i did a tranny swap (700r4) and of course the speedometer connections are different. the trans i just put in has a cable speedo sensor while the old one has a electronic. does anyone know if they make a converter to fix this? also will this do any harm besides keep me from having a speedo?

Can you swap the tail ends from your old tranny?

that i dont know.... i mean i believe its possible to do it but will it work?

im off work today so ill go out and try that now.

You need to remove the tailshaft housing (4 bolts) and remove mechanical gear from output shaft. I believe its held on with a clip. Next remove tail housing from your old trans. Use a gear puller to remove speedo gear off old shaft. Put it on replacement trans output shaft and put the old tailshaft housing ( the one that has the vss in it)
on your new trans. Plug in connector and speedo will work.

IIRC, you should be able to remove the cable-driven sleeve and gear from the replacement trans, and replace it with your original electronic VSS. I'd think you'd be good to go, unless you need to swap out drive and/or driven gears to make the speedo read correctly.

JamesC

Sorry guys mechanical speedo cars use a plastic gear on the output shaft while electronic speedo cars use one made of ferris metal. Plastic gear won't give speed signal to vss.

This is not true. The thirdgen 700R4 VSS is still gear driven. There are 3 drive gears 15 tooth(gray), 17 tooth(red) and 18 tooth (blue). These are the exact same for mechanical or electronic speedometers. The VSS housing makes the conversion from mechanical to an electric signal.

JamesC is correct, you can simply swap in the old VSS from your old transmission, as long as you have the correct drive gear. If they are not the same color, you'll need to either replace the drive gear from your old tranny which involves removing the tailshaft, or see if there is a driven gear with the correct tooth count that will work for your combo and purchase that.

Yes they are both gear driven. However mechanical speedo cars use a plastic gear held to the output shaft by a clip. Vss cars use a ferris metal gear that is pressed onto the shaft. Tell me. if you understand anything of how a vss works, how is the vss going to pick up a signal from a plastic gear that is used in mechanical speedo applications. My next question is, have you ever taken apart a 700r4 of each type to see the difference.

Additionally, please explain to me how the vss is going to pick up a signal from a plastic gear. If I had a way to upload a pic of the 2 different gear setups, you would notice the mechanical speedo gear is sprial cut to mesh with the other part of speedo gear. While the vss type gear is straight cut, and made of metal, so the vss can pickup magnetic pulses. You may be a senior member Jay, but if your answer is any indication of your knowledge, I would go back and hit the books some more.

I'm not particularly familiar with the electronic set-up, but doesn't the VSS for both the 700R4 and the T-5 have a plastic driven gear with a metal piece as a part of the gear itself, such as those in the following link:

http://www.transmissioncenter.net/sp...0gear%20driven

JamesC

You're going to have to eat crow after reading my post, because you're thinking of later model transmissions, such as 4L60E's and T56's. They do have magnetic pulse generators in them with a metal reluctor wheel on the tailshaft. But our thirdgen VSS's use plastic speedo gears on both the tailshaft and the VSS, no matter if they're cable driven or electronic. The plastic speedo drive gear on the tailshaft turns the plastic driven gear in the electronic VSS, which creates a pulse signal that the ECM translates into vehicle speed.

And as said above to the original poster, the cable VSS and the electronic VSS are interchangable. Simply remove the cable VSS and put in your electronic VSS in its place, assuming that the plastic speedo gear on the tailshaft is the same on both transmissions.

I just took the tailshaft housing off a 1989 700r4 and guess what I found. A steel rotor ring just like I said it would be. If you'd care to look at the link you put up and scroll down to #70 you will planely see 4L60E /700R4 on these parts, which means both transmissions use them. And as I said you better go back to the books and learn about the cars you are giving advice about. Maybe because I'm a newbe to this site
makes you think that I know nothing, but the fact is I've been into 100's of 700r4, 4l60, and 4l60e transmissions and know exactly whats in them.

Since a picture is worth a 1000 words, here is one from the automatic transmission service group also known as atsg. Pic is taken from the 700R4 manual coving 1987-1993. If these cars didn't use these, why do you suppose the info ended up
in the repair manual

I dunno what to tell you then, because every f-body 700R4 I've been into has a plastic speedo gear on the tailshaft.

The 4L60E's have the metal reluctor ring. Some 1993 trucks have 4L60E's, so that could be why your 87-93 book lists them.

*shrug*

Do you not just read my post where I took the tailshaft off a 89 700r4 which came new in an early 90 f-body, it was the original trans from my 1990 camaro rs. You are confusing the early electronic cars which used a speedo gear on the vss 86-89 are the years, I think, with the true vss electronic speedo on the 90-92 cars. IF you know how to read, take a look at a 90 or newer f-body manual and it will confirm what I am saying. And not a Chilton or Haynes but a factory manual.

I don't know why I bothered to ask a highly technical question about the circuit card of the 90-92 electronic speedometer. You bozo's don't have enough tech skill to diagnose a bicycle much less a complicated piece of electronics.

Cocobolo95, did you join this board just to wow everyone with how smart you are? If you look in Njrfirebirds sig he is most likely working on his 89 firebird which has a mechanically driven yet electronic VSS. The later model 700 used the pressed on reluctor version with a magnetic pickup. I believe the switch was in 1990 when tpi cars were switched to speed density. You can buy an electric vss that sandwiches between the speedo cable if you follow this link http://cgi.ebay.com/ebaymotors/85-89...=p4506.c0.m245 . Seeing as you joined within the last 7days you seem pretty cocky, don't you think?

Just my 2¢, but if a VSS system or even an automotive ECM is a "complicated piece of electronics" then a TFT HMI control must be a bona fide miracle.

Incidentally, my Trans Am VSS has a red plastic gear on it, and it has the optical pulse generator (I have a bit of a clue since I replaced the gear). Later F-Bodies were different in that they used a tachogenerator instead of an optical interruptor, but the part numbers for the gears are the same, so I'd suspect they are the same material. They might be different, but the numbers are the same.

I have a VSS unit from a 1992 Z28 sitting right here.. and what do you know.. PLASTIC DRIVEN GEAR. I also have a factory service manual for a 1990 Camaro and one for 1992 Firebird, and neither one mentions a reluctor ring, they do however mention removing the metal clip to remove the plastic driven gear.

It's more like the fact that you have supposedly been into "hundreds" of these transmissions and yet you can't tell the difference between a 4L60E and a 700R4.



it has a 44 tooth PLASTIC driven gear

And if that's not enough, please PLEASE tell me exactly what is the signal that's output by your supposed 1990 RS transmission with a reluctor wheel on it instead of the correct plastic driven gear??? Because you OBVIOUSLY have no idea how the thirdgen ECMs operate. Also tell me WHY they switched to this newer style.

The two-pulse (2000 pulses per mile) square wave (D.C. current or direct current) used on all TBI engines through 1992, all computer-controlled-carbureted engines, and on 1985–1989 TPI engines.
A four-pulse (4000 pulses per mile) sine-wave (A.C. current or alternating current) signal is required by the 1990–1992 TPI, 1992–1993 LT1 engines, and 1990–1993 Camaro 3.1/3.4 V6 engines.
A 40 pulse per driveshaft revolution speed sensor used on 1993 and newer trucks with automatic transmission, 1994 and newer rear drive cars (Camaro, Corvette, and Caprice) with the automatic transmission.

And just because it amuses me, I'll help you figure out your speedo problem here -
http://www.thirdgen.org/techboard/el...lp-needed.html (Speedometer help needed)

If in fact you actually DID remove the tailshaft and find a reluctor ring, then a previous owner obviously screwed with the transmission, or had it screwed with. Maybe tried using the output shaft from a 4L60E? Just speculation because I've found far too much stupidity from previous "mechanics" working on thirdgens. You've only owned the car for 5.5 years, why you think it must still be a completely stock transmission escapes me.

Anyway, if the VSS was working, as in out putting a signal, it's completely wrong. A 1990 V6 uses a '730 ECM and is expecting a 4,000 PPM ( pulse per mile ) signal. The ECM then out puts a 2000 PPM signal to the speedometer, and a 4000 PPM for the cruise control.
The reluctor ring style outputs at a much higher resolution, which is needed for ABS ( something that NO thirdgen was equipped with further proof that there is no reason any thirdgen would have the reluctor ring) it's 40 Pulses per driveshaft revolution. This equates to like 30,000+ ( rough estimate.. there is a formula if you wish to find the exact number ) Pulses Per Mile. So in fact the problem was not in 4 separate speedometers, but that the wrong signal is being used.

I used my limited knowledge of thirdgens to figure this out for you, and it only took about 30 seconds. I guess working on it for 5 and half years and not figuring it out seems reasonable too though.

Just to beat a dead horse, I have swapped them many of times, from electronic VSS to cable VSS, and it worked every time.

just wanna jump in the mix here....I just bought a t5 with an electric speedometer drive and i have an 86 camaro with a cable speedometer drive 700r4 tranny...what im reading here is that i can simply take the mechanical one off the 700r4 and put it onto the t5??? If not what would i have to do??thankss

Im using a th350 in my 1991 trans am with the eletric speedo still working fine. Im just using a 90-92 tpi retrofit vss 400 pulse adapter.

T-5 to T-5 and 700R4 to 700R4 only. Purchase a T-5 sleeve (speedometer gear housing) and the correct drive and or driven gears if you want the speedo head to read correctly. Here's a link to the sleeve (TH350):

http://www.transmissioncenter.net/sp...____va.htm#350

JamesC

ok...do u know what size drive tooth gear and or driven gear i would need? Im not sure what is there and i also would need the gear housing? #68XX on the site correct?
So i need to buy #68X (the correct drive and driven gear) and #68XX, then remove the electric speedometer drive on the t5 now and replace it with these parts?
Also what do i do about the electrical speedometer drive? what would i need to convert that to mechanical?
Thanks for your help.

With stock tires, the following sticky may provide what you need:

http://www.thirdgen.org/techboard/tr...ve-driven.html (T-5 Drive/Driven Gear Info--Please Contribute)

Replace what's in the trans with the 68XX speedo housing (silver bullet-looking thing) and the 68X correct drive (and may need the appropriate driven gear as well) and you should be good to go. BTW, the 68X gears are for 3.23's up. If you have something besides 3.23's up, you might phone the above company for advice.

JamesC

Cocobolo is a toolbag and makes me laugh.

I have taken a few camaro tail shafts off, cable speedo and electric speedo (90-92 cars, also dubbed just 4L60 NOT E, because of the electric speedo). They all had a plastic gear on the tail shaft held on by a little metal clip, unless of course for some reason that clip broke like the case of my 88.

Great links in this thread!

FYI - my 1992 700R4 had plastic gears as well - no metal gearing pressed on the shaft. And yes, I did take it apart and saw it for myself, since I swapped gears for my LS1 3.42 geared rear end when I swapped it in.

Hlp

where is the Cable located on the transmission. I cant find it. Car is on 4 jacks I can see both sides and even stuck my hand over and around (tail area where plug is, speedo gear, speedo cable right?)the where Vader's picture, Details. I just can't find it,
Please help, Ajuda porfavor, Agua Agua

Your 86 isn't cable driven. Check post 18 for a pic of the VSS.

JamesC

So can you tell me, from the 1986 cars, which ones have a electronic speedo and which have a mechanical 1. and also on my car, on top of trans pan lip passenger side. I see an attached tube and a connector. 1 is the fill tub/dipstick the other is the T.V cable. if this is the same transmission for mechanical speedos where does it connect to and do you have a picture? the 1986 firebird/trans am Service Manual does not show where the speedo cable is attached to but tells you to take it out and replace cable if speedo needle flutters. it does not give you the breakdown on removal like it does for every little thing else(I'm puzzled)
So should I replace the VSS(Little yellow box buy glove pouch?) or replace tranny portion of speedo gears in tail section? and do you think it would be easy for a guy with 17 years of computer repair experience? I get intimidated with repairs on my 1986 TA, because it is hard. I got the service manual but the first time major repairs, take hours if not days. The second time is minutes. I just hate that first time. Thanks..

I believe 82-85 'Birds were cable driven, 86+ electronic. The usual culprit for electronic speedo woes is the VSS.

JamesC

Guys my sons 1991 Formula has a metal reluctor on the tailshaft. The speedometer has not worked since we purchased the car. Trans is original. I have been to the wrecking yards and Napa and all of the 90 and newer cars have the plastic gears and VSS that match what I pulled out.

Is this what I need instead (#70)?

http://www.transmissioncenter.net/sp...__va.htm#4L60E

ive seen a few with the metel gear , i even had one, none of the speedos worked in the two camaros or the firebird.
all of them origionally came out of full size conversion vans . that must be common in vans. wonder why

If you have the metal "gear" your speedo will never work short of a truck buffer box

Its actually a 40 tooth reluctor and has no physical contact with the optical VSS. It should look like this


It was not used for 3rd gens. Most likely the trans was replaced soon before you purchased the car, or a trans shop pulled the switch-e-roo with a 4L60 they had in good condition with a simple tail swap. Late 80's, early 90's trucks and vans commonly had the modern reluctor setup

You need the plastic drive and driven gear matching your tire and rear axle ratio. Then you need a VSS matching your ECM. 90-92 cars use the VSS Jay posted with the side retainers

Use this site to help identify which drive/driven gears you need for an accurate speedo
http://www.transmissioncenter.net/sp...n_______va.htm

Luckily none of the required parts are particularly expensive

i was thinkin it was a truck thing. i had the one in there with that gear , but that one is long gone. just for info, what was the purpose of havin those types?

this is all odd, i have had 6@ 700r4 trainys, from 87 to 91, every one of them have had the metal gear in them. long story short - i put a th400 in. tired of them 700r4's not lasting for hulling a 4x4 bigbear.

i have the problem of no speedometer, long upshifts. the truck i put the trainy in is a 88 chevy 1500 extend cab 2x4 with a 8 foot box. from the factory, it has the full tow package (listed in the paperwork), but it came with the 700r4. i put in a new super duty TBI 350 crate engine, posi 3.73 rear, 28.8 tires. found i need the 7,18 gears, but my truck is a vss, the trainy is cable.

i took the th400 from a 74 elcomeno with 4.11 rear, 26 tires, built up 350 w/4 barral carb.

problem is, i need the vss for this th400. i have looked in a few junk yards with no luck on finding a electric one with plastic gears. the th400 has a green plastic gear on the shaft, i am guessing that needs to be changed, but it is a larger shaft then the th350 or 700r4. i have gone broke fixing this truck up, so i need to find the parts in a junk yard. all the ones i have looked at online is way to much for the th400.

i would like to find one like in post #20, if i can not find the parts cheap enough, i will have to just get my parts machined.

sorry this is long, and for any mis spelt words.

Did any TH400 came with a VSS .
Maybe a late '80's truck w/BBC before they went to 4L80E trans ?

Depending on what pulse signal your TBI computer requires , you fit one of these between speedo drive and cable at trans.
Gives out required VSS signal and keeps mech speedo


http://cgi.ebay.com/ebaymotors/90-92...Q5fAccessories

http://cgi.ebay.com/ebaymotors/85-89...Q5fAccessories

that is a lot of money for that part. i am retired, and can not afford that right now.

there should be a part like in post 20 that would work.
if not, i will just get the tail shaft housing from the th400 and metal gear from the 700r4 machined to work.

i was hoping to find the part in a junkyard, that way i can still get around, slowly but better then walking with a cane. right now i have the th400 parts in it to stop any leaks.

also, a few say the vss does not go through the brain,
in my truck, i get a speedometer code, and the check engine light comes on.
i do not have cruise and it is a 88 chevy c1500 pickup.

The computer uses the VSS signal to adjust revs.When you lift off throttle ,the computer doesn't know if you are cruising or slowing down without the signal so revs may be high when you come to a stop

it does not up shift till about 7500 to 9000 rpms, the 1-2 shift is at about 50 mph, the 2-3 is the same for rpms but at about 80 mph, it idles fine and when i let off the throttle, it idles normal at a stop.

it does kick down soon as i let off the throttle. i do not have the wot switch connected yet, i just got it today. i also just got a speed censer and a modular (the right one), and half a govener kit (from a friend, i hope it has the parts i need). i have changed the modular a few days ago, i got the high vaccume one (20 psi), and my truck is a low vaccume engine (15 psi).

i still need to get the plastic speed gears for my setup.

an update on my trainy problem.

it now upshifts at about 5000 rpms, once it is in 3rd, i have to keep my foot on the pedal or it slows down fast. i ordered the right speedo gears and had a 700r4 sensor machined to fit, the machining cost me a 12 pack of beer

hi i was wondering if someone could help with my problem.i bought a 91 z28 a few months back and the speedo doesnt work.the guy i bought it from said he swapped in a rebuilt 700r4 from his buddys blazer.from looking at it i assume it was a cable driven setup since theres no plug for the vss connector that i found tucked away under there.so from what i read i have to change out the whole setup on the trans or buy some kind of signal adapter?.i just do not have alot of experiance with trannys.im gona try to post a pic of whats on my tranny now.thanks guys

Thats a cable VSS, you can tell by the threads and no connector. Luckily its also a large hole VSS, so all you need to do is swap the sensor to an electric version and match up the gearing for your rear

ok thank you.what do i have to do to match up the gearing though.

The drive and/or driven gears have to match the rear end gearing. Check the stickies in the Trans/Drivetrain forum for more info on exactly what gears you need.

JamesC