Speed Sensor in 99 Ram

Hello again, my 99 Ram has a speedometer/odometer that now seems to only work when I go above 45-50mph. The check engine light was on, and a local garage told me it was a faulty speed sensor, probably in the rear. I have 2 questions, How can I locate the sensor and install a new one. Any tips?(I know I need a service manual :) ) Also, the mechanic said that if the speed sensor is gone it will hurt my tranny because "the speed sensor controls the shifting". Is this true in any way?
Thanks to everyone who has helped me in the past, I am definately learning:grinyes:

Leo
99 Ram Pickup 5.2

if the speed sensor is bad there must be a reason why check the sensor and then check ur rear . i have a 01 ram and had to bebuild my rear after the spider gears destoryed the whole diff.

Actually, if you drain and check your diff. lube for anything unusual (chunks of metal or shavings) and find nothing, you won't need to go any further on the inside.

I have a 98 and am getting ready to replace my sensor for the 3rd time (140k miles). I'm looking into aftermarket sensors because the mechanic I used to go to had told me that these trucks go through these pretty regularly.

The sensor is not to difficult to get to. It is on the top of the housing. I have searched the Gen. II manual I have and still haven't found any actual diagrams of it but have seen it in Chilton's at the parts store and it shouldn't be that much to change.

Hope this helps.

Thanks! Sorry to everyone for the duplicate post. I will try to check the rearend. So the sensor isn't located near the wheel? Also, is there any truth to the sensor damaging the transmission?

Guaranteed it's the sensor on the trans and not the diff. If it was the one on the diff you'd probably have no speed indication at any speed.

Guaranteed it's the sensor on the trans and not the diff. If it was the one on the diff you'd probably have no speed indication at any speed.


I'm not so sure about that. This is the exact same problem I had about 3 years ago and it was the rear sensor. This sensor is also responsible for the ABS signal and I have already had it replaced twice.

Unless the 99 and the 98 changed.

My two cents worth...if wrong you can send me my change back. :eek:

Thanks for all the info, can anyone tell me exactly where to find the sensors, or how to verify if they are bad?

Thanks again!

well the rear end sensor is right on top of the rear pumpkin. There is an electrical connection on top which is your sensor. I don't know how to verify it if its bad but its not really that expensive. When my ABS light and brake light came on awhile ago my sensor had a lot of metal on it then I opened it up and found chunks. Ended up with a rebuild.

I checked on another forum and there are 2 speed sensors one at your trans and one on the rear. The one on the rear controls low speeds and the one at the trans controls higher speeds. So I would definately toss in another sensor in your rear and it only costs about $40 at a dealer. BUT just get the part put it in yourself.

I checked on another forum and there are 2 speed sensors one at your trans and one on the rear. The one on the rear controls low speeds and the one at the trans controls higher speeds. So I would definately toss in another sensor in your rear and it only costs about $40 at a dealer. BUT just get the part put it in yourself.


Thanks for the help, I'll check it out.....

well the rear end sensor is right on top of the rear pumpkin. There is an electrical connection on top which is your sensor. I don't know how to verify it if its bad but its not really that expensive. When my ABS light and brake light came on awhile ago my sensor had a lot of metal on it then I opened it up and found chunks. Ended up with a rebuild.OH man, my truck was hit by a drunk while it was parked and I think it was pushed about 10 feet and now the ABS and brake light stay on. What does that mean? Bad sensor or bad diff. The truck seems to run fine, but there are some strange sounds coming from the rear brakes. I haven't been driving it, but It will go into the shop in the next week or so.

means new rearend basically. There is probably a broken tooth on your tone wheel on the inside of the pumpkin. The clutch packs probably also broke and are rolling around.

well for some reason it won't let me edit my post.......
I forgot I highly suggest you not drive your truck anymore. If you drive it you may end up needing an entire new rearend where as you might be able to save your carrier. I didn't know this when my light kept coming on. I got lucky and only ruined 1/8" of the inside of my pumpkin. I was able to reuse the carrier.

Just to follow up on my original post, can the speed sensor being bad actually harm the transmission? This is what I was told by a mechanic. He said the transmission is controlled by the speed sensor....
Thanks!

99 Ram 1500 4X4