Lets Talk Transmissions 9 10 13 15 ETC

Money is probably the main factor
9 ,13,18 s of the same rating have the same basic main box the difference is in the aux section
9 is just range change
13 range change + split top 4
18 range ghange = split all
the 10 and "15" share the same basic main
10= 5 low+5 high range
"15"= 2 deepreduction +5low+5 hirange (there are 5 in deepreduction but they over lap low
8LLs apear to be 9/13main with a deep low
super 10= 5speed all split
in another post on here ilinked to the road ranger HD manual which shows the ratios and how to read tags
some fleet trucks were ordered with convertables9- 13s with out splitters
for better resale cause we all know that accountants know best
In my arogant opinion if fuller made a real 15 and split the top 10 they would build the ultimate transmission but since most trucks are fleet ordered that will prolly never happen

 

What do you haul?

 

Longhood, 8LL's are basically the same as a 15 but with a 9 spd pattern. I agree on the fact that a 8 or a 15 that you could split the top gears would be very nice. All I drove for a long time were 15's and 8LL's and sometimes I still miss them.
89 Pete, 9 and 10 spd trans were really for highway trucks because they usually don't need the deep gears to get heavy loads moving and they're simpler,lighter and better on fuel when spec'd right. If you do some off highway work the 15's are a nice compromise as they are almost bulletproof and have the deep gears to get you moving.

 

yea I have an 15spd over in my 85 Log Truck.....nice probaly can pull the trees directly out of the ground in first gear deep reduction

 

You guys run alot of 15 up that way

 

The nice thing about a 15 speed in a work truck (logging, gravel, etc.) is the ratios between the two top gears. You can run in top gear when empty, drop a gear when loaded plus that deep reduction for starting in adverse off road situations.

 

I'm just curious which 15spd you are using that you like the top two gears.The RTO has the biggest difference between the top two 1.00-.79 but the 1st gear in deep reduction (13.31)is not as low as a 18spd.(14.40).If you are using the RT you have a deeper first gear (16.94) but not so much on top.Also niether 15 is available with a TQ. capacity of an 18.

 

I would spec an particular trans. dependant on what type of work I was doing,but having engines with the bigger torque rating will limit your options at 1800 ftlb.s and up