18 Speed Splits

I have been into many a 13 speed before. The reason they tell you not to use the hidden hole is that the oil slinger will not lubricate properly in high range ( according the eaton service manual ) But I have had a couple good transmission guys show me the real reason. The lower shaft that that low range gear is on is not near as heavy as the upper shafts. When you are in low range the gear is forward and the load is on the gear. when you go to high range the gear moves, and puts too much stress on this shaft. If you ever looked inside a 13 speed or 9 speed, you would see the bottom left shaft looking at it from the rear is about half the size of the other shafts. I am not a transmission or gear guy, but what I was shown as I asked why can't I use he low hole. If you have never had the pleasure of going into a Roadranger you are lucky. There are timing marks on the front gears for the output shaft. One tooth off and you get to start over.

 

I have a hard time figuring it in a modern RTLO since the auxiliary box is an under drive, one way the gear is a lower ratio if I use the percentage to the low split in the high side, but if I go off of the base gear set that would be the same as the 9spd main box then it is just slightly faster than 5L.

I had figured it on an older RTO and it does fall between 4 and 5 ratio wise.

 

You may be correct smokincat. Whatever the reason..... Oil slinger, small shaft or whichever, I probably shouldn't be using that gear.

 

You still have the K100 in the barn, think it was red...?

 

I've done it once or twice in a logger cause I was bouncing around in the cab.We don't wear seat belts off road and we don't lock the doors. It does work as a half step gear. I have heard the same about the small shaft. Not recommended.

 

We have one 18 speed and one 15 speed. I never use it on the 18, but it is fully progressive on the 15 and needs to be used in order to maintain the proper splits.

I know nothing about the internals of a transmission, but I assume that the 15 speed is built to use it. Is this correct?

 

Yes correct. 15 speed you have to use that hole and was designed that way.

We are talking about 13 and 18 speeds here . That hole is for low range only on these trans. Not recommended as a cheater gear in high range .

 

Your 15 is based on a 10spd main box so yes that would be normal.

 

Have three now, my 79(red), the 83(maroon) and probably the one you remember, and a 85 aerodyne now.

 

All Cat power?