion. I replaced all the bearings/races and seals. I also rebuilt the factory Trac-loc limited-slip clutches. I was lucky the axles themselves were in good shape. If you cannot do the work yourself I would double that price, then add a few more for inflation. It has been a few years since I did that rebuild.
The other option is to source a replacement from a salvage yard. The caveat to that is many of those have as many miles or more than what you already have. This is another reason why I rebuilt mine instead of swapping in a used assembly.
Thread
Thread Starter
Forum
Replies
Last Post
DCGuillory
1968-Present E-Series Van/Cutaway/Chassis
2
Aug 6, 2017 05:06 PM
