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View Full Version : Best Tranny for Diesel Setup

jMedia
11-05-2009, 04:48 PM
Hey all, I've been further and further researching my diesel swap plans, and stumbled upon the recently revived thread on the nv3550. In it, someone said that the nv4500 paired with tall gears was not that great for a DD.

I had been looking exclusively for the nv4500 but with my 3.31 gears and plans to never really offroad, should I be looking elsewhere?

Thanks everyone
-Josh
gotmike
11-05-2009, 05:03 PM
the dodge w/ the nv4500 came with 3.54 gears... that's not that far off... if you are running hiway alot you can go with an NV5600 too... that's the 6 speed...
jMedia
11-05-2009, 05:39 PM
the dodge w/ the nv4500 came with 3.54 gears... that's not that far off... if you are running hiway alot you can go with an NV5600 too... that's the 6 speed...

That would be really nice but those seem very hard to find and very expensive.
And, I'm not that familiar with transmission lingo, but the granny gear on the nv4500 is said to be real low, is that gonna be a nuisance for city driving?
gotmike
11-05-2009, 05:47 PM
a granny gear is just that... a gear you use only when you want to go ultra slow... I.E. towing, offroad, or anything that requires super slow speed... i rarely ever start in anything other than second gear on the street...
Mikel
11-05-2009, 05:52 PM
That would be really nice but those seem very hard to find and very expensive.
And, I'm not that familiar with transmission lingo, but the granny gear on the nv4500 is said to be real low, is that gonna be a nuisance for city driving?

I very rarely use 1st gear and I have 3.08's. I will even start in 2nd when facing uphill unless the truck is loaded.
J10Mike
11-05-2009, 06:21 PM
Right...I rarely use first gear. I do have the NV5600.
jMedia
11-05-2009, 07:10 PM
How about the ax-15? I know it isn't any where near as strong but it's geared a bit better for a DD. Think it could handle a 6.5L?

Not I've never offroaded and have nothing to tow :D
gotmike
11-05-2009, 08:02 PM
you would be better off with a ford ZF6 (i think that's the name) or any number of other chevy manual tranny's...
jMedia
11-05-2009, 08:55 PM
you would be better off with a ford ZF6 (i think that's the name) or any number of other chevy manual tranny's...

guess I should be asking elsewhere then, unless someone knows of one? I just thought if I stuck with the ax-15 it'd be easier to mount up to the gw frame
jMedia
11-06-2009, 04:14 AM
Just would like to know if the ax15 would work cause there is a good deal for the AX-15 in my area right now
Cecil14
11-06-2009, 10:07 AM
The AX-15 will not stand behind a diesel. I think even the NV3550 might be a stretch. How much power are we talking? I'm guessing my stroker is somewhere around 300 lb ft of torque...maybe a little more. So far the NV3550 has done very well...haven't had it all that long though so I can't really speak for longevity.


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Daddio
11-06-2009, 09:11 PM
I would say a turbo400 with a gear vendors overdrive. I had a 3/4 ton 4x4 6.2 suburban at one time and it was screaming to do 70 mph. Even 65 mph seemed too much at times. I think it had 3.73 gears, but I don't remember for sure. It seriously needed an overdrive. The TH400 is great, but it needed a highway gear for a 6.2. The newer option is a 4L80e which is based on a TH400.
Old Iron Eccentric
11-07-2009, 08:02 AM
That 6.5L would kill an AX15, especialy in a vehicle this heavy and having to move 3.31 gears...
Mikel
11-07-2009, 08:17 AM
I would say a turbo400 with a gear vendors overdrive. I had a 3/4 ton 4x4 6.2 suburban at one time and it was screaming to do 70 mph. Even 65 mph seemed too much at times. I think it had 3.73 gears, but I don't remember for sure. It seriously needed an overdrive. The TH400 is great, but it needed a highway gear for a 6.2. The newer option is a 4L80e which is based on a TH400.

Based on my experience, with a diesel you want lots of gears you can shift sequentially. Having a separate overdrive is nice, but you still have a big jump between gears in the TH400. With engines that have a narrow power band, it can be very annoying.
Daddio
11-07-2009, 08:46 AM
The th400 shift points are easily adjustable with a switch on the top of the injection pump. I had mine set to shift fairly early and the only time you noticed a lack of gears was above 65mph. The power band is fairly wide on a 6.2 and the max power is at 3600rpms. A lot of that is actually determined by the injection pump.

Whatever transmission you choose, I don't think strength is a big issue with a 6.2na since max hp for the J engine was 142 and torque was 260ftlbs. They could get great mpg though.