I am looking at buying a 120 mph speedo off of ebay for my 84 Trans Am that has a 85 mph speedo. I've heard mention that after 85 they changed something from a speedo cable from the tranny to something electronic. Can anyone tell me what I would need to do to make this newer guage cluster work in mine. Thanks.

Sincerely,

Rob (brat1475)

 

http://www.hioutput.com/tech/speedo.html
There is also a link to this page in the tech articles section.

 

What kinda speedo are you buying? Model # and stuff? You may run into some other problems that the web page may not have covered, such as the speedo senders being a different size. If they are the same size, then great saves you some work. If they are not the same size, you have to go to the junk yard and buy a tail shaft housing from another 700R4 that has the correct size hole for your speedo sender. I went through hell getting my 120 electric speedo to work. I put an engine and trans from an 89 Camaro into an 89 Firebird. Camaro= mechanical Bird= electric. My problem was that the speedo sensor and gear (goes on the trans's tailshaft) was hard to find. All that I've tried from junk yards made the speedo shoot from 0 to 120 when the car is actualy going 0-1mph. This caused the engine to die.. Finally I go to the dealership and ask them what kind went in my car originally, and DAMN! It was one that was only placed in an 89 bird in the last four months of its production. They had four of these left in the whole state of texas. After ordering that one from Oklahoma and swapping it into the bird, it worked just fine. So my best advice to you is to find someone at a dealer ship who knows something about these things, tell them what your trying to do and have them give you the part number to the speedo sensor and gear that you need for your setup.

GOOD LUCK!

 

Hey, thanks for the info. The website has a lot of good info. As for the part number, the ebay page doesn't say. It shows the pic and says it's out of a 87 firebird. It's item# 7926157576 on ebay. Thanks again for the info.

Sincerely,

Rob