15 speed RTO 14615 transmission


Captain504

Active Member
Is the 15 speed RTO14615 transmission good for highway use? What is the transmission’s average speed range ?
 

It's an overdrive transmission running .78:1 in top gear. Max torque is limited to 1450 ft-lbs.

We already discussed this and there are many variables that determine your RPMs.

.78 overdrive means if 1:1 is 2100 RPM going down the highway in your particular setup, then overdrive would kick you down to 1638 RPM.
 
If this is your CAT with the 4.56 rears, it will turn 2100RPM at 66-67mph in high gear if it has 11R22.5 tires.

This is why I was going to put a 13 speed double overdrive in my Ford. The final drive is .62 in the RTOO-14613 and with its 4.44 rears it would turn 1600 RPM at 65-66mph on 11R22.5 rubber.
 
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If this is your CAT with the 4.56 rears, it will turn 2100RPM at 66-67mph in high gear if it has 11R22.5 tires.

This is why I was going to put a 13 speed double overdrive in my Ford. The final drive is .62 in the RTOO-14613 and with its 4.44 rears it would turn 1600 RPM at 65-66mph on 11R22.5 rubber.
2100rpm with OD transmission I didn’t expect that.
I did a full inspection of the truck. Not sure what the previous owner did with this truck.
It surely seems to be set up more like a dump truck vs heavy haul.
 
2100rpm with OD transmission I didn’t expect that.
I did a full inspection of the truck. Not sure what the previous owner did with this truck.
It surely seems to be set up more like a dump truck vs heavy haul.
It's that rear end. It's for digging power down low but kills you on the top end.

These trucks are low on HP compared to today, so they used deep reduction to get moving.

I always joke that my old Ford must have been a dump truck in a previous life. It's only a 9 speed direct. Lol.

My truck is an 88 and interstate speed limits were 55 back then, so it really wasn't a problem.
 
His "B", in front of a 14615, tells me it's probably a 350/375hp. Before you go putting the power to it, you need some real world numbers on what you have. Or you need a driver that won't call you in the middle of the night with the driveshaft on the ground.
 
I wonder what year this truck is and of it was ever rebuilt.

2100 rpm was not a good idea for CAT at any time that I know of.
It'd be pretty old being a b. That was the top engine choice for my Ford. But a lot of folks went with the Cummins because the HP spread wasn't actually that much.
 
Wasn't 1994 the last 'B' mechanical?

Those 4 and a quarters with a tune up would put the late 90's 'E' engines to shame.
 
What was the original purpose of the truck? Do you know? Logging? Road work? Mine work? It's geared too high to be used a lot on the road. The B's liked to operate at 1500 to be happy and pull.
 
What was the original purpose of the truck? Do you know? Logging? Road work? Mine work? It's geared too high to be used a lot on the road. The B's liked to operate at 1500 to be happy and pull.
Not sure.
I am researching that now.
But it does have wet kit with very large hydraulic fluid tank placed beside gas tank
 
The truck was never rebuilt original miles close to 600,000 with hx of trans rebuild. Has a extremely heavy rear axle set up and springs on front and back rear and springs on steers

sorry no pictures
 
I started this post to get a better understanding of the transmission and also help others that had the same concern with the OD 15speed and it’s gearing. I am new to trucking 10 vs 13 vs 15

The 92 W900B low miles and the truck’s original disposition is what attracted me to the truck. The truck starts on first stroke after turning key.

Truck may just be outdated and overweight for a purchase. But compared to newer trucks constant break downs and overall cost. I am looking for a solid dependable truck slow or fast.

Would swapping transmission help with this size truck? Can the OD 15 speed be modified?

I only want to work shipping lanes within a 500 mile range in the south central states. ($2000 to $3000 wkly is the goal) LA, MS, GA etc

With a heavy hauler do I have the options to move lite and heavy loads??

I attached pic of examples of rear end
 

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I started this post to get a better understanding of the transmission and also help others that had the same concern with the OD 15speed and it’s gearing. I am new to trucking 10 vs 13 vs 15

The 92 W900B low miles and the truck’s original disposition is what attracted me to the truck. The truck starts on first stroke after turning key.

Truck may just be outdated and overweight for a purchase. But compared to newer trucks constant break downs and overall cost. I am looking for a solid dependable truck slow or fast.

Would swapping transmission help with this size truck? Can the OD 15 speed be modified?

I only want to work shipping lanes within a 500 mile range in the south central states. ($2000 to $3000 wkly is the goal) LA, MS, GA etc

With a heavy hauler do I have the options to move lite and heavy loads??

I attached pic of examples of rear end
Spring ride. Yikes. 😬
 

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