Atilla the Fun

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.

JamesC

iTrader: (5)

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

JamesC

fullcircle

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!

Atilla the Fun

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.

Sonix

iTrader: (1)

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.

Atilla the Fun

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

Sonix

iTrader: (1)

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

Atilla the Fun

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

JamesC

iTrader: (5)

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

Atilla the Fun

Oh. okay, my apologies.

Atilla the Fun

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

Atilla the Fun

oops, well,..

Atilla the Fun

and hopefully this..

Sonix

iTrader: (1)

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.

Ca[maro]88

iTrader: (2)

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.

Atilla the Fun

That's what my other sticky is for.

Ca[maro]88

iTrader: (2)

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.

Brett427

iTrader: (2)

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

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

Atilla the Fun

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

joe_salazar668

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

DVR408 88 iroc

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

DVR408 88 iroc

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

JamesC

iTrader: (5)

I can't imagine why.

JamesC

chrisblazzer89

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

Atilla the Fun

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.

Atilla the Fun

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.

Atilla the Fun

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.

MSRed91Camaro

iTrader: (2)

bump

Atilla the Fun

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.

tylera189

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

xcoltonx

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

HUSSAIN

thanks for the calc

rmulle1986

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?

chevman24

iTrader: (1)

Great info thanks!

blue birdy 87

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

JamesC

iTrader: (5)

Post #9, second link.

JamesC

rmulle1986

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 : )

dabird07

iTrader: (10)

this helps alot!!

two-if-by-sea

iTrader: (22)

I started with a 37 tooth red, and I purchased a spare red, and a 44-tooth grey using the above part numbers.
this is what I started with:


Here is the new red gear:


1) Why does the shaft stick out so far on the new one? Do I need to purchase a different shaft, some sort of adapter, or what? Both the grey gear and the new red gear have this issue.

2) The grey 44 tooth gear is slightly larger in circumference than the red gear. Once I figure out what the deal is with the shaft, will this gear be a direct swap, even though it is physically larger?

chevman24

iTrader: (1)

You need an adapter piece for 40-44 driven speedometer gears. I dont have the slightest clue as to where someone would purchase it. But I know i needed one when I switched to a 15-44 combo. But I have the all plastic gears without the rod. So what i just stated may be a waste of time.

budget builder

iTrader: (3)

thx atilla!

Wife'sCar

iTrader: (1)

Just bought my wife a 91 RS 5.0 that's had it's axel swapped to 3.42. I have used a calculator and understand that I can get a new drive and driven gear and have it accurate.

My question is this;
it had 2.73's which from what I have read above would make my trans a 19 yellow drive gear?
Being as I don't really care to pull the trans apart and am not worried about it being exactly correct, is there a certain driven gear I can use to get the speedo in the ball park? Right now it's about 20 miles off at 60. I'd be perfectly happy with around 5 or so.
My buddy I bought it from told me it was possible to get a driven gear to work with the drive gear already there to get it closer to correct but wasn't sure which driven to get or how to figure out which one.

Is this even possible?

Prodigious

Okay guys, I apologize for my ignorance to this, but I read the the thread, and I'm afraid I really don't follow on how to calculate the speedometer gears I need to correct my speedometer. I recently installed 4.10 gears in my car, I have a 1992 Z28 with a 700r4 and 245/50/r16 tires. Can someone help me out with this? Its quite frustrating to have my speedometer reading 100 mph when I'm only going 65 mph.

Never mind, I calculated that the closest I could get is with a 15 tooth drive gear and a 45 tooth driven gear. If this is wrong please let me know.

cosmick

The 9775187 45-tooth light blue for mechanical cable is discontinued, and PATC doesn't have them, but I found 2 on E-Bay, so I ordered the cheaper one, $13 shipped. The other one was $15.

JuanZ28

1987 5.7 TPI 700R4 speedometer transmission gear. What do I have here and where can I get a replacement. Thanks in advance.

Faolan

Would 19 drive and 34 driven work with a 26" tire and 3.42 rear? Bowtieoverdrives calc says it will but no others do...

Or would my stock drive gear (17) work with a 45.


According to that it wouldn't work on my tbi with ebl?

Faolan

count the teeth and search on eBay. The red one looks fine from that angle.
ex. "700r4 40 tooth speedometer gear"

Chevy86 IROC-Z

iTrader: (17)

Same issue here. Lol