Need Highway Gears for a 14B

[HotRodYJ]

I know a bunch of you guys running 14B (10.5") rear axles have the old stock 3.73 gears laying around someplace. What do you have and what do you want for them?

I've got me a new toy, a 94 Chevy 4 dr long bed dually, 2WD with a 6.5 turbo diesel. I've not cracked it open yet but I'm pretty sure it's got 4.10 gears in it, although it could have 4.56. Anyway since I'll never be pulling much over 5000 lbs, a better fuel mielage gear is what I'm after to lower the rpm and get a couple extra mpg's. I'm sure one of you has a 3.73 gear set laying around in your way. Anybody got anything other than that?

Thanks for the help

[pplblazerdude]

I could be wrong but most of the chevy diesels came with 3.73.

[HotRodYJ]

3.73 is standard with 4.10 and 4.56 both option's. Someone opted for the deeper gears in this truck. I confirmed it does have 4.10's in it with the factory locker (Gov-Lock). This as shown on the original window sticker.

[Pitch]

Steve's got some.

[pplblazerdude]

3.73 is standard with 4.10 and 4.56 both option's. Someone opted for the deeper gears in this truck. I confirmed it does have 4.10's in it with the factory locker (Gov-Lock). This as shown on the original window sticker. ahh got you. I thought by the way i read the post you where just guessing my mistake.

[HotRodYJ]

I've decided to hold out and just order a new set of 3.42's for it. I ran the truck today at 70mph and it was turning 2800 rpm. That's way too high for a diesel, they say the sweet spot for the 6.5 is 1800 rpm, others say 2200rpm. Either way 2800 I'm seeing is WAY to high so I got plenty of room to cut that down and still be able to tow 7000 lbs or less with no trouble.

[BillM]

You should be able to get about 10K still pretty easy.

[HotRodYJ]

I did read one pocssability today that may explain my VERY high rpm numbers I'm seeing. The tach actually take's it's readings from the Alternator since a diesel doesn't have a distributor to take off from. My truck is supposed to have a 62 mm pulley on the alternator. The later trucks from about 96 on up had 57 mm pulleys. If by chance mine has the wrong size pulley the tach will read higher than actual rpm's. I'll check it tonight, but this may answer part of the high rpm question. Either way, it still needs new gears to up the mpg and lower the rev's to something reasonable. It does have a fairly new NAPA alternator on it so this is entirely possible. I'll keep you posted on what I find.

[Gubni]

Numerically lower gears would strain the engine on a heavy pull. Typically the bigger the load ratiing the numerically higher the gears. Do you have stock size tires?

[1-tonmudder]

If at all possible I'd leave the gears in it.A 6.5 needs all it can get.

[bcowanwheels]

i,am puttin 2.73 gears in my 14b with a 6bt cummins. i want a good 75-80 mph low rpm cruise

[HotRodYJ]

Sure enough, I got too small of a pulley on the alternator. I'll swap it out and see what the motor is really doing. I know all about the pros and cons of the gear swap, this baby sings way to fast at highway speeds and needs some help. It should still do all I need it too with a higher (lower numeric) gear ratio. 90% of the time it's just a daily driver with nothing behind it. If I plained on driving 50-55 mph everywhere I went it would be fine like it is. I typically tow at 60mph anyway, but unloaded I'd rather run 70 -75 mph. It wont do that comfortably like it is. The 6.5 is not even compariable to a Cummins or Powerstroke and I don't expect it to tow like it had 600HP and gob's of torque. Most of the towing I would do with it would be a 5000 lb camper at 60-65 mph. My last truck had 3.08 gears in it with a 400 small block that never had the power it should have had, and it still always did what I needed it too. It didn't always like it, but it got the job done.