difference between transmissions

[davedv]

does anyone know the differences between a 16713, 16913, 18913, and a 20913? those r all rtlo trans. if so what r they we have a 1984 pete 362 that has a bad trans. the id plate is gone off of it. i want to replace it with one that has the lowest final ratio as possible to get better fuel milage

 

[Road Dust]

Racer????

 

[davedv]

huh?

 

[Road Dust]

Sorry, he is a member on here, with mechanical knowledge, who might be able to answer your question

 

[bigyellowpete]

I believe you can find the info you are looking for here: Eaton Fuller 13-Speed Transmissions

 

[davedv]

thanks yellow pete that was exactly what i was looking for

 

[bigyellowpete]

Glad I could help.

 

[Racer X 69]

That's what I would have done, Googled it, and then linked it for you.

I am happy to provide help and answers here, but often times a quick Google search will get an answer much more quickly.

Thanks to Pete for getting it done.

As for the final ratio, I believe they pretty much all are "overdrive", I have been told numerous times that there are very few "direct" ratio output 13 speeds.

View attachment 2653

This picture shows what the parts of the number mean.

Based on the information given, 16713 is a 13 speed with 1600ft lb nominal torque capacity, 16913 is a 13 speed with 1600ft lb nominal torque capacity, 18913 is a 13 speed with 1800ft lb nominal torque capacity, and 20913 is a 13 speed with 2000ft lb nominal torque capacity. They all have 0.73 final drive ratios according to the web page linked to by Pete. The differences are the nominal torque capacity and the gear ratios below 7th gear.

The best way to get an improvement in fuel economy is with taller differential gear ratios, but you reach a point of diminishing returns because there is a trade off with the application of torque to get the truck and load moving (depending on the lower gear ratios), and then keep it moving efficiently. You also need to consider the terrain the truck will be traveling over. Mountainous terrain requires different gearing than primarily flat terrain, and there will be trade offs there as well. And then there is tire rolling diameter to consider. And is the truck always going to be loaded to at or near gross weight, or will it be hauling lighter loads more often?

I have mentioned before there is another guy on here who has a tranny shop, and knows a considerable bit more than I do when it comes to these transmissions. Here is a link to his profile: View Profile: JM Transmissions - Truckers Forum