hey guys just finished installing my th400 behind my 6.0/ls3 into my gen 4 95z28 fbody. got the 98 red blue ls1 harness and p59 flex or whatever pcm to control everything. bought the harness from someone who had similar setup. wanting to hook my stock speedo up to work properly or close. im willing to go to the front or rear wheel sensor but i plan on changing front tires alot or racing. i also want to run the digital dakota thing that maye will work. im not sure which ppm my car is or where to start? i don't want to buy Dakota digital and have it not work r if the wheel sensor is easier id rather do easiest and cleanest route. my abs is gone and have a wilwood proprotinoing valve. if anyone has any info on this or has done it id appreciate the help. Ive searched and come up with different ways but some say Dakota digital is easiest but some say it doesn't work which leads me towards the wheel sensors. thanks guys

 

I do not know what type of vehicle, you are using or what type of speedometer it has.

GPS based speedometers are the most simple to set up/ use today.
I do not recommend using a wheel-speed sensor for speedometer usage.

There was a factory electronic vehicle-speed sensor produced for the THM400 at the end of their production...
But they are scarce and have a bad habit of collecting metal debris from inside the transmission.

You could easily use a cable type speedometer housing and gears in the THM400;
then get an adapter to convert the cable drive to electronic pick-up from Auto-meter of other companies.

Like this here:

 

Thanks for the reply. It’s a 1995 z28 fbody 4th gen. I swapped over to ls. It think they’re electric gauges. I don’t really want to take the tail shaft off or have to replace a reluctor inside since everything was just put in the car so I’m installing my shifter kickdown speedo and I’m off. Trying to get the easiest way for the stock one to work while driving. I know gps works but that’s annoying

 

Do you have a VSS in your THM400 transmission currently?

Or do you have a speedometer gear set/ housing in the transmission currently?

If you have the gear set (like most THM400 do) then get an adapter like the one I posted a photo of.
Most can be programmed for what ever pulse-rate the OEM speedometer requires.

 

If you do have a VSS... which one do you have?

 

sorry not sure I have the vss maybe I do? How can I tell? My trans is from an 60 impala I believe. What should I look for my trans just has the threaded plug on the rear of case can you text me for help? 6502189005 thanks

Kevin

 

The mechanical to electronic signal like what vortec is suggesting is what we recommend for customers trying to retain speedo function. like the said the factory VSS sensors are incredibly hard to come by in working order and you could easy buy a new mechanical to electrical signal converter for what some people sell the 30 year old used sensors for.

 

Either I need to...or someone needs to...start combining one of these https://www.ictbillet.com/billet-alu...turbo-400.html
with a hall effect sensor that threads in.

Easy to come by 40 tooth reluctors

 

if you have removed your ABS, I run my vss for speedo for the th400 with the abs signal off the front wheel hub. Your car will have that for sure. If you are retaining ABS, than you need to do what is being discussed above.

 

no as I stated in the post the abs has been deleted and I’m working on my proportioning valve and line lock system soon as well after this trans issue is fixed. So some recommend abs sensor and some don’t. I just want it to work and when I switch to drag tires I don’t have to change much lol. How do I know if my trans has the 40 tooth? Some say I have to swap them and I don’t want to do that unless trans is coming out again. I already forgot the filter had to k back, forgot converter bolts, had to go back, it’s getting old lol

 

Okay, from what you have said thus far...
I am assuming that you have one of these things:


Sticking out of the rear section of the case, on the Driver's side... looking like this:



Okay, so now you are going to get an adapter... that looks like this:


And install it on to the threads that are sticking out (like in the first 2 photos above).
It will look like this:



This is an adapter for a cable-driven speedometer to an electric speedometer.
You want to buy one of these adapters that is programmable, and can connect to the wiring for your current speedometer.

 

Yes that’s what mine looks like. you’re the man. The world needs more people like you around. Honestly. You answers all my questions and made it clear as day. Thank you so much. I appreciate the help. Where can I grab one of those?

 

We also have plenty of the reluctors. let me know how those development endeavors go.

BTW a freeze plug is a much cheaper option for plugging the speedo hole for all the others reading.

 

Be hard to thread a freeze plug Dalton!!

hint Hint wink wink you should combine those two things then I can just buy them 5 at a time from ya.

 

I don’t get how plugging the speedo hole resolves me reading my stock speedometer? This is what I’m talking about people coming in here throwing their ideas out and it’s back to square one. So are there options that work for speedo plug and play or do I need to tear down the tail shaft and heat and pound **** on and then when it breaks have the buy new ****. That’s what I’m trying to avoid. So the only option I see if what the op posted before with the wiring and conversion or Dakota makes a part for me and also a wheel sensor which is last resort. Plugging it sounds stupid to me. Or please explain that one...

 

Sorry, they were not discussing a solution to allow you to use your transmission (the way it is now) with an electric speedometer.
Just do what I showed you in the photos.

They were talking about making a custom VSS for a THM400... since the OEM VSS is very scarce.

 

You can find an adapter from Summit Racing or Jegs.

 

The easiest method is what vortec posted.
Use the stock speedo with an adapter to turn that signal from mechanical into digital

I was stating a way that you could have electronic speedo with a direct read. Using a sensor that most ECU's work well with

 

I'll add it to the ever growing list of things we should develop.

 

I feel ya there buddy...too many ideas and not enough time