[firebird_1252]

when are gears just too low? or are they not? use for example a ex walmart truck.. eather 2.93's or 2.64.. pulling weight.. is that too low ?

[classictruckman]

on level ground you might be ok, but the rest of the drive train better be top notch, I've seen a couple of driveshafts peeled like oranges because the ratuo was to low to come out of a hole, then again I do a lot of off road work.

[firebird_1252]

i never go off road. hopefully wont.. and ALWAYS use low gear... even bobtailing

[terrylamar]

This is a Direct Drive Transmission, a 1:1 ratio. This is one of the best combinations out on the road. Depending on how fast you want to drive either ratio is fine. Use the 2.64 to drive faster, above 60 mph and the 2.93 below 60 mph. These ratios are capable of great fuel mileage.

The 2.64 is comprable to a 3:55 with a double overdrive.

[firebird_1252]

Originally Posted by terrylamar

This is a Direct Drive Transmission, a 1:1 ratio. This is one of the best combinations out on the road. Depending on how fast you want to drive either ratio is fine. Use the 2.64 to drive faster, above 60 mph and the 2.93 below 60 mph. These ratios are capable of great fuel mileage.

The 2.64 is comprable to a 3:55 with a double overdrive.

i'm sorry but a bit confused. so 2.64's above 60 would be good. 2.93 below?

these trucks have 10speeds in them.

i'm looking at single turbo c15's or isx's.

i thought this would be a good topic.

[terrylamar]

Originally Posted by firebird_1252

i'm sorry but a bit confused. so 2.64's above 60 would be good. 2.93 below?

these trucks have 10speeds in them.

i'm looking at single turbo c15's or isx's.

i thought this would be a good topic.

The lower the gear ratio the faster you can go and be in your sweet spot.

Yes, they are 10 speed direct drives. Check to be sure, but I'm almost positive.

You can operate a Cat engine at lower rpms and it will pull well. I have 3:55 rears, a double overdrive, with a final of .73. At 57 I am turning 1225 rpm. For most engines this is a little low, but my Cat will pull down to arround 1000 rpm. Just because it will doesn't mean I do regularly. My sweet spot is about 1350-1375, but my range is pretty broad, 1000 to 1500 rpms.

Can I assume this Cat is 2003 or earlier, a pre ACERT with a serial number of 6ZN? If so this is probably the best Cat out there. It will get the best fuel mileage of all Cats and being pre ACERT, relatively, maintenance free.

[firebird_1252]

i need to stop posting half awake/sleep.

what i ment was.. isnt the ratio too low where you'd be lugging?


as far as that cat goes... its not a 6nz.. its a single turbo 04

[terrylamar]

Originally Posted by firebird_1252

i need to stop posting half awake/sleep.

what i ment was.. isnt the ratio too low where you'd be lugging?


as far as that cat goes... its not a 6nz.. its a single turbo 04

No, if your transmission is a Direct Drive 1:1 with 2.64's, it is roughly the equivalent to a 13 sp with 3:55's. It is as near perfect as you can get. Your transmisson is working most effeciently at a 1:1 ration rather than a final ratio of an overdrive.

What does the serial number start with? It may be a bridge motor, half ACERT and half not. You do not want a bridge engine.