how do tell the ratio of lenco or b&j trans

Hi with out tearing them apart. Or with out and numbers or letters stamped on either trans. Thx

 

You got to take it apart and count the ring gear,sun gear,planet gears of each section.then can look up ratio chart to check your findings to determine whats inside it.Dont think theres another way sorry.

 

I have never tried it but can't you just turn the input shaft the forward direction and count the turns of the input shaft versus the turns of the output shaft? For second gear shift it and repeat?

 

It would be very difficult to do accurately-the ratio can be very close ex. 1.61to 1.64 1.67 1.71 and so and so when you take a lenco appart the ratios are on the gearsets

 

If you are just looking for an estimate the turn the shafts deal will work. Mount a pointer or trigger switch to the output shaft & a degree wheel to the input. The difference between a 61 & 64 is about 11 degrees at the input shaft. Of course by the time you got the set-up done you could have taken it apart...

Chris Saulnier Team Tigges
Mechanic Falls, Maine

 

You can do it by turning. It's easier if you turn it 10 times (or more) and count the number turns on the output. Then just divide input/output. More turns will give you a more accurate partial turn estimate. Break your partial turns out into clock time with each hour being .08334 of a turn. If it's a 3 speed or more, lock the other 2 or more sections in gear (1/1) to get an individual section ratio. Conversely, you can leave the other sections disengaged and get the combined ratios. Should get you pretty darn close.

 

I would suggest simply using a magic marker marking the input and output shafts and then turning it ten times through on the output shaft as others suggested and averaging the numbers. Should be very close. I would not try the degree wheels. By the time you rigged all that up, you COULD take it apart.

 

Thx mike. Is there a utube video onbthis

 

Thx mike is there a utube video on this by chance

 

Another easy way if you have good data to go from is to do a simple calculation using your data in each specific gear..

Divide your Clutch RPM by your DS RPM

Clutch RPM
DS RPM
= Trans Slip (Ratio)


example.
Clutch RPM at any given time in first gear say, 1.3 seconds is 7845
DS RPM at same time chosen as Clutch RPM is 4783

7843/4783= 1.64 - this is your first gear ratio

Repeat for any instance you know you are in second gear, i.e 3.6 seconds
Clutch Rpm is 8105
DS RPM is 6326

8105/6326= 1.28


Just an easy way that i have found ripping gear box apart