Speedometer cable 90* adapter

The TKO II I installed has the speedometer outlet on the driver's side of the transmission tailhousing, this is opposite what I previously had. The TKO II speedo outlet put the speedometer cable right up against the exhaust pipe, needless to say it only lasted a few days before it self destructed from the heat and severe bend in the cable. The solution? a 90* speedometer cable adapter. These are available in 1:1 ratios as well as +/- ratios to allow for different tire sizes. Prices range from $35.00 to $90.00.
They are available from most manual transmission suppliers, suncoast conversions, eckler's and of course - fleabay.
 
thanks thats useful info!

reading thru these links might help, as they contain a wealth of info related to getting the speedo gears correctly set up

http://webpages.charter.net/khastin...charter.net/khasting/techinfo/speedocalc.html


http://www.bgsoflex.com/speedo1.html

http://www.tciauto.com/tc/speedometer-gear-calculator

http://www.thirdgen.org/techboard/faq-b ... -gear.html

http://sethirdgen.org/t5speedo.htm

http://www.transmissioncenter.net/speed ... ____va.htm

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

http://www.5speeds.com/t5/

http://www.73-87.com/7387garage/drivetrain/spdgears.htm

http://www.geocities.com/crosley_az/700spd.htm

http://www.partshp.com/speedometer_gears.htm

http://www.summitracing.com/search/?key ... ars&page=2

http://store.summitracing.com/egnsearch ... 15+-157862

http://www.ecklers.com/product.asp?pf_i ... pt_id=1783

http://www.corvettetraderonline.com/sto ... uctid=1925

http://www.corvetteparts.com/catalog/0204054/1.htm

http://www.transmissioncenter.org/speed ... ousing.htm

speedometer_calibration_______va_htm_txt_SGear.gif


http://corvetteforum.net/c4/vettenuts/S ... shtm.shtml
c4sps1a.png

c4sps2a.png

c4sps3a.png

c4sps4a.png
 
Last edited by a moderator:
DeeVeeEight said:
Here's another one

http://www.transmissioncenter.net/speed ... ____va.htm

sorry - same place, different link....
http://corvetteforum.net/c4/vettenuts/S ... shtm.shtml
c4sps1.png

c4sps2.png

c4sps3.png

c4sps4.png


ALL INFOS USEFUL! THANKS FOR POSTING!
BTW on occasion you'll find a speedometer needle that vibrates or a speedo that clicks annoyingly

on most speedometers theres a cable between the gears in the transmission and dash gauge thats spinning in a flexible metal tube, if you slide the cable out of the tube and lube it with a thin drippy slurry mix of moly grease and oil, then slide it back in, it cures that clicking which results from it partly binding during its rotation
yes it will in must cases slide out the problem is that in some cases the cable only slides out from the dash end, IF you find thats the case one old trick is to carefully tape the end of the grease gun to the cable with a few inches of rubber hose between the two and clamped in place temporarily then give it a few shots of grease, the problem with this is that if you get a bit generous it can leave grease dripping from under the dash or a non-functioning speedo, so yeah, disassemblys preferred

molygrease.jpg


Core (the part inside that turns) can be removed from one end of the sheild (casing),- and lubricant applied to core along full length, and maybe a small amount put inside open end of cable shield... Then core inserted back into core, - turn a little at finish to make sure it engages in other end (if only one end of "cable" disconnected). Hook end back up and you are finished!

"White grease" is nice if you have it handy, - but regular "wheel bearing grease" wil be fine! Or I think you can buy a special grease at parts store for this purpose, -- (but it will cost more). I have been just using WB grease for more than 50 years, and had no problems with lubricant! Note here also that one end of cable has a "gland" or flange on core, so it will not drop into shield too far and then not reach the fitting to be turned at connection! --- Generally this is at top end of cable, so it needs to be removed from speedometer to get out! But this is not steadfast rule - though it is the sensible way to do it, so it does not drop down far enough to not engage speedometer head connection! I always start at transmission and see if the cable will "pull" from that end though,- as it is easiest to get to! ... "Dry (no lubricant) speedometer cable" gives a sort of "jumpy" action of speedo needle at slower speeds, - possibly "vibrating" a small amount at higher speeds!

Now if it is a "growling", - or sort of "screeching" noise that happens intermittently, and seems to be from speedometer area, - then it might be bearing in speedo head, - Which can be lubricated with speedometer cable unplugged (with head out of dash). This requires a certain type of oil, and it is best to get specific oil for this purpose!
Source(s):
old mechanic

http://delorean2109.blogspot.com/2008/0 ... meter.html


naj posted this info
Way back in the day the cable could be removed from the casing.
You used to be able to buy a universal cut to fit cable with ends you would crimp on.
They also used to sell a graphite lube to lube the speedo cables.
Unfortunatly it has been almost 20 years since I have done this so I do not know anymore.

Service and Repair
The following material covers only that service on speedometers which can be performed by the average service man. Repairs on the units themselves are not included as they require special tools and extreme care when making repairs and adjustments and only an experienced speedometer mechanic should attempt such servicing.
The speedometer has two main parts: the indicator head and the speedometer drive cable. When the speedometer fails to indicate speed or mileage, the cable or housing is probably broken.

SPEEDOMETER CABLE
Most cables are broken due to lack of lubrication or a sharp bend or kink in the housing.
A cable might break because the speedometer head mechanism binds. If such is the case, the speedometer head should be repaired or replaced before a new cable or housing is installed.
A "jumpy" pointer condition, together with a sort of scraping noise, is due, in most instances, to a dry or kinked speedometer cable. The kinked cable rubs on the housing and winds up, slowing down the pointer. The cable then unwinds and the pointer "jumps."
To check for kinks, remove the cable, lay it on a flat surface and twist one end with the fingers. If it turns over smoothly the cable is not kinked. But if part of the cable flops over as it is twisted, the cable is kinked and should be replaced.

LUBRICATION
The speedometer cable should be lubricated with special cable lubricant every 10,000 miles.
Fill the ferrule on the upper end of the housing with the cable lubricant. Insert the cable in the housing, starting at the upper end. Turn the cable around carefully while feeding it into the housing. Repeat filling the ferrule except for the last six inches of cable. Too much lubricant at this point may cause the lubricant to work into the indicating hand.

INSTALLING CABLE
During installation, if the cable sticks when inserted in the housing and will not go through, the housing is damaged inside or kinked. Be sure to check the housing from one end to the other. Straighten any sharp bends by relocating clamps or elbows. Replace housing if it is badly kinked or broken. Position the cable and housing so that they lead into the head as straight as possible.
Check the new cable for kinks before installing it. Use wide, sweeping, gradual curves when the cable comes out of the transmission and connects to the head so the cable will not be damaged during its installation.
If inspection indicates that the cable and housing are in good condition, yet pointer action is erratic, check the speedometer head for possible binding.
The speedometer drive pinion should also be checked. If the pinion is dry or its teeth are stripped, the speedometer may not register properly.
The transmission mainshaft nut must be tight or the speedometer drive gear may slip on the mainshaft and cause slow speed readings.

related thread

viewtopic.php?f=33&t=680&p=944&hilit=+speedometer#p944
 
For future reference, here are the PNs for the all plastic T-5 speedo gears:
Teeth PN Color
18 3987918 Brown
19 3987919 White
20 3987920 Blue
21 3987921 Red
22 3987922 Gray

The gears are about $5.50 each

heres some rather random but useful related links

http://webpages.charter.net/khastin...charter.net/khasting/techinfo/speedocalc.html

http://garage.grumpysperformance.co...r-gears-at-the-transmission.12179/#post-59006

http://www.transmissioncenter.net/speed ... ____va.htm

http://www.classictransmissionsolutions.com/th350-turbo-350/

http://www.transmissioncenter.net/speed ... .htm#4l80e

http://www.bgsoflex.com/speedo1.html

http://www.summitracing.com/search/?key ... ars&page=2

http://www.tciauto.com/Products/TechInf ... _gears.asp

http://www.teraflex.biz/tech/faq/speedo ... ear-chart/

http://www.teufert.net/trans/speedo.htm

https://www.hotrod.com/articles/calibrate-gm-mechanical-speedometers/

http://www.speedometershop.com/ratio.html

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

http://www.automedia.com/Changing_Your_ ... 020501sg/1

http://www.73-87.com/7387garage/drivetrain/speedo.htm

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

Here is a list of GM part numbers for drive and driven speedometer gears, as well as some combinations that are known to work:


Driven Gear and Sleeve PN's

Part No.
9774413
9780387
1359270
1359271
1359272
1359273
1362048
1362195
1362049
1362196
9780470
9775187 Teeth
34
35
36
37
38
39
40
41
42
43
44
45 Color
Lt. Green
Orange
White
Red
Blue
Brown
Black
Yellow
Green
Purple
Dk. Gray
Lt. Blue Sleeve
25512340*
25512340*
25512340*
25512340*
25512340*
25512340*
25512339**
25512339**
25512339**
25512339**
25512339**
25512339**

* Sleeve #25512340 for 34 - 39 teeth gears
** Sleeve #25512339 for 40 - 45 teeth gears

Blue Drive Gear Combinations

With drive gear number 8640518, (blue, 18 teeth) the following combinations apply: (The 18 tooth gear I had in my 85 C10 was green, they changed the color to blue)

Axle Tire Dia. Driven Gear
Ratio (Nominal) (Tooth Count)
2.73 29.0 35
2.73 28.0 37
2.73 27.0 38
3.08 29.0 39
3.08 28.0 41
3.08 27.0 42
3.23 29.0 41
3.23 28.0 43
3.23 27.0 44
3.42 29.0 44
3.42 28.0 45

Red Drive Gear Combinations

With drive gear number 8640517, (red, 17 teeth) the following combinations apply:

Axle Tire Dia. Driven Gear
Ratio (Nominal) (Tooth Count)
3.08 29.0 37
3.08 28.0 39
3.08 27.0 40
3.23 29.0 39
3.23 28.0 41
3.23 27.0 42
3.42 29.0 41
3.42 28.0 43
3.42 27.0 44
3.73 29.0 45

Gray Drive Gear Combinations

With drive gear number 8642620, (gray, 15 teeth) the following combinations apply:

Axle Tire Dia. Driven Gear
Ratio (Nominal) (Tooth Count)
3.08 27.0 35
3.23 29.0 35
3.23 28.0 36
3.23 27.0 37
3.42 29.0 37
3.42 28.0 38
3.42 27.0 39
3.73 29.0 40
3.73 28.0 41
3.73 27.0 43
4.10 29.0 44
4.10 28.0 45

Lower ratio (higher numerically) rear or smaller diameter tire requires higher driven gear tooth count. Increasing or decreasing driven gear tooth count by one will usually accommodate a 1/2" to 1" change in tire diameter.

http://www.73-87.com/7387garage/drivetrain/spdgears.htm

http://sethirdgen.org/t5speedo.htm
 
Last edited by a moderator:
Patro46 said:
After researching the few options for those of us that are performing a retro-mod involving a computer controlled 4L60e transmission into a C3 Corvette, the first thing I realized is there is very little information on this subject. Seems this fancy overdrive transmission with it's overdrive, capable of breathing new life into old technology has a few pitfalls of it's own that your going to have to address sooner or later. I put it off as long as I could. By far, the largest obstacle to overcome is how to drive that large, sexy speedometer as our C3 speedometers are driven by a mechanical cable, and not electronic like today's speedometers. Case in point is what is on the 4L60e transmission that takes the place of a mechanical speedometer drive. Welcome to the VSS sensor.
20140531_003332_zpstwdf0ocx.jpg



This basically consists of a 40 tooth reluctor wheel and a magnet, something not capable of driving our mechanical speedometer. Also note, for an LSx/4l60e swapthe VSS sensor is needed for things other than an electronic speedometer, namely the engine and must be kept as such.

Now that we've covered the directive, let's look at the options. One company, Dakota Digital makes a box that takes the VSS signal and drives a physical electric motor that in turn drives your speedometer cable. It can be mounted either under the dash or probably preferably, in the engine compartment.
DakotaDigital_zpscc5f18c8.jpg


Though this would clearly cure the problem, I didn't want to have to rely on an electric motor, something that has a much shorter suggested life anticipation than a good old tried and true ring and pinion gear driven by a transmission tailshaft.

This said, it leaves us with just two more options. Start drilling, cutting and welding the 4L60e tailshaft housing to make room for a shaft driven speedometer gear or get one of these.

20140531_003730_zpsxxzj7tfs.jpg


This bolts directly to the transmission, using the 6 provided longer bolts. Note the threaded area for GM VSS sending unit. With a reluctor wheel change and relocating it further upstream it allows us to use this for the mechanical speedometer drive.
20140531_003741_zpsaldmxftd.jpg


This tailhousing, I believe, is from a 700r4. It's quite a bit shorter than the tailshaft housing of a 4L60e

20140531_003806_zpsdy6bk8do.jpg


But with the VSS spacer block added, it brings us right back where we need to be.

20140531_003944_zpshmyvsszf.jpg


Here is a view of the transmission output shaft. the reluctor wheel will have to be moved towards the transmission, and the plastic ring gear will take it's place to drive the speedometer

20140531_003610_zpstylbpnvp.jpg


Here you can see the spacer block that uses all 6 bolts to secure it to the transmission, and has four threaded bolt holes to bolt the 4 bolt, 700r4 tailshaft housing to the adapter block.

20140531_004226_zpsiq4lzi5i.jpg


I did a little math and figured the teeth on the ring and pinion using the rear end ratio and tire diameter formula, so the speedometer should read pretty close to actual.
20140531_003535_zpsngomcked.jpg


When the sensor and reluctor wheel come in, I'll complete the thread. :thumbsup:
I've had to order the VSS sensor, as well as an oversize 40 tooth reluctor wheel.

http://www.bowtieoverdrives.com/index.shtml

http://www.bgsoflex.com/speedo1.html
 
Last edited by a moderator:
Back
Top