First, the drive gears: 15 tooth is gray, current GM part number is 8642620. there is no 16 tooth. 17 tooth is red, 8640517. 18 tooth is blue, 8640518. 19 tooth is yellow, part number not available to me at this time. Now, driven gears. First, these now come with a new plastic carrier, so you don't need to hunt up an old aluminum one. Second, there are 2 styles. Most pre-89 cars with cable speedometers use the 7-digit part numbers, while a few pre-89s through '92 will use the style with the 8 digit part number. Beware that both 34 tooth and 42 tooth are both green. so: 34 tooth green, 9774413/25513041. 35 tooth orange, 9780387/25513042. 36 tooth white, 1359270/25513043. 37 tooth red, 1359271/25513044. 38 tooth blue, 1359272/25513045. 39 tooth brown, 1359273/25513046. 40 tooth black, 1362048/25513047. 41 tooth yellow, 1362195/25513048. 42 tooth green, 1362049/25513049. 43 tooth purple, 1362196/25513050. 44 tooth dark gray, 9780470/25513051. 45 tooth light blue, 9775187/25513052.

What are the combinations for different gear ratios with stock tires (which many members will want)?

JamesC

I agree with JamesC. It would be nice to know the right combo of speedo gears, with what gears, and tire sizes that are common on our cars. Mine has been changed from 2.73 to 3.42. Still have stock sized tires, 235-55-16. Anybody have a chart of some kind, so lazy guys like me dont have to do the math!?? Ha! Ha!

You guys don't understand several things I expected everyone to. One, you're not supposed to post in a sticky before the moderator can make it a sticky and close it. I've already discussed with the moderator making these 2 posts into stickies. Secondly, to make an all-comprehensive table or graph, with every accurate combination and every popular, nearly-accurate combination, would take 74 pages. The math is simple, I can do any combo in less than 30 seconds, therefore, there's no excuse for anyone else failing to do so. That's why I just made 2 new Sticky posts. If you find you cannot figure it out for yourself, PM me.

Sorry to post in your soon-to-be sticky, but I made a spreadsheet a while back that has these part numbers along with a calculator to find out which ones you need.

I've attached it to this post.
Attila - If you're so inclined, you can spice this up with the missing part numbers, and maybe color it a bit nicer, and repost it in your thread if you want.

Nobody likes to do Math Also my spreadsheet has a nice RPM vs speed chart based on tire size and gearing. Very useful.

I filled in the blanks, but it's read only, I can't save it, nor a copy, nor upload the filled-blank version

Well you'll have to save it to your desktop, and all that funky jazz...

it, now I just have to re-fill all the blanks, then save, then up-load. Thanks for getting this ball rolling.

After several stickies of my own, I'm surprised to hear this. Live and learn. BTW, none of mine have ever been closed.

At any rate, the info you provide will be extremely useful to members--a sticky was long overdue, so thank you for your contribution. The following company furnishes drive and/or driven gears for the 700R4 as well as other pertinent info:

http://www.transmissioncenter.net/sp...n_______va.htm

Here's a brief how-to swap the gears:

http://sethirdgen.org/vss.htm

JamesC

Oh. okay, my apologies.

I'm posting the next 4 images for Sonix to use to update that excellent auto-calculator, if Sonix is willing.

oops, well,..

and hopefully this..

holy crap guy, you're taking it to 4 decimal places?!? Sheesh! I'm at work now, if somebody else wants to add those additional cells feel free. Preferably someone who understands excel math functions and won't butcher anything.

Basically I just have the choices listed, and you fill in what you have. If we want, we could use drop down boxes to choose. If nobody jumps in and does the work for me, I might be able to tweak this tonight, or tomorrow.

alright whats the formula to do it on a calculator? running a 3.23 gear and 70 series tires. just let me know the formula so i can figure it out myslef and never have to ask ever again.

That's what my other sticky is for.

didnt see it yet. ill go check it out. i just clicked "new posts" i didnt actually go into the "transmission and drivetrain" section. my bad.

Here is some info Regarding ratios and tire sizes and speedo gears

http://www.shiftritetransmissions.com/speedo.htm

The top part of that is the same info I already gave, and the lower part is far too vague.

Can anyone Tell me If a Transmission out of a 1991 Camaro Rally Sport will work in My 1984 Z28 HO?? They are Both Coded M5, A4 however I was told there is an issue with electronics. Any advise would help before I go Changing this out?
jsalazar@brenneraero.com

i have a question i just took out my stock 700r4 tranny and put in a tci street fighter and the street fighter has and electric speedometer so i just switched out the gear and put my stock gear

i accidently clicked post..i put my stock gear in the tci tranny so i could hook up the speedometer cable will it affect it in any way? thank u

I can't imagine why.

JamesC

Ok im sorry i dont ungerstand any of this can someone plz tell me what gear do i need i have a 700r4, 3.23s gears, 275/60/15 tires

stock was 2.72s or 2.42s

Start with my other sticky. Or if you want me to do it for you, after I was so kind as to post so much accurate info for free, then pay me.

Okay, I've had enough whining from the lazy and the weak-minded.
So I decided to just start on a cheat sheet. Not all combinations
can be exactly calibrated, but here's the best possible calibration
for each combination given.
This first batch is for anyone using a 700R-4 with any of these tire
sizes on the rear axle of their car:
205/60R15
225/55R16
245/50R16
245/45R17
275/40R17
315/35R17
245/40R18
If your tire size isn't here, don't use these results.
2.73:1 use 41 tooth driven with 19 tooth drive
2.77:1 39 18
2.86:1 38 17
2.93:1 39 17
3.00:1 40 17
3.07:1 41 17
3.07:1 36 15
3.08:1 41 17
3.08:1 36 15
3.23:1 38 15
3.23:1 43 17
3.25:1 38 15
3.27:1 44 17
3.31:1 44 17
3.31:1 39 15
3.42:1 40 15
3.45:1 41 15
3.50:1 41 15
3.54:1 42 15
3.55:1 42 15
3.70:1 44 15
3.73:1 44 15
more no cal.

Cheat sheet 2. Again, it's for 700R-4 cars. But with a new list of tire sizes,
and a new set of calibrations. If your rear tires are any of these sizes;
255/60R15
255/55R16
255/50R17
255/45R18
285/40R18
255/40R19
255/35R20
NO other sizes for these calibrations:
2.73:1 no cal
2.77:1 35 17
2.86:1 36 17
2.93:1 37 17
3.00:1 38 17
3.07:1 39 17
3.08:1 39 17
3.23:1 41 17
3.27:1 44 18
3.31:1 37 15
3.42:1 38 15
3.45:1 no cal
3.50:1 39 15
3.55:1 45 17
more no cal.

bump

You don't need to bump a sticky, ever. Especially when you haven't left any un-answered questions hanging, waiting for an answer.
I'm still available, so you can PM me if you need help with choosing 700R-4 speedometer gears.

Are there any combinations of speedo gears that wont mesh? Reason I ask is I have a 17t red drive gear, and a 38 tooth blue driven. I need to slow the speedo down, so I was gonna change to a 40 something driven. Just want to make sure that the teeth will mesh correctly. I put 3.73 gears in it, and it hits the speed limiter at the track. I am not worried about getting it exact, just want it to not hit the limiter, And dont want to tear it down to change the internal gear. Its hitting the limiter right at the finish line, so a 5mph difference is all I really need. Thanks

question... is there an easy way to bypass this transmission sending unit for the speedometer for my 86 T/A with the TPI option? i pulled out my computer and harness when i replaced my engine with a 350 4bbl



please help i am interested

thanks for the calc

Question, for any and all. I recently put a cabed 350 4 bolt into a 92 z28 25th. and added a 700r4 from same year rs 305 TBI. Granted the RS had 203,XXX miles ran, but quikly became our parts car.

When I was putting trans in, i replaced the front seal and everything els seamed good. Upon test driving though, the car shifted a little high and i dont thing Over drive kicked in, but it goes in all 4 gears. Also the tach read 3,800 rpms at 70 mph. Trans is sluggish do to age and how many miles its seen, but should that stop it from hitting over drive?

Also note that the two plugs for the tranny in the 92 Z28 were little broken so we borrowed some from a z28 parts car we also have. Every gears works, shifts normal for the 700r4 but even at 40mph its wont kick down..yes TV cable is hooked up but may need adjusting...need help..or maybe new trans?

Great info thanks!

How hard is it to do this actual swap? Where in the transmission?

Post #9, second link.

JamesC

5 spee swap uber easy...i got worked up worried about it..do it its worth it. Then when you have alot of power go to a TKO 5 speed : )