VSS testing

[wayne petty]

http://www.transmissioncenter.net/speedometer_calibration_______va.htm

just for the info...

[Okiedokie]

Thanks Wayne, darn near have that site memorized. Didn't give me a clue as to why I have the problem, or at least I missed it. LOL.

[wayne petty]

wait... look at the insert..

you have the ability to ROTATE the insert to engage the teeth..

different rotation positions for different gear diameters..

look at the edge of the insert.. sometimes there will be numbers..

there will be hash lines.. to stop at the various known positions...

i must be thinking of a DODGE transmission.. sorry

when you insert the driven gear holder.. can you use a tiny screw driver to see if the driven gear is actually engaging the drive gear inside......


wait again.. they use different driven gear housings to space the driven gear away from the drive gear..

#54. 700R4 Speedometer gear housing for 40 to 45 tooth driven gear (aluminum not plastic)


#54. 700R4 Speedometer gear housing for 34 to 39 tooth driven gear (aluminum not plastic)

must have a sightly different centerline...

so does the gear engage when you insert it in the tail housing.??

but . then you have a Speed sensor...  i think there are 2 part numbers for that..    can you use a magic marker to place a single stripe on the driven gear..  insert the housing with the stripe straight up..  then turn the drive shaft 1 turn.. take it out and look at the position of the stripe...

did it move any.. ?? perhaps a quarter turn..


#55X. Speed sensor for above 34 to 39 tooth driven gear. (Black) $89.00

Qty

#55XX. Speed sensor for above 40 to 45 tooth driven gear. (White) $69.00

Qty


since you have a 39 tooth driven gear..   if you have a 40 to 45 tooth speed sensor.. the smaller diameter gear MAY not touch the driving gear.. and you will have NO movement..

can you use a magic marker to mark ONE of the drive gear teeth so you can turn the drive shaft to count the teeth on the drive gear.. the picture in the cut away is light green like you have described.. but it may not be available.. so that might be where there are NO part numbers for it..

[enjenjo]

Just out of curiosity, is the boss for the driven gear centered in the adapter housing? there are some for older transmissions that are like Wayne mentioned, you have to index the housing to the gear used. I believe they will fit in the same hole in the tailhousing. Or your gear does not match the adapter housing you have as Wayne mentioned.

[wayne petty]

i don't recall what speed sensor you have...

34 to 39 teeth.. use speed sensor

GM 25007224

this seems to be a white sensor

http://contentinfo.autozone.com/znetcs/additional-prod-images/en/US/wl2/SU1010/14/image/4/



40 and up

use speed sensor

gm  25007308

i don't see a decent picture of the black version other than from the transmission sensor link...


1990-1984 All Corvette (w/Option D9B) 25007308 Tomco# 31018

1990-1984 All Corvette (Trans Mtd w/Option 9DA) 25007224 tomco #31019


http://www.tomco-inc.com/Catalog/vehicle%20speed%20sensors.pdf

so.. what color is your speed sensor.. white  or black?

[Okiedokie]

GM 25007224 is the sensor I have, except where this one is white, mine is black.

[wayne petty]

found this

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



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.

[oj]

I am doing about the same thing, i just wired the sensor this afternoon.  Mine came from American AutoWire in a autometer gage kit.  
It was spefic about twisting the ground and signal wire (i used my battery drill) and that the +12v supply needs to be run seperatly.  I ran them in 2 different tarred fabric conduits.  
There is another signal ground wire from the gage that needs to be grounded independantly of the gage light and power ground.
My signal generator may be different from yours, i have the three wire unit.

[Okiedokie]

oj, isn't the three wire sensor to be used with as a replacement for a cable style sensor? Wayne, is the black sensor you referred to the same as the one pictured only black where that one is white?

[Crosley.In.AZ]

on a side note,  I have these old speed-o parts setting around.

[wayne petty]

ok tony...

can you face the shaft end toward the camera...

or measure the slight offset..

perhaps...   measure the height of the gear teeth off the work bench when the sensor is held straight..  

or line them up side by side... for a comparison..

there must be a tiny difference in the centerline of the shaft ... to make up for the different sizes of the gears used..

so the gears actually mesh..  when the sensor inserted..

[Okiedokie]

Thanks Tony, the one on the right is what I have, with the brown gear.

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[Crosley.In.AZ]

The gear on the out put shaft is just as important.  Many folks use a T-350 gear on the out put shaft.  The plastic T-350 speed-O gear fits fine, it is not the correct diameter as a proper 700r4 gear

[Okiedokie]

Once again you guys willingness to share your knowledge has gotten me over a hurdle. Wayne's comment about seeing the shaft end of the sender prompted me to look, sure enough it was offset to one side. I went to a local long time transmission supply business today and got a 43 tooth gear. Problem solved. The sender I have is for the 40 and up tooth count gears. Why the guy that rebuilt the trans [an old time well respected builder] gave me the 39 tooth gear I have no idea. Just an oversite I would guess. Anyway I now have a working speedometer thru the ecm which adds even more value to your help. By the way Wayne, using ejenjo's idea on a p/n setup I now have idle air counts for the first time. Thanks to all for your input. Joe