Lightning w/Viper spec t56 need speedo help

[SVT-BansheeMan]

I have a lightning with a viper spec t56 from a gen 2 dodge viper.

I can't get the speed sensor to work and make my trucks stock speedo read the speed I'm going. The dodge unit has 3 wires from it and the terminators use only a two wire speed pick up.

Has anyone ever put a viper trans in a cobra. I need to know how to make it work. I'm calling tremec Monday but i figure asking here was worth a shot. Thanks!

 

[SVT-BansheeMan]

only and final bump.

 

[Quagmire]

Well they both should be hall effect sensors to my knowledge. So 2 wires for cobra, means its a standard unpowered gate meaning it open and closes letting voltage through. The 3 wire one means it is powered. Mean there's a 12v power, signal and ground. So if you hook up the 12 feed to one of the two wires, and then the 2nd goes to the signal side of the sensor, then you would have to make a ground for the 3 wire, then it should work correctly. But you do not know the type and where the ref point for the hall effect sensor is. So you speeds could be off. The 12v feed should come from the ecm on of the vehicle side is 12 the other is the signal, but you more than likely need to ground the sensor still. Pm if you don't understand ill draw you a diagram

 

[Quagmire]

Here i did it anyways, all you have to do is find which wire are which. I would turn on the car and read voltages from the con to find the power. then the other one is the signal on the cobra con. Next gotta either find a wiring diagram for the sensor or test the gate and figure it out.



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[SVT-BansheeMan]

Quagmire, thank you!

I will try to get a diagram from Dodge to see which wires are which from the dodge unit. There's a 3 and i believe 2 are the same color.

 

[Quagmire]

Ya np, If you cant get a diagram i can walk you through how to test it and figure it out. That is always a bit risky though, those damn hall effects don't like to be powered wrong. What i would guess is the two are the same color are power and signal, the other is ground.

 

[SVT-BansheeMan]

I have a buddy who works for dodge. He is going to get a color/function diagram for me. My darn multimeter decided it was going to break today. To figure.

 

[SVT-BansheeMan]

It isnt working for me Quagmire.

From my buddy who works at dodge. He said speaking in terms of the viper side of the transmission....

purple with white is 5v supply
black with light blue is ground
white with orange is speed sensor

I cut the plug off the viper side so i have no idea which wire is which. Coming off the viper spec t56 all the wires are black. Middle is black with gray stripe. Middle has to be ground because the middle plug on the viper harness i have which still have the plug is blue/light blue. So the ground is for sure right.

I tried the other two wires on the ford speedo pick up side.

Ford speedo pick up wires are:
red/black stripe
green/white stripe

I tried both and it doesnt move the speedo. Perhaps i need to disregard one because it isnt a 5v source.

I know my ground is good because i tapped into the ground for my reverse lockout. It's wired to my brake lights. It works fine.

Another thing. If the dodge diagram says 5v source and my EMC sends 12v. I will have to alter that. Does the cobra ECM send 12. If so, did you have to alter that with a regulator?

 

[Quagmire]

Sorry was at a conference in DC all weekend.
I was worried about this.

First you need to check the sensor and see if it works. Sometimes they get really finicky and blow up with the wrong wiring. To do that find a 5v source and a ground to hook to the viper side then hook the the signal to a volt meter. If the hall effect sensor is normal close it should see 5v all the time until it comes across it magnet and opens to see 0v. Now if it is normally open it is the opposite. Now here is the problem what does the cobra ecm want to see, my guess it is open cus it is two wires..So hook it up find out what it says not moving then spin the tranny and see what it reads.

If you can get a signal and find out if its normally closed or open then we getting somewhere. Most sensors can read between 5-9v or 5-15v, but since the ecm sends 12vs it is expecting 12v back, it really needs the ecm power supply.
If you have the lightening cluster how does that effect the cobra ecm? Do you have a xcal 2 so you can pull the vehicle speed right from the ecm? My question does the ecm receive the signal and the cluster just not get it?

These guys might be able to help you more than me, since they deal with it everyday.
Welcome to D&D Performance - Contact Us

First call DD and see what they say, you might be able to switch sensor out. PM if you need anything else.

 

[SVT-BansheeMan]

If you have the lightening cluster how does that effect the cobra ecm?

I dont understand this question. Im using a lightning cluster and ECM because it's a Lightning. Nothing i have on the truck has to do with a terminator. I just posted hear because i figured someone has done this

 

[Jimmysidecarr]

Moved and bumped.

 

[oilwell1415]

Silly idea. Shove a Termi speed sensor and appropriate ring in the trans?

 

[02SILVERBULLET]

Silly idea. Shove a Termi speed sensor and appropriate ring in the trans?

+1?
The two transmissions are the same case supposedly with different front plates and tail housings, and belhousing of course. but the main case should be the same. have you checked to see if the cobra speed sensor will swap in?

 

[02SILVERBULLET]

I had planned on using the same setup as you as i want the .5 od sixth gear. versus the ford spec .63 or whatever...
call tremec, as my plan was to order a t56 magnum from them in hopes of being able to get the gear set i want with the viper front cover and the ford type rear housing. but i have not got that far into it as that project is kinda back burner for me.

 

[SVT-BansheeMan]

+1?
The two transmissions are the same case supposedly with different front plates and tail housings, and belhousing of course. but the main case should be the same. have you checked to see if the cobra speed sensor will swap in?

Didnt know this thread was moved, no wonder i couldnt find it. I put it in the terminator section because terminator/mustang owners have done this and made it work. I posted this on Lightning rodder and received NO help. But thanks for the bump, it worked:rockon:

Cobra speed sensor doesnt swap in. It is too big. I cut the plastic outside of it and put the guts of it in the hole and it fits. However, as luck would have it, it doesnt work.

I thought about using a terminator tail housing but then i would need a new drive shaft made. The rear spline is different. But the time i do that, i can just sell my viper spec t56 and buy a terminator one. I dont want that hassle. I hate dropping my trans under my carport on jack stands.

My truck is at a local performance shop and i asked them to figure it out. If they cant do it, ill call up d&d performance and have them walk me through it as my last resort.

I dont want to use any other trans atm. 6th at 70mph is 1500rpms. It's nice.

 

[castellscl]

Updates?