Need the help of the in the know. My speedometer is either jumping all over the place or it stabilizes at about 2x the speed I'm traveling. That's the symptom. I've been told (right or wrong) it's probably the sensor on the transmission has gone bad. That seems like an easy fix so I looked up the part. The local stealership wants $450.00 for the part they told me I need and wouldn't even tell me the part number. That option is out. I looked the part up on the usually dependable part sites and found the part for around $160. The part number I came up with is 8318112020 . Some sites show this part with a plastic gear on the end of it and others do not. None of the sites show a location on the transmission. I thought it was the sensor on the passenger side of the tranny but was told otherwise. Any experience like mine? Any help? Much appreciated. You folks are great..............Thank you,
VIN# JT4VN13G2P5110695

 

Manual Transmission? The part number you give is for a Manual. RockAuto has that part for about $75.00. Me, I'd pull out the one you have and compare it the very good photos on the RockAuto site. The various versions of the speed sensor, fortunately, are not easy to confuse with each other.

RockAuto shows their part with the plastic gear; when I replaced mine (with a genuine Toyota part; RockAuto didn't exist then), the part didn't come with the gear. I reused the original. Of course, if your gear is messed up, the sensor is probably not the problem anyway.

The sensor (VSS1) is mounted on the back of the transfer case; VSS2 is mounted on the front of the transfer case. Why? The transfer case has two speeds. For the speedometer, you want the output speed. For shifting the transmission, you want the speed of the transmission before the transfer case.

 

Great info. As soon as I can get on it I'll report back. Thank you very much,

 

Awhile back you answered a post of mine about the speed sensor. As I understand you're telling me there are 2? One for the transmission and one for the speedometer. Which one am I looking at in the picture here? Appreciate the input. Cheers......



If my speedometer is jumping around is this a good start to fixing that? Thanks.......

 

Is that a special anti-rust undercoating you have covering your transfer case?

I'm going to guess that once you get through that "coating," you'll find something that looks like this:

[From RockAuto]
This is the speed sensor for a manual. Me, for $75 I would replace it. You could start with just cleaning up the connector and see if that helps, but that "coating" is likely to return.

Note that the new part doesn't appear to include the gear and shaft. So remove yours first to be sure the gear is okay.

 

Thanks much for taking the time to help me out. I'm going to clean all that up before I pull the sensor. A lot of that is just oil from quite a few leaks that I have fixed. The only symptom this effects is my speedometer is erratic and usually shows 2x the speed .So to be clear the sensor I'm showing is the one that controls the speedometer? The truck seems to shift fine. It is a 5 speed manual 4x4. I've replaced and flushed and rebuilt it seems half the truck. Only a small handful of issues to go. Again thank you, I hope that fixes the speedometer but it's not effecting the driving. I've got a 22, 42, and 43 code. The 22 is the water temp sensor I think. (located on the rear of the engine near the firewall). 42 is the speed sensor. 43 is some type of ignition code. 33 year old trucks need some TLC.

 

Here are the diagnostic codes. Not worth your time to guess about them.
http://web.archive.org/web/201211190...85diagnosi.pdf
I have an automatic, so my sensor looks a little different from outside. So while I can't say for sure yours is VSS1, it sure looks like the photo.
As you've already learned, your truck is not built out of legos. You might have an erratic speedometer due to a bad speed signal, but your actual problem might be wiring, or the cluster, rather than the sender. (In my case, I used a signal generator to input a fake signal at the sensor; the speedometer responded correctly so I knew it was the sender.) For you, it would be cheaper to spend $75 on the replacement part than buying a signal generator, but tools are tools!

The speed sensor has no effect on manual shifting (that's what your right arm is for). It can effect engine performance. In your case, if you're missing the temp sensor signal (code 22), that will definitely affect the engine.

 

An update on the speed sensor. Parts Geek sent me a sensor for an automatic transmission. As soon as I removed the original I knew their part would not work. Their return process is a joke. By the time I pay to ship it back and pay a 20% re-stocking fee it's not worth my time. I will never order from them again. Lousy customer service and return policies. The two visual differences are the connector on a manual sensor comes straight out the end. On the automatic it's on a right angle. The gear on the original sensor is much larger than the gear on the automatic. The gear looks like it would be easy to swap from one to the other. The connector (female) is held on by three screws and looks like it could also be traded. Maybe those two things are the only difference? I might give it a shot and laugh if it's that simple.
Bottom Line Parts Geek BITES................

 

My guess is the capacitors on the speedometer board are leaking and corroding the board. Take apart the dash, take out the instrument cluster and then carefully remove the speedo from the cluster to inspect the board. My speedometer was stuck at zero. I replaced the capacitors and carefully touched up the board traces with a silver conductive pen. Has worked perfectly ever since.