sc1jzgte

I am trying to understand what the rear speed sensor is. I am not talking about the speedometer driven gear. Please take a look at the diagram below and study that there are 3 major attachments to the tranny.

1.Back up light switch
2.Speedometer driven gear
3.Rear speed sensor

My conclusion to this is
1. Obviously for the reverse lights
2. Mainly for the MPH reading on the spedometer in the cluster?
3. ???, wild guess..cruise control,???

My issue is I have a gaping whole where #3 is. and i cant start my car with out that hole plugged because i cant put the fluid in with a hole in tranny. That part is $160, so does anybody know:

What it does if its not used and just plugged?
Are there alternate parts to use I can look for?

Also since we are on this, the speedometer driven gear, is that the part that Craaazy meant he made the w58 one work? and 2jzlex said he had a solution?

Then the reverse light.. i have an auto 1jz ecu... i read its just supposed to plug and play? it didnt for my w58, i will find out on this one i guess.

http://www.cygnusx1.net/Supra/Librar...ection=MT&P=49

Thanks

2jzlex

iTrader: (3)

The VSS on the passenger side of the tail end of the transmission is the speedo sensor. The problem with swapping R154 transmissions is that most of them are out of an MKIII which has a cable driven speedometer sensor. There have been people that claimed the MKIII came with an electronic speed sensor. This is NOT true. It DID have an electric sensor, but it is not the one that we need for the speedo, it was for the ecu and other various things. Trust me on this, I have researched, looked, started threads, etc. there wasn't a model made w/ electric speedo, at least in the U.S.

The harness has a 3 prong connector that is electric in the SC and MKIV supra. Some people use the VSS from the W58 in the SC 5 speed and swap it over, or use the one from the auto transmission, I believe both work if you make a bracket and switch the plastic gear drive on the end. Do a bit more research to confirm that. At first this was the route I was going to go with, but the sensor is $260 from Lexus, and the same from Toyota after I crossed the numbers. I would still have to MAKE this one work w/ a bracket and what not. The one from the MKIV auto trans won't work as that is what I had, neither the clip or the rubber seal for the hole was right.

So the solution is this....
MKIII cable speedo sensor and bracket, it's like $40 w/ the bracket from Toyota.
And this...
http://www.marlincrawler.com/images/vss_all_1000.jpg

It converts the rotations to pulses and sends it out electronically. Problem solved for like $100 including shipping. If you can find a junk yard that is willing to part w/ the sensor, or if you can even find one, you'r one lucky guy.

Simply put, you dont need the rear speed sensor. Take it out and plug it with an expandle rubber plug from your local auto parts store.

Jon

sc1jzgte

So the electric sensor that the MK3 did come with for the ecu and such.. what physical one is that labeled in this diagram? can you give the name in the diagram so this is clear. (i think you mean rear speed sensor and you are saying that is not needed for our car)

The VSS on the passenger side is the speedo sensor? Can you clarify from the diagram which one that is? (I think you mean speedometer driven gear, in which you described the solution for that)

Speaking of that solution, i have the w58 already.. so all i need is a bracket? or i have the r154 also, so i can get that piece for 60 to make that work..

Please clarify and let me know if I am correct, thanks!

2jzlex

iTrader: (3)

Yes rear speed sensor, this goes to nothing now, get rid of it.

Correct, speedo driven gear.

I don't know for sure, try the 58 seeing as how you already have it. It might drop right in and work like a charm. If not, the best functioning/looking solution will probably be to go with the converter from Marlin Crawler. This way you can still use the gear driven sensor that was meant to be in there, and you can also reuse the bracket. All the sensor does is convert the rotations to electric pulses. Look at the picture and then look at the plug in your harness, just make sure they fit and there ya go. Good luck and let me know how it goes.

Jon

craaaazzy

iTrader: (4)

2.Speedometer driven gear - yes, this is the one i used the w58 sensor and had to make a bracket for. just got my gps back so i should be able to confirm mph shortly.

3.Rear speed sensor - mine did not have this as it was a 1jz r154...but i don't think you'll need it. the sc300 did not have a plug for this anyway.

sc1jzgte

great clarification on this situation guys, hope this helps the rest. Now does anybody have the part number for the plug used on the 1jz version of the R154, since the 1jz version doesnt have a rear speed sensor i want that plug... Blizzy?

craaaazzy

iTrader: (4)

call jeff at champion. he may be able to help you.

sc1jzgte

so late last night in the dark i crawled under and pulled out the r154 cable speedometer driven gear. And popped in my 92 sc300 w58 electronic one.

Also i measured the hole for my rear speed sensor that isnt needed.... i fit different sockets in it and a 12mm fits perfectly snug. I am going to take a short 12mm socket, weld a bracket on it and use some gasket seal and voila, plugged.

I was rushing but i concluded quickly that it fit in the hole "Perfectly" and the mounting bracket was the perfect distance for the whole.

BUT, the black plug piece is kind of in the way so i cant twist it to get the mount lined up with the whole..... it was very dark and uncomfortable so i was satisfied and left with that. when i get another chance i need to see what needs to be shaved where to get that to align with the hole

Craazy, you said you made a bracket and that it didnt plug the hole completely?? can you confirm that yours was different than mine in this pic?

As you can see the main difference is the Black plug piece. The mounts look the same, except the r154 mount is just a separate piece of metal, and once bolted in it overlappingly holds the speedo in place.

sc1jzgte

here is another angly, the diameter of the bulk part and the gear are the same.

2jzlex

iTrader: (3)

Hey 1jz,

I found out something interesting you might want to know. There is a 33 and a 35 toothed gear in between the W58 and the R154 models on the MKIII. It may or may not be the same with the SC 5 speed. The R154 is the 33, and the W58 is the 35. While you have them out, look em over and see if this is correct or not. It could have an affect on the speedo readout.

Jon

sc1jzgte

my R154 = 32 teeth, my 92' w58 = 33 teeth..... (many confirmed counts in dire desire to make the numbers both the same, unfortunately i am sure this is the proper tooth count)

also I put marker on the gears and rolled them on a paper next to eachother, the r154 can be seen to close the gap for its missing tooth.

Also the diameter is the same on these both 3cm, so if it has the same diameter but 1 less tooth then technically it wont line up perfectly (if one was bigger it could still work even if it had twice as many teeth, as long as the angles ratios etc matched up) Unless the one tooth is so minimal i cant measure the diff in diameter. It looks like that can be the case.

Well its easy to take in and out, so I am going to go with the w58 one, and test my mph, my mph was already off by a few mph due to bigger tires, so maybe this will fix it If its way off or something i will get the part from marlincrawler.

craaaazzy

iTrader: (4)

jon, sc1jzgte found the same thing i did. the early model w58's speed sensor gear is the same as the r154 (from a 1jz from my end) gear.

sc1jzgte, i believe what i meant was that the screw hole didn't line up because of the plug. the way i have it on mine is the plug goes towards the rear of the vehicle, that way the bracket i made would not touch it plug portion and would allow me to easily plug in the wiring harness.

sc1jzgte

looks like we double posted, have you driven your car yet and had a chance to match the mph?

sc1jzgte

by the way i want to add i have no idea what my r154 came from, i got it from a ford guy... it had not bellhousing and no rear speed sensor in it

craaaazzy

iTrader: (4)

i've driven it but have not verified by gps yet. just got my gps back from a friend who borrowed it. it didn't seem too off when i drove it. if u confirmed that it's a tooth difference, that's about a 3% difference in speed...so going 60mph would read 62 mph on speedometer but if u have a larger diameter tire, it may well offset that perfectly. i'm running tt rims and stock sized tires.

need to pick up my car to confirm speedo though and will probably do so this weekend.