Hi,

The speedo on my 91Z intermittently drops to 0mph. Any ideas as to what is going on, and where to look?

Thanks.

 

your speedo is electronic, if you didn't already know, so the first thing i would do is to check the wiring to the VSS sensor on the tranny, just make sure it is well connected, no visible breaks in the wiring, etc. beyond that, i'm not much help, don't know a lot about that system... i'm sure someone else here can help you more...

KAM

 

Thanks KAM,

Just where is the VSS, and is it something easy to spot crawling around under the car?

 

I don't know if this would be similar with an electronic speedo, but in my old car ('82 Bonneville) the mechanical speedo started bouncing, then eventually quit. turns out the driven gear in the tranny for the speedo broke....if it repeatedly drops to 0 and then bounces back up immediately only to drop again, it might be something similar....

 

it's on the driver side of the tranny, if i recall. can you tell i don't remember much? sorry, just trying to help some... it was a long time ago i put my tranny back in and haven't paid much attention to it since... other than when i unloaded all the fluid on the street right after i moved in to my new house, but... we won't go there right now... at least it missed my driveway

i think there's only two cables on it anyways - one for vss and the other for the torque converter lock-up... you'll see 'em...

KAM

 

yep. driver's side of the tranny, right by the tailcone (just in front of the back end of the tranny by the driveshaft). at least, that's where it is in TH350s...

 

Thanks everyone. I'll give it a check this weekend. It's possible I disconnected something as I was doing a tune up this past weekend and may have bumped some stuff (though I doubt it is related).

Chymos,

That does sound exactly like my problem. I think the 700R4 has a drive gear also, which may connect to the VSS? Just a guess. The bugger needs a rebuild anyway. T-56 or 700R4 rebuild, decisions, decisions.

91Z28-350

 

personally, I'd do the T-56 swap