Rear Axle Gears

[Bad93Cummins]

I swapped in a NV4500 from my A518 auto tranny. I notice that in 5th that 70-75 is pretty high rpm, should I keep my 3:54(I belive that's whats in my truck) or should I go down to 3:07 like how the 5 speeds come from the factory?

Its 2wd truck.

[oldestof11]

rbrettctd put a G360 in his truck that had a 727 and a 3.07 and he loves it! 23mpg and keeping up with the Dmax's.

[Richie O]

3.54's and a overdrive should not be to high of an rpm at 70. I have 4.10's in my rag truck and I can do 90 plus in high gear. I would stay away from 3.07's due to the lack of parts. They don't make the ring and pinion any more so they can be a pain to find a good used set. As far as I know 3.07's never came in a standard equipped truck, only the auto's from 89 to 91.4 ( and Philips 93 )

[oldestof11]

Richie, available all the way to 93 in the FSM is the 3.07 gear set by special order only. At least this is what I was told.

[Richie O]

Richie, available all the way to 93 in the FSM is the 3.07 gear set by special order only. At least this is what I was told.

Like I said, the only one I have ever heard of is Philips 93. I have yet to see another 91.5 up truck with 07's.

[PToombs]

You say you have high RPM's, how high? 2000 is about normal for most of our trucks at 65-70 or so.

[Bad93Cummins]

2200-2300 at roughly 70-72, was 2200-2300 at 80-82 with the auto.

[Ace]

There was a noticeable change to me in fuel consumption and driving comfort with just a couple hundred rpm's difference at cruise. A setup that's running around 1800 rpm at cruise (whatever speed that is) returns the best fuel mileage and a quieter, more comfortable ride. 2000rpms was just a little too buzzy for me in either the 1st Gen or the commonrail - same effect.

I have both my trucks set up with tire/gear combos to cruise 1800rpm at 70mph.

[Bad93Cummins]

I agree with you ACE!

[dpuckett]

Is the speedo gear from the NV4500 set up for your gears? Sounds like the "new" tranny was from a 4.10 truck. IF you didnt change the tranny speedo gear, it will still read like it has 4.10s. In other words, when it says 70, you are really doing 80. Check it with a GPS or interstate mile markers.

I almost bought a 93 D250 with a 5spd and 3.07s, til the guy sold it out from under me for $200 more than we had agreed on. Said he got it that way from the factory. I think they were available on the 3/4 ton trucks. Probably Dodge clearing out their stock before the body style change.

DP

[PToombs]

Yeah, better check the gears! You may still be doing 80-82 at 2200. Won't be good when the cop pulls you over!

[Bad93Cummins]

Everthing still the same, the spedo still reads 2mph fast. So would it be worth it to change to high gears or no?