The Stovebolt Site Forums The Shop Area Driveline How to ID a t5 without a tag, help please

I just bought a t5. The owner said it came out of a 90's s 10. There is no tage so I was wondering how to id it. Is there anyother way without the tag?

I know the casting numbers mean nothing but it does have an electric speedo and a .72 5th gear and a 14 spline input shaft. What year was the electric speedo introduced?
Any help is geatly appriciated.
Rick......

This may help a little link Completely identifying one without tearing it down will be difficult without the tag. I think electro speedo came in the late eighties. Does it have the tail housing with the shifter in the middle or all the way in the back?

Some of the ones in the 90's had a sticker on top that had the number. It would be like 1352-xxx. The elac. speedo started in 88. Like Fan says if the shifter is in the middle its probably an S-10 & if it in the rear its from a Camero. You can tell a World class by the front countershaft brg. The NWC has a smooth surface brg & the WC is recsessed a little.

Thanks for the help. This is a start. The shifter is up front and the brg cap indicates a NWC out of an s10. Feel free to add additional comments.

Rick........

Rick,The tags are usually covered up by gunk and greese.
Here is a picture of where my tags have always been.
ID Tag


Tim

If by chance the metal tag and also the upc sticker have been removed from an S10 T5 transmission, it's fairly easy to determine it's gear ratio and approximate year of origin.

The gear ratio is the big factor. A mechanical speedo T5 will have the speedo insert horizontal to the ground while the electronic speedo lines up at an angle slightly up and pointing at the center of the output shaft. Mechanical speedos typically came in S10 T5 boxes up to about 1989 but check the position of the speedo insert in relationship to the output shaft just to be sure. To determine the gear ratio with the transmission out of the vehicle:

1. Put the transmission into 5th gear by shifting from the neutral slot all the way to the right and forward. Turn the INPUT (front splined shaft)a full 360 degree revolution and the rear (OUTPUT shaft) will turn something LESS than 360 degrees. It's HOW MUCH LESS than 360 degrees that will tell you which ratio box you have.

2. Make a mark on the input shaft at a position we'll call 12:00 or "zero" degrees and a similar mark on the OUTPUT shaft at the same 12:00 or "zero" degrees.

3. Rotating the INPUT shaft clockwise 360 degrees while watching the output shaft rotate. The output shaft won't rotate a full 360 degrees.

4. If the output shaft rotates LESS THAN 270 (9:00 position)degrees your 5th gear ratio is .72 and you have a box with a 3.76 1st gear. NOTE BELOW: (See #6 for exception.)

5. If the output shaft rotates MORE THAN 270 degrees you have a box with a .86 5th gear and with a 4.03 1st gear.

6. If the transmission has a tilted rear mount pad and you turn just a little more than 180 degrees you've got a .63 OD T5 probably out of a Camaro and the shifter is all the way to the rear. Check out the tech tip on "Hybrid T5's to prep one of these boxes for your truck.

7. In addition to checking out the gear ratios you also need to be aware that the Ford T5 bolt pattern is different from the S10 pattern so make an impression of your bell housing bolt pattern in cardboard and check this first at the salvage yard.

As a quick "rule-of-thumb" I've found that an BW T5 box that has the output shaft rotating to about the 7:00 position is a .63, about the 8:00 position a .72 and about the 10:30 position a .86.

Another thing I've found is that the vast majority of salvage yard transmissons AREN'T properly ID'd so you'd be well advised to make a couple little marks.....spin and count the shaft rotations, check the speedo insert angle as well as the bellhousing mounting bolt pattern before you plunk down your cash.

Hope this helps you avoid getting a box that doesn't fit your driving and gearing needs.

Dave

BTW......I could have checked 20 T5 transmissions in the time it took to write this ditty. Try it....it's easy and applicable to most any piece of machinery that is geared.

I just checked my T5 to verify the gear ratios and I think this thread needs to be updated.
If I follow the instructions above, when I am in 5th gear the output shaft (the shaft connected to driveshaft) will turn more than 1 time for the 1 (360 degree revolution) of the input shaft (the shaft connected to engine).
This indicates that the output shaft (the shaft connected to the driveshaft end) must be the one turned the 1 (360 degree) revolution-NOT the input shaft (the shaft connected to the engine) so that you can easily see the gear ratio.
This is in line with general gear formulas for gear ratios which are stated generally as driven gear revolution/s divided by one drive gear revolution.
This means the transmission input shaft should be considered the driven shaft (motor drives it) and the transmission output shaft should be considered the drive shaft (as it is commonly called)
So the correct formula for determining the gearing of a T5 transmission can be found by the number of input shaft revolutions (driven shaft) divided by one output shaft (driveshaft) revolution.

Since it is generally accepted that gear ratios are based off of a 1 in the denominator, a 3.8 gear ratio is actually saying 3.8 revolutions divided by 1 revolution. What revolutions are we talking about? We are saying that
the 3.8 to 1 ratio is 3.8 revolutions of the input shaft (driven) in the numerator divided by the 1 revolution of the output shaft (drive) in the denominator of the ratio.

So, for my transmission in first gear:
If I turn the output shaft 1 time around in first gear, my input shaft rotates about 3.8 times around indicting my expected gear ratio for first gear.
Looking at it the other way:
Gears are devices to lever mechnical advantage through ratios. If you spin the input shaft about 3.8 times with the engine (in first gear) you will get only 1 full turn of the output shaft. You have gained 3.8 times the mechanical advantage from the transmission to get the car going from a stop by putting it in first gear.

Now let's look at my overdrive situation:
If I turn the output shaft 1 revolution in fifth gear (overdrive), the input shaft only turns about .7 times around. This is in line with my expectation of a .72 5th gear overdrive ratio.
If you spin the input about .7 times in fifth gear overdrive you will get one full revolution at the output shaft indicating and over drive condition.
As the formula says about three quarters of the way around on the driven shaft (lets call it .7 of the way around) divided by the 1 full revolution I get from the output driveshaft gives you your .7 to 1 ratio.
To clarify the overdrive, if you are in 4rth gear, for every 1 revolution of the input shaft you will get exactly 1 revolution of the output shaft, you are getting no overdrive. This is a 1 to 1 ratio.
But when you go to fifth gear we know that each .7 partial revolution of the input shaft gives you a full revolution of the output shaft. So in 5th gear, you spun the input shaft less than you did when you were in 4rth gear but you still got the full revolution from the output shaft. So you are in an overdrive condition-less engine/input shaft revolutions when in 5th gear to get the same distance traveled as in 4rth gear.

These links from my website should help.
How to determine T5 gearing

T5 ID tags and markings

T5 INFO PAGE