doubleclutchinweasel

I have some part numbers. But, I have no descriptions (i.e.: tooth counts). Direct Drive (RT-910, -915) Input Drive Gear - 14486 Countershaft Driven Gear - 14303 Countershaft 4th Gear - 14299 Mainshaft 4th Gear - 14487 Overdrive (RTO-910, -915) Input Drive Gear - 16601 Countershaft Driven Gear - 16003 Countershaft 4th Gear - 14303 Mainshaft 4th Gear - 16002 If anybody has the tooth counts on these, and knowing what the 1-2-3 ratios are, I think we can accurately chart the effective gear ratios of a home-made RTO. All the rest of the gears appear to be the same. Any info?

You're all over it! We're currently trying to figure out exactly what the gear ratios would be after doing that. I hope I can find the tooth count in a direct & see what the resulting ratios would be in the homemade od box.Incidentally, you are exactly right. We should always assume a new guy is reading this. That's why I'm frequently guilty of providing more than just a short answer.

I'm not saying that swapping the front gears with the 4th gears is necessarily the same thing as getting a "real" overdrive box. All I'm saying is that, by swapping those gears, you are speeding up the countershafts, effectively raising every gear ratio about 20%. The steps in-between gears will not change, as they are determined by the ratio of teeth on each gear set. Of course, if any steps ARE affected, it would be one step to either side of "direct"...and that COULD be a real nuisance! If someone will get me the number of teeth on all the gears in a standard RT-910 or -915, I'll be more than happy to calculate the ACTUAL gear ratios achieved by doing the gear-set swap. Or, would the number of teeth be in the parts book? I'll look and see if I may already have those numbers. Incidentally, this is fun!

O is overdrive. X is overdrive with pattern "fixed".

Sorry... the "T" is for "twin countershaft". Stepped out for a moment there...

According to the Fuller service manual... 15-speed direct Deep Reduction R - 13.03:1 1 - 12.0:1 2 - 9.42:1 3 - 7.45:1 4 - 5.90:1 5 - 4.78:1 Low Range R - 8.73:1 1 - 8.05:1 2 - 6.30:1 (22%) 3 - 4.99:1 (21%) 4 - 3.95:1 (21%) 5 - 3.20:1 (19%) High Range R - 2.73:1 6 - 2.51:1 (22%) 7 - 1.97:1 (22%) 8 - 1.56:1 (21%) 9 - 1.24:1 (21%) 10 - 1.00:1 (19%) 15-speed overdrive Deep Reduction R - 10.55:1 1 - 9.73:1 2 - 7.62:1 3 - 6.03:1 4 - 4.78:1 5 - 3.87:1 Low Range R - 7.06:1 1 - 6.51:1 2 - 5.10:1 (22%) 3 - 4.07:1 (20%) 4 - 3.20:1 (21%) 5 - 2.59:1 (19%) High Range R - 2.21:1 6 - 2.04:1 (21%) 7 - 1.59:1 (22%) 8 - 1.26:1 (21%) 9 - 1.00:1 (21%) 10 - 0.81:1 (19%) Swapping the drive gears changes the speed of the countershafts. The spacing between gears is determined by the relative number of teeth on the various gear sets.

I've said it before, and I'll say it again; PEOPLE SUCK!!!

At least he falls into the intersection of the sets containing all good things!

Therein lies the problem, doesn't it? The speeds are there, but the torque isn't.

My truck has 4.17 gears, and a direct-in-high trans (1:1). It will cruise at 55-60. 62-63 is about all she wrote. But, 60 isn't too bad. So, let's call this one a 60 mph truck. Depending on the overdrive ratios, of course, a single overdrive (lets call it 0.84:1) will get that 60 up to about 70. A double overdrive (like 0.70:1) will reach about 85...in theory!

Okay! This is one of the funniest things I have ever seen in my life. Somebody put a ton of thought into this one. Those of us of...uhh...a certain age...will get a real kick out of this!

Hey! I changed the scheme from "stainless" to "blue", and they came back! Whodathunkit?

If I log in at a different computer, or use a different browser to log in on this same compuer, they come up "right". So, I must have clicked SOMETHING, but have no freakin' idea what.

My toolbar, with "my content", "my profile", etc..., along with the messenger and notification logos, has moved to the far right-hand side of the screen (see image). How do I put it back across the top? I can't drag it. I can't find any "settings", although that is what I would expect would fix it. Anybody else ever see this? It used to be like the second image...

Excellent point. And, a point well taken. I BELIEVE the filter I took out was for a 750 Luberfiner.

Yep. Very lucky! Fortunately, the engine is running great. Oil pressure holds great. Glad I caught it in time. Probably because the engine does not work very hard...or very much. The "wrong" filter was held down by the aluminum cap. But, the filter did not "seal" properly.

Exactly!!! They really should have called them "12-speeds", shouldn't they?! Mine is the RTF-915. Direct in high gear. Normal shift pattern. If you swap the gearsets in the box to make it an overdrive in high (see pic), every gear (except "direct") gets raised one notch, so the 4th and 5th positions would be reversed. If you didn't like that pattern, Fuller offers a shift plate (basically the top of the trans) which reverses the 4th and 5th shifter fork movement. This would put the pattern back to "normal". There's where all the "x-pattern" and "h-pattern" business comes from. The older boxes, incidentally, should have an "O" in the number to indicate overdrive...like RTO-915. I can't tell you a blasted thing about the newer stuff. My RTF-915 would be Roadranger, Transmission, Front-shift-tower, 950 ft-lbs torque rating, 15 speeds. Elegant system, isn't it? Just wish it was an RTFO-915, with the X-pattern body... Maybe if I ever pull it out, I'll change it!