2.62 gear ratio

I would like to add that my son owns a 2000 pete with a 1MM 600 hp Cat, 18 speed, with 3.36 eatons and 11R24.5 tires. This truck is stout, I put much love in it. Money was no object even though he didn't ask me too and he insisted on buying all parts. I just didn't tell him every thing bought. The pride of building an engine for your son well you get the idea. Pulls a grain wagon with it he is at gross or over gross all the time 80000 lbs. Most his driving is flat on that side of the river. He uses low to get it rolling or started, once it moves even a foot its cool. Now he isn't using a b ratio set so it doesn't have the lower low gears but my point is if 3.36 is touchy to get rolling then what would 2.62 or 2.93 be like. Also as far as the pinion with 14 teeth being stronger that's an illusion, the teeth are also cut deeper into it. So they are longer what will this matter right well the longer the tooth the easier it shears under pressure.

 

They are equivalent. Direct is direct. I could have gone with a 10 direct with the 2.64 rears I have, but I have an 18 spd. I run it in direct (16th) all the time at road speed. But unlike the 10, I have 16 gears to play with for just about any situation I run in to. I did this in a glider, and I could have gotten a 13 I suppose, or even a 10 direct, but the 18 rebuilt was the same price as a 13 rebuilt, and the 10 would not come in a torque rating high enough for what I needed. So, the 18 got selected.

 

Ok......you get the last word....I'm cryin "uncle"

 

I wasn't in a place to read and type that fast earlier today is all. It doesn't matter to me how your truck is set up if you like that is what matters. If you have had CATS till now that's gonna be your biggest issue cause what you have now will never be one. There again its that give to get deal I mean if you want a new truck what else are you gonna get right.

What did stir me was one party involved in the discussion wanted to talk down to me called me silly. He don't have sense to know what an overdrive is. He was totally shocked that the driveline turns faster out of an overdrive. Well if the rear is a constant, the engine is constant where in the hell did he think the speed with low eng rpm comes from. As far as you and allan05 yall made respectful valid arguments. As stated earlier it don't make a hill of b eans but we did make a day of it, and it beat nothing to do did it not?

They call me "wore out" we gone yall have a good ride

 

Thanks Cowpie1, would have thought the extra rotating mass would have some loss, although not noticeable. One poster said a 10 direct with 2.62 or whatever would pull a hill as good or better than an 13 or 18 with 3.55 in a gear that makes overall ratio the same. Most of us run 3.90 or 3.70, Irun 3.55 not much difference after you get out on the clutch. A few have tried it with 3.36, not only can't they get out on the clutch but the can't come close to us on the hill's. like I said before we don't get fuel mileage anyway and best I can tell they have no noticeable gain or loss. and on the way back the 3.36's will not pullout as high as the 3.70 or 3.55 except on a long down hill. Cowpie this is not direct at you, I know you are all about fuel milage and what you have works, just don't won't someone to think he's going to get 8 miles to the gal and pull a hill with the Large car's

 

Wore out I gotta give you props....I thought for sure you had been dragged down and beaten' with experience.

But you dug in and climbed back out.

Good game outta you!!!!

 

Experience?!? Now that's funny.

 

Just want to extend this conversation. 3.58 ratio is actually 3.58:1. 3.58 spins of the driveshaft/pinion for every 1 spin of the gear/axle. Not 3:58 or 2:64. I see Bruce from Pittsburgh Power publish those kind of numbers and they're incorrect.

a ha! The truck was geared incorrectly to begin with. It should've been a lower gear (higher numerical). That would improve startability, fuel mileage, and ability to hold gears, all three things you mentioned. That's why you can't just slap in any ole gear, you have to look at each gear in the transmission with the rear gearset as a total system. So to compare a regular overdrive setup to one that is direct drive but incorrectly geared is not the correct way to go about things. Even comparing a C ratio overdrive 10 speed to a direct isn't fair. Like I said 2.62 gears with a direct 10 speed vs 3.58 with a B ratio 10 speed match up all less than 1% in all 10 gears. It feels exactly the same to the driver.

Higher gears (lower numerical) have less losses through the differential for the same road speed. Add in a transmission that is spinning 1:1 thereby no torque is going through the countershafts, and you have the most efficient setup possible.

When we get into direct drive setups, there's a lot more things to worry about that's why you don't see many setups like that. Generally you're limited to torque, maximum road speed, startability, gross weight, and transmission choice. More than a few makers have little experience with direct drive setups, like the one poster talking about Peterbilt. You have to remember the OEMs don't want to stray far from their formulated setups, warranty being the main concern. Sometimes you have to be insistent and escalate the issue. OEMs all have the ability to bypass their formulas with approval from an engineer.

Volvo has an interesting setup, the XE13 drivetrain. Volvo I-shift OD transmission with 2.64 gears. You read that right. You cruise at 1150 rpms at 65 mph, and have a starting gear of 31:1 overall.

 

Really? You are so close but so far. Go do more research write it all down then retake test you may pass lol

 

Are you talking to me? If so, you're the one that needs to re-take the test. Nice try.