junior419

Hi I need help. Have been doing alot of research on this subject to fix my speedo problem.

I have a 1992 rs 305 tbi
235/55/16
4.10 rear end

Vss I removed the speed sensor to check what color drive and driven gears my camaro currently has. Both were red.

The problem I have ran into. Is the information I have found basically says Red is ethier 9 or 17 tooth on the drive gear and 37 on the driven.

the calculator I used basically says I need a 15 tooth drive gear and a 45 tooth driven gear. but from what I read here I have my info messed up.

Cam anyone give me some info on what drive and driven gear I need?
My vehicle tops out at 70mph because it thinks I'm going 110mph. also it shifts at wrong intervals

Pat Hall

iTrader: (31)

The red drive gear you have on the output shaft of your 700r4 is the 17 tooth gear. The red 9 tooth drive gear is the one that comes on the T5 manual transmissions. I went to my trusty online speedo gear calculator and here's the info I found. The problem is that even with a 15 tooth speedo drive gear, you'll need a tire that's 28 inches tall to be able to get the correct driven gear. Reason being is the driven gear commonly available with the most teeth is the 45 tooth. There's also a tire calculator on the website I use, and the right size tire that's 28 inches is 235/65/16. That tire is exactly 28 inches tall. So if you pick up 2 235/65/16 tires and put them on the rear of your car, you'll be able to use the 15/44 tooth gear combo and have your speedo almost perfectly accurate. The exact tooth count of driven gear the calculator listed with the 15/44 gear combination and 235/65/16 tires is 44.3. So using those tires with the 15/44 gear combo should get you right around plus or minus 5 mph accuracy on your speedometer. Btw, I also tried the calculation with a 235/60/16 tire size, and the calculator said 45.7 on the driven gear. So yeah, going with a pair of 235/65/16 tires and the 15/44 speedo gears will get your speedo the most accurate. Btw, the most reasonable place I've found for buying speedo gears online is LA Speedometer and Gear. They have an Ebay store, or you can go through them directly online to purchase. PATC Raptor Corp. also sells 700r4 speedo gears, but they're a bit more expensive and don't have as many gears available as LA Speedo.However, come to think of it, you're going to need the electronic style 44 tooth drive gear, and PATC Corp may be the place that has that. Btw, the 44 tooth gear is gray in color. If you strike out on finding it at the 2 sites I listed, you might want to see if you can find a used one on Ebay. Hope this helps.

junior419

Thanks alot pat hall. I didn't know t5 transmissions were the manual transmissions. I have a 700r4 automactic and I also used LA speedo*s website and their calculator. I just couldn't figure out what I needed to buy since their site was a little confusing in my opinion. Also the electronic speed sensor and the cable driven speed sensor seem to use different style driven gears. Not 100% on that but I didn't want to guess so I called them. So for anyone with a 4.10 gear ratio. You will need to buy part numbers #54x the 15 tooth drive gear. #55 the 44 tooth driven gear. #55xx the white 40 to 45 driven gear speed sensor. The cost was around $103 out the door and a 3 day wait via priority mail. Then like pat said, 235/65/16 is the tires size you will want with this set up. Thanks again pat and I hope this helps someone else who is looking for this info.

formula00ra

iTrader: (1)

For cars with a VSS, you won't need to go through all the trouble of looking for gears anymore to make your speedo work correctly. You can get an electronic ratio adapter and install it and make the speedo and odo work perfectly. Installs very easy and is an excellent product.

85Z28NOS

iTrader: (2)

I have a 20T gear from my T5 for sale

Steve Quinn

iTrader: (2)

So my VSS has been leaking on my T5 90 IROC since i bought it 2 years ago. Been looking for solutions, the lack of available replacement VSS and gears. I’m at the point i have to do something, reerend is apart and 3.70’s are going in.

So here is my idea on a solution, if i understand this right. 82-89 car with t5 use the same gears and adapters as t10 and th350 transmissions.

i will use

TCI GM Speedometer Gears 880002
https://www.summitracing.com/parts/tci-880002/overview/

TCI Speedometer Gear Housings 880021
https://www.summitracing.com/parts/tci-880021/overview/

JTR Speed Sensor #4PAC, it’s a 4000 ppm sensor, 2 wire
This will convert the mechanical into electric, as it screws on to the adapter housesing.

https://jagsthatrun.com/products/speed-sensor-4pac

Am on on to something that could be a VSS replacement?

formula00ra

iTrader: (1)

https://jagsthatrun.com/products/speed-sensor-4pac

I have this speed sensor brand new and I will sell It to you for 80.00 shipped if you are interested.

Steve Quinn

iTrader: (2)

Ok I have the drive install in the trans, so far it seem to fit. Formula00ra do you have any pictures of your unit? Why did you end up not using it?

Thanks

jmd

iTrader: (4)

There are early (slightly smaller drive gear, larger driven gear) Chevy TH350 speedo gears. Sometime before the T5 third gens, they changed to the larger drive gear, smaller drive PN gear sets that were used in T5 third gens.

Both use the same driven gear sleeve and, as a matched set, an early set can replace a late set, and vice versa.

You're on the right track with your solution for VSS availability.

formula00ra

iTrader: (1)

I can get pictures for you. Just PM me and I'll send them along. As you may know, Camaro's used a cable, Firebirds used a VSS. The transmission I used came out of a Camaro so it was set up for cable but I was able to find the correct VSS used on the Firebirds so I decided to use that and employ the speedo adjustable electronic box at the gauges.

kenbob

Hello gentlemen I'm in need of a 21 tooth driven gear for a shaft mounted t5 electronic speedometer sending unit. If anyone needs a trans am t5 vss look on eBay part number 25007350 please let me know if you are willing to sell the part I need I also have a mechanical speedometer sending unit with metal shaft and 22 tooth gear

kenbob

Hello i'm looking for an electronic 21 tooth driven gear. Im doing a T5 swap and I have an electronic speedometer I am also installing 3.70 years into my 9-bolt so I believe that the right combo is 7 tooth drive and 21 tooth driven so I need the metal shaft mounted 21 tooth please help me I've been collecting parts for 17 years and I'm almost done i was in the army and overseas is why I've taken so long

raptor427

Could use some help here on this too. I think I've overthought this. I have a T5 manual tranny (factory) with a PM style VSS with a GREEN 23 tooth gear wheel on it. Now while the car DID have 16" rims with 245/50R16's I've dropped to 15" rims with 235/70r15. The speedo shows approximately 3-4mph over what I'm actually doing (well according to GPS speedo). I have NO idea what's in the rear end - had it replaced at one point several years ago. Is there anything stamped on the outside to be able to tell what's inside? I CAN live with the speedo readout if necessary, but it'd be nice to have it read a bit more accurate. Thanks in advance.

Will

kenbob

The ring gear should have the gear ratio stamped on it whether it's a 9 or 10 bolt without that information I can't help you I have an extra 19 tooth and red drive gear I believe it's a 9 tooth I believe if your car is a factory 5 speed car it either cam with 3.27/23 depending on 9 or 10 bolt or 3.45/42 again 9/10 bolt while some tbi cars came with the 3.08 gear ratio but I believe that's 88-92