I have an 85 T/A w/ 700r4 and I am going to be putting a speedo from a 87 T/A in it. I will be converting from cable to elecric driven speedo. I have talked to some parts stores and have been told that there were 3 different vehicle speed sensors listed for the 87 T/A. I figure one is for the manual and dont know about the other 2. I need to know a part number or something. I have tried searching but havnt found anything that will help. I would really appreciate it if someone could help me out here. Oh, and one thing I thought of is that it might depend on the rear end ratio. If that is the case I have 3.45s.

Thanks

Ben

 

25007308 is the number you need.

 

Thanks, and just out of curiosity what is the difference?

Ben

 

The diameter & # of teeth on the driven gear.

 

I have installed a 700r4 from a 87 GTA (with a digital dash) into my 82 Z-28. I'm converting from digital to mechanical speedo.
I may have the parts you need, if your interested in used parts.
You may have the parts I need.

 

Well, can you find out the part number of the one in yours. He said that the gears would be different for different ratios, so do you know what ratio was in the gta so we can figure out if thats the one I need. Even if it is a different one, I can get the other gears to make it work right? This is what people usualy change to change the speedo. What gears do you have, because the gears that will be on my mechanical setup is for 3.08s. Let me know because I would be interested.

Ben

 

Oh, and if someone that knows sees this before he replies could you let me know what gear ratios will have the right driven gear on the sensor for 3.45s. Oh, and another question is did the digital dashes use the same sensors as the electronic controlled analog ones because that is what I have.

Thanks again

Ben

 

I'm pretty sure the GTA had 3.27 gears, but not positive.
The RPO#s are missing.
It had a 9-bolt disc brake rear end.
I haven't pulled the electronic sender out yet, not sure if the part # is on it or not.

I'm thinking if you have electronic speedo, there will be a trigger wheel inside the tail shaft housing instead of a gear.
I'm pretty sure different size trigger wheels would be avaliable.

With the mechanical set-up, I'm thinking if the ratios are close, I can just get a different driven gear and use your drive gear,and driven gear housing.

A buddy was telling me a drive gear will fit abt 3 different driven gears. If the jump is too big, a different drive gear will be needed.

At the monent, I'm trying to get the brakes working. I'll try and pull the electronic sender later 2nite or tomorrow.

 

My tranny is on the floor so let me know because it wont take me long to get the stuff out for you. It sounds like I will be able to make what you have work(at most get a different driven gear). If I am wrong someone let me know.

 

Bad news.
The top part of the elec speedo sender seperated from the main part during extraction. I'm afraid it's a goner.
I can tell ya when I finally got it out, I found that there are gears inside.
Inside the sender is a small elec generator.
The driven gear rides on the generator shaft.
2 elec pins send the power out to the wires. (The 2 pins sheared off the generator during removal).
The only good news is that you may not have to remove the tail shaft housing from the tranny to install a drive gear since there's already one in there.
Hopefully it's the right size.

I got some part #s from the dealership. Going to see if I can find what I need locally. If I can't, I may still want your mechanical speedo drive parts.

 

I knew it would have gears, however the part numbers are different for the gears for the electric speedo as opposed to the cable speedo. That does really suck though. I guess let me know what the deal is here. If anyone else happens to have one laying around let me know.