1990 zf6, speed sensor part # 25007308 obsolete since 2003. I found one, but mega bucks. 1991 and up for same transmission is part # 10456089. not so mega bucks. My thoughts are, the transmission case is the same on all zf6's so one should interchange phisicaly. The replacement harness is the same for models 86 - 96. (two wire). So that parts covered. "Driven Gear" part# 25513047 is the same as 1994 with 3.45's I have 3.33's (rearend). The drive gear is the only part# that differs but should not make any difference because it's internal (I think) but should work because the driven gear is the same. All info came to me from a chart on this forum, which I'm finding to be a real valuable source of information, thank you again. So I the question is, Can I use it? does it interchange? The only thing I'm not sure of is, the old one develops 4000 pulse per second, not sure about the newer one. Will ECM read this or CCM depending on wether your looking at a helms manual, or haynes. I've since gave the haynes manual away, hope he dosen't hate me. Is there a Santa Claus, any thoughts?
Thanks
Scott

 

There are 4 different VSSs (that's a lot of esses). Two different series (early and late) and two different offsets per series. The offset has to do with the driven gear being properly located on the drive gear. There is one of each series for 35 to 40 tooth driven gears and another for 41 to 45 tooth driven gears. The offset is similar to the principle of two and three series diff cases in a rear end.

That would never work for a speedometer. What you have described, is a clock. The early and the late series send a different number of pulses per revolution. The early sends two, I believe, and the late sends four.

 

sorry, ppm pulses per mile.
OK now were getting somewhere. Of the four different types of sensors, two of them cover 2.59 - 2.73 Gear Ratio, ( one pre 90 #25007224 and 91 and on #10456091) That leaves us with two, old and new style,or old #25007308 and new #10456089. These are for the 3.07 - 3.45 Gear Ratio. As mentioned above the driven gear is the same on a 94 that uses the same sensor as the 91 or # 10456089. Now the sticky part,the signal or pulse goes from vss to ecm. I find that the ecm on 1990 is the same as 1991 but call for the different vss respectively. A little hard to follow but, I'm thinking this might work.

I was using this chart I found here Thanks to James93lt1 in a reply to macvettes http://www.corvetteforum.net/c4/vet...rGearshtm.shtml
concerning 1993 Speedometer Gearing - Which Gear??? on 9-22-05

so whaddya think? Could this work?

 

I couldn't get that link to work. I use THIS from time to time, among others. Is that the chart you were referring to?

It appears I erred when I said there were 4 VSS's. There are at least 5 and probably a total of 6. It seems, as per that chart, when they changed the pulses per revolution, they also changed the fitments between the auto and manual transmissions. I have found few errors in that chart. If you install the parts called for, for your year car, transmission, tire size, and axle ratio, you will be happy with the speedo operation.

I don't know how the VSS is wired. I cannot comment in whether your ECM is the same as anything else, But I'll guarantee you if you sub VSS's with no other changes, your speedo won't work properly. GM didn't change the part number to test YOU to see if you could sub it for another. There are other factors that allow for different gears in the 1994. Stick to what YOUR car takes and all will be well.

RACE ON!!!