speedometer - Third Generation F-Body Message Boards

warrenb2 · 11-07-2009, 12:46 PM

HELP, I have a 1990 firebird formula I have replaced the cluster and speed sensor on 700r tranny but my speedometer dose 140 mph in first and second gear and returns to zero when crusing Im not sure if I put in the wrong cluster or wrong speed sensor I have the 5.7 motor any help would be appreciated

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z28 TPI · 11-07-2009, 01:03 PM

Did you change the speedo when you changed the cluster? If you did, did you get the speed sensor for the changed speedo or the original one? I would start there

warrenb2 · 11-07-2009, 06:14 PM

Quote:

Originally Posted by z28 TPI

Did you change the speedo when you changed the cluster? If you did, did you get the speed sensor for the changed speedo or the original one? I would start there

no I didnt replace the speed sensor when I replaced the cluster I thought that all speed (magnitic) were the same am I wrong and were would I find a new one or do I have to match the numbers of the cluster?and speed sensor? Thanks

top1ess · 11-08-2009, 01:25 PM

hey i just changed my cluster for a 1991 z28 305 5spd with the 180 km to the 240km top out speed from a 350 any idea why i cannot get my shift light to come on? every light is lighting up except that light.... thanks

z28 TPI · 11-08-2009, 02:16 PM

Hmmm I would start by changing the sensor there might be a relationship between the sensor and the speedometer. On mine its cable driven so if i change the speedo I have to change the gearing in the tranny to match. I would say that it would be the same thing with your application change the speedo change the sensor.

z28 TPI · 11-08-2009, 02:17 PM

I know it sounds dumb, but have you looked at the shift light to make sure its not burned out?

top1ess · 11-08-2009, 03:06 PM

Hey thanks for getting back to me I did think about the light bulb being the reason but do I need to also change that speed sensor from my 305 to the 350? Or is it a gear that I need to replace? If I put all the gauges into my original case cluster housing do u think I may solve my problem?

warrenb2 · 11-08-2009, 04:20 PM

heres the kicker my700r4 tranny has a magnitic pick up and everplace i try to get a replacement wants to send me a geared one is this tranny a freak or do I need to install a gear in tranny?

z28 TPI · 11-08-2009, 05:33 PM

The 700r4 tranny has in the tail shaft a case looks like dark brown resin, this is the piece that the cable for the speedometer is to connect to. I know that the 4l60e trannys are electric 700r4 trannys. Do you know if your transmission is a 700r4 or a 4l60e? They both will work no problem, but in your case it might be a 4l60e. Try looking for the sensor for that transmission. That might be the reason why everyone is trying to give you a gear as opposed to a magnetic sensor. PM me if you have any more questions.

warrenb2 · 11-08-2009, 06:02 PM

Thank you for your help i know that its a 700r4 it must be the cluster that i got because im geting a voltage reading all the way through the ecm. The guy who I bought the cluster from said that the cluster i bought from him was good but i notice that the speedo is 140 but his tach is only 6k were my old one was 8k.Im still researching this. Im still from the old school of cabled transmissions and all this computer generated stuff is is different to me but Im learning.

camaronewbie · 11-08-2009, 06:19 PM

Can't be a 4l60e - those are 4th gen specific and have a whole different computer system to control the tranny itself (their own PCM), where as the 3rd gen cars don't have the computer system to manage a 4l60e (unless someone spent an absolute boatload of cash to install a new computer system for a 4l60e - last I saw it was about $1300 just for a computer).

z28 TPI · 11-09-2009, 03:36 AM

Thank you I knew I might be wrong good to know lol. Well now that we know its not the tranny gotts look at the cluster. Warrenb2 I will try and help you by looking at the diagrams.