98 ram1500 brake & abs dash lights on

[shafedog53]

start my truck the other morning and the brake and abs dash lights dont shut off as they usually do. shut off the truck and wait a few minutes, start it again, same thing. well i had to get to work and everything seemed to be working the same as before. drove fine to work. on the way home from work, the speedometer would only work if i was above 20 mph. nothing untill i hit twenty and then it worked normally untill i slowed below 20, where it slammed to the bottom at the 20. No idea whats going on. Buddy of mine said that it might just be bad brakes, but that was before the speedometer issue. Now the scary part is that i didnt know the truck had abs, it has never worked. ive locked my brakes in the snow and never had any abs kick in. and now the light is on? any ideas? on any part of my ever growing problem? THANKS

Justin

[crazys182003]

Alright the most common areas for the problem you are describing are your speed sensors. They do go bad pretty easily and are also easy to repalce. There are two of them One on top of your rear pumpkin and one on your tranny. Most likely its the one on your pumpkin that went bad. It is a dealer part for about $50 I believe. It is one bolt that can be undone with a socket and then one electrical plug also. Tyipical thing to go. When you get them repalced your lights should go out a few seconds after starting and stay out. BUT If your abs has never worked then it might be even more than a sensor gone bad. It could be your abs module or the electrical wires going from your module back to your sensor. But replace the sensor first then check it out.

[shafedog53]

hey went to autozone to buy the speed sensor for the rear diff... needs to be rewired. do you know if the dealer part has to be rewired or if it fits the current wiring harness?

[crazys182003]

the dealer part is not a rewire its just an unplug replug thing.the PN should be the same as my PN b/c I have a 2nd generation so the PN is 56028187AE. Mine is listed as being a sensor - wheel speed with a price of $36.60 but that was back in Aug. of last year.

[Leadhead]

I have a '98.5 and had/have a similar problem. The ABS and brake lights have been on for quite some time, but the speedometer started going whacko last Friday. Replaced the sensor on the pumpkin and it fixed the speedo problem. Also, the next morning the ABS and brake lights appeared to be fixed as well, but later in the day they came back on. It's odd because they're off when I start the truck in the morning but both are on by the time I get to work (30 mile trip). Any ideas?

[crazys182003]

during your trip to work do you travel over 55 mph? If so what might be happening is what happened with mine. My clutch packs in my rear end (Limited slip only) broke into pieces and were rolling around for awhile inside. The pieces broke of a piece of my Tone wheel which is what ended up throwing my abs light. The sensor counts the number of teeth on the tone wheel and if there is one missing after about 55 mph it will get confused and throw a code. My suggestion would be to open up your rear end and take a look around for broken chunks. But thats if you have limited slip. Make sure you have gear oil on hand along with rtv sealant and some additive for the oil.

[Leadhead]

As a matter of fact, yes, I drive between 60 and 65 a good part of the way. After getting off work tonight, the lights were off again. I don't think I went over 55mph on my way home, and as I recall, the lights never came on this evening so you may be right. Guess I'll have to pull the diff cover off and take a look at things. How much are those clutch packs?
The dealer paperwork state that this truck has the "anti-spin" differential, but it drags the tires simply backing up and turning, or even when driving forward and turning sharply such as in a parking lot. It feels a bit more than just limited slip, almost like it's posi-trac. What exactly does Dodge mean by "anti-spin"? Do they make both types?

[crazys182003]

well antispin is the same as tracloc which is the same as a posi. Its all in the language people talk. If it is not working properly then you aill need new clutch packs pretty much a guarantee. Now as far as what you do theres two options basically. You can have someone rebuild your rearend and that will take care of it or you can search ebay and find a complete posi unit which just requires install. When I had the problem I had to rebuild my entire rear end b/c when my clutch packs broke they also chipped my tone wheel and a few other things. Until I was done I think my entire cost was around 1200 or so. When you do pull the cover make sure to check everything out good. Check the gears for any wear and the tone wheel which is on the left for any missing teeth. Heres a link to a current ebay listing for the unit. The price is what I have seen them go for before and is pretty average.
http://cgi.ebay.com/ebaymotors/TRAC-...spagenameZWD1V

[Leadhead]

Thanks for the fast, helpful responses!
Maybe I misunderstood. When you said clutch pack, I assumed you meant some sort of a unit dedicated to the ABS system, not the diff itself. My diff seems to be working fine, but when removing the inspection cover, how can a person tell for sure it needs replaced? Is it really that difficult of a job to do yourself? I'm no pro, but I can get around with tools when need arises, plus, my buddy is a pretty good mechanic.

[crazys182003]

I have a buddy that actually works at dodge and when my rear end needed rebuilt he said it is not really a do at home job. But from what I have seen on other forums you can do it yourself if you would decide to get that unit from ebay. When you remove the cover if you see chunks laying around you will know your clutch packs have gone bad. The clutch packs are on the passenger side of the posi unit and break off pretty common. When they break off they end up rolling around the diff causing problems. Usually from what I have seen the chunks are about the size of a quarter maybe a little smaller. Sometimes if the chunks are not rolling around they may be stuck to the magnet up on the speed sensor. Hes a thread on another forum that will help you. He went through the same problems and ended up needing to rebuild his rear also due to the broken clutch packs.
http://www.dodgetalk.com/forums/show...t=clutch+packs

[Leadhead]

So, having never been inside one of these diffs before, what is the job of the clutch packs, to provide the posi or limited slip effect? If they are indeed broken, can I simply remove the pieces, clean the sucker out and put the cover back on and use it as an open diff until I can get it fixed?

[crazys182003]

Yes the clutch packs basically make the posi unit work properly. As far as cleaning it out and using as an open diff I am not sure. I personally would be a little weary of doing so b/c maybe not all the clutch pieces are broken there might still be some attached and you may not be able to pull them out easily. The only major problem with leaving the chunks in there is they bang around on your gears and chew them up and also they chew up the inside of your housing. My housing till I caught the problem was ground into about 1/8". Now if I had elft it go and it did worse then I mighta needed an entire new axle instead of just a rebuild. But mine was making a whining sound and it was awful. It kinda sounds like a high pitched fingers on the chalk board thing if its chewing up your housing. If you can't afford to repair it now and its not whining you might be ok with just cleaning out the chunks and using it as an open diff. You just need to make sure to keep an ear out and if it starts making noise then you need to open it back up and check it out again or get it repaired then for sure.

[Leadhead]

Well, my buddy and I took the cover off today and found a few shavings, but mostly just the normal "powdered" steel that accumulates on the magnet. There didn't seem to be any large chunks, so the clutch packs appear to be intact. We cleaned it all out, drove it to town (30 or 40 miles total) then drained it again and filled it back up. There was one shaving stuck to the sensor, so we cleaned it up and put it back in and things are normal again for now. We plan to run it for a couple of days then pull the cover and drain it once again. The truck has 210,000 miles and I don't know the mechanical history on it since I've only owned it for a couple of months. Hopefully it'll work fine from now on.

[crazys182003]

Well thats good to hear then. Maybe the shavings on the sensor were causing your lights to be thrown. Hopefully it was a nice easy fix for you just regular maintenance required.

[Leadhead]

Well, back to the same ole story. Cleaned and flushed the diff, removed the sensor and cleaned off one shaving from it, reassembled everything and it was back to normal. Next day, dead speedometer part of the time but would jump when hitting bumps in the road. Next day, works a little better but still wavers all over the place. Gonna pull the sensor again to see if there's another rogue piece of metal stuck to it.
The other idea I had is that maybe the unit is defective. Does anyone know the resistance value this sensor should show?