Trans speedo help

[Stuart]

Okay before i even start i will apologize in advanced. I know the question I am about to ask is on this forum somewhere but i just find it easier to create a thread instead of searching for hours.
So now onto my problem. I have swapped over a chevy 350 in my 84 cutlass and now have a 700r4 that i just rebuilt to go in. The one problem i have faced is this is an 87 and does not have the mechanical speedo input. I have found a couple different units that convert the signal to mechanical but are pretty pricey at $300. Also these boxes seem a little complex to calibrate right. Anyhow it would be much appreciated if i could get some help trying to figure an alternative or if anyone can point me in the right direction so i can use a mechanical driven speedo. Thank you to all

 

[455'ed80Regal]

I am guessing that your transmission has no provision for a speedo cable? If that is the case then all you would need to do is remove the driven speedo gear and sender from the tail shaft on the transmission and acquire one for use with a cable. Without knowing your tire size or gear ratio i can't tell you what speedo gears you will need to make your speedometer accurate again. Hope that helps

 

[Stuart]

I am guessing that your transmission has no provision for a speedo cable? If that is the case then all you would need to do is remove the driven speedo gear and sender from the tail shaft on the transmission and acquire one for use with a cable. Without knowing your tire size or gear ratio i can't tell you what speedo gears you will need to make your speedometer accurate again. Hope that helps

Well I believe the speedo is based on a magnet inside the tail housing. I will have to double check with how it all is set up and i can take some pics for you. I currently have 14 inch wheels and tires but i do plan to go to 16. if it is that simple to replace with a mechanical speedo gear that would be great.

 

[UNGN]

swap in an earlier "non E" tailshaft on the transmission.

I played with electric RC planes for 10 years and I'm confident someone could easily make a box with a brushless motor that clipped on to the back of the speedo that was controlled by a box plugged into the Trans for about $75, based on the cost for these individual parts for electric RC aircraft, which are unbelievably cheap. If I was an electrical engineer instead of an Aerospace engineer, I'm also pretty sure I would be making/selling these boxes for $150 today. $300 appears to be currently be the number, however.

What about a GPS speedo? I have one of these in my 2+2 and it is way more accurate than ANY mechanical speedo: (+/-.2 mph @ 168 mph - it has a small digital readout below the sweep reads out to the .1 mph).

 

[Stuart]

swap in an earlier "non E" tailshaft on the transmission.

I played with electric RC planes for 10 years and I'm confident someone could easily make a box with a brushless motor that clipped on to the back of the speedo that was controlled by a box plugged into the Trans for about $75, based on the cost for these individual parts for electric RC aircraft, which are unbelievably cheap. If I was an electrical engineer instead of an Aerospace engineer, I'm also pretty sure I would be making/selling these boxes for $150 today. $300 appears to be currently be the number, however.

What about a GPS speedo? I have one of these in my 2+2 and it is way more accurate than ANY mechanical speedo: (+/-.2 mph @ 168 mph - it has a small digital readout below the sweep reads out to the .1 mph).

After some research i have found a kit to swap out the electronic one with the mechanical one on ebay for $83 so i might be looking into that. Its much easier than finding a tail housing and still having to swap out gears.

 

[565bbchevy]

Well if the tail housing set up doesn't work I do like the idea of the GPS speedo since it will always be accurate when switching tires sizes or even gear ratios but would require some fabrication to fit the dash but if you plan on any sort of custom gauge panel in the future than this would be the thing to get.

 

[Stuart]

Well if the tail housing set up doesn't work I do like the idea of the GPS speedo since it will always be accurate when switching tires sizes or even gear ratios but would require some fabrication to fit the dash but if you plan on any sort of custom gauge panel in the future than this would be the thing to get.

Could either of you explain or even send a link of a gps speedo please. I would like to so some research and look into that for sure to kind of get away from the mechanical but i do like my gauge cluster

 

[565bbchevy]

They are by no means cheap but they are nice, Autometer and others also make them but the first ones I looked at were Speedhut.
http://www.speedhut.com/gauge/GR338-GPS-01/1/GPS-Speedometer-120mph

 

[Stuart]

They are by no means cheap but they are nice, Autometer and others also make them but the first ones I looked at were Speedhut.
http://www.speedhut.com/gauge/GR338-GPS-01/1/GPS-Speedometer-120mph

so if im correct, you dont

They are by no means cheap but they are nice, Autometer and others also make them but the first ones I looked at were Speedhut.
http://www.speedhut.com/gauge/GR338-GPS-01/1/GPS-Speedometer-120mph

i really like this unit. Thanks for the link. It's way easier to hook up and way better. I might be looking into this

 

[565bbchevy]

I really like this unit. Thanks for the link. It's way easier to hook up and way better. I might be looking into this

I like the Speedhut gauges because you can customize them to match your existing gauges or to just make a different style that you like.