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Yes. It is a factory electric speedometer with automatic transmission. The vehicle was originally a RS 25th Anniversary Edition, but the rear-end had to be replaced and it
was replaced with a Z-28 rear end. My speedometer is indicating about 10-15mph faster than I am actually going. Please let me know your thoughts and the next steps.
I've also got a red DRIVEN gear for the electric sending unit...... If you can't work out a deal with Brian; LMK.
FYI:
The Red 37 tooth gear was used for Z28's with 2.73 gearing and 15" wheels. If your car has 2.73 gearing and 16" wheels you'll want a 38 tooth Blue DRIVEN gear. ( I do NOT have a 38 Tooth Blue ! )
Yes. It is a factory electric speedometer with automatic transmission. The vehicle was originally a RS 25th Anniversary Edition, but the rear-end had to be replaced and it
was replaced with a Z-28 rear end. My speedometer is indicating about 10-15mph faster than I am actually going. Please let me know your thoughts and the next steps.
Thank you John.
helo101
Good Morning John:
Sorry for the late response. I am interested in purchasing this part from you. Please let me know how to proceed.
Sorry for the late response. I am interested in purchasing this part from you. Please let me know how to proceed.
Thank you very much!
Helo101
Just send me a Private Message ( PM ) that includes an offer for the gear and your ZIP code so that I can get a shipping quote. I'll send you a reply ASAP with all the remaining details.
** FYI A 37 tooth Speedo gear MUST be mounted on the correct VSS. The correct VSS will be BLACK. The BLACK Thirdgen 90-92 VSS is made specifically for 37-39 tooth DRIVEN gears and the WHITE 90-92 VSS is made specifically for 40-45 tooth DRIVEN gears. If your current VSS is WHITE,......... you will need to purchase a BLACK VSS to use with a 37 tooth DRIVEN gear !!! The RED 37 tooth gear is shown in this pic; as well as both types of 90-92 VSS's
Just send me a Private Message ( PM ) that includes an offer for the gear and your ZIP code so that I can get a shipping quote. I'll send you a reply ASAP with all the remaining details.
** FYI A 37 tooth Speedo gear MUST be mounted on the correct VSS. The correct VSS will be BLACK. The BLACK Thirdgen 90-92 VSS is made specifically for 37-39 tooth DRIVEN gears and the WHITE 90-92 VSS is made specifically for 40-45 tooth DRIVEN gears. If your current VSS is WHITE,......... you will need to purchase a BLACK VSS to use with a 37 tooth DRIVEN gear !!! The RED 37 tooth gear is shown in this pic; as well as both types of 90-92 VSS's
I'm worried you're going in the wrong direction here. If I'm wrong, please excuse my interruption. You say it now has a "Z-28 rear end" and that the speedometer is reading high. That sounds like the original 2.73 gear has been replaced by a 3.23 gear, which would result in the speedometer reading about 18% higher than actual speed. If this is the case, you would need the gray 44 tooth driven gear. This would also require swapping out the VSS to the white version shown above. You should have a red drive gear already. My 1990 Formula came with 2.73 gears and auto trans. I swapped out the 2.73 for 3.23 gears. My car came with the red drive gear, but I had to replace the black VSS with the white VSS and then go to the gray driven gear. If I had not swapped out the VSS, the drive gear would have been chewed up, as the mesh of the gears would have been incorrect. You really need to know (for sure) what your rear end gears are prior in order to properly address the speedometer situation.
You really need to know (for sure) what your rear end gears are prior in order to properly address the speedometer situation.
EXACTLY !!! This is why I placed so much detail / info in my messages. helo101at no time have you listed the rear gear ratio that you HAD, or HAVE NOW. I've done my best to explain things and have no problem selling you a RED electric speedo sending unit DRIVEN gear,...... but there is no way for me to know if this is the correct 'fix' for your exact problem and I would just be simply selling you what you asked for.
**The Red 37 tooth gear was used for Z28's with 2.73 gearing and 15" wheels. If your car has 2.73 gearing and 16" wheels you'll want a 38 tooth Blue DRIVEN gear. ( I do NOT have a 38 Tooth Blue ! ),.....The BLACK Thirdgen 90-92 VSS is made specifically for 37-39 tooth DRIVEN gears
You really need to know (for sure) what your rear end gears are prior in order to properly address the speedometer situation.
My apologies for the late response. I finally got the correct information on my rear-end which is 3.23. Thank you John and rt66er for your detailed information. It is my error that I did not read the information you provided in its entirety. Being in software, staring at three monitors all day and all the "fun" that goes along with it, my pupils sometimes dilate, I begin to drool and lose cognitive ability when I have to look at something technical at times.
So it looks like I will be needing the "grey" 44-tooth gear and "white" VSS module. Please contact me so we can finalize the next steps.
The VSS is going to be the hard part, as they are no longer available. What you need is GM part number 10456089. There's one in the "For Sale" section on this forum, but the ad is almost a year old, so though it's probably no longer available, you could check. https://www.thirdgen.org/forums/engi...nic-speed.html
There's also one for sale on EBay; just do a search with the part number.
For some unknown reason, even though the gray gear is supposed to be the correct gear, it didn't quite get there in my car. I had to move up to the 45-tooth to get my speedometer right. I think I still have a gray gear; I'll have to look and get back to you.
best solution would be to inspect and determine which pair of gears you have now in the trans for speedo/vss. then download a gps app that does trip measuring. go out and drive for 10 miles, per the app, then check the trip on your odometer. that will give you a % off you are given your tires and rear diff gears.
then do the ratio of the new speedo gear pairs and determine which combo gives you the closed to accurate trip (and mph). https://www.thirdgen.org/forums/tran...ml#post6420726
