D350 with 6bt cummins to 6L90E transmission

[Ziegelsteinfaust]

I have a line on a D350 with a Cummins I maybe able to get very cheap. The truck is out of state titled, service bed, and has a bad transmission.

Well instead of putting a stock 727 back in it. Is the 6L90 a good option?

I know the 4L80E works fine for less then 400hp depending on whom you believe.

So what say you.

[Dieselwrencher]

Does anyone make a stand a lone controller for it yet? I have very little experience with the 6L90.

[Ziegelsteinfaust]

Yes there are complete kits for both the 6L80 and 6L90, and along with tap shifters.

But diesels are their own beast, and I don't know that much.

Just I could fix the truck up, and get my money back out if I don't like it.

[slimjim66]

use a 47rh, a lot cheaper in the long run

[Ziegelsteinfaust]

All the cheap ones I found were 727TF. So if i go that way. I thought get something alot nicer

[Dieselwrencher]

You definitely don't want a 727. No lock up or overdrive. 47rh would be a lot cheaper, no adapter needed either. But it's all in what you want.

[Ziegelsteinfaust]

My new truck has a 6 speed auto, and honestly they have grown on me alot.

I don't know much about diesels, but I think it could make a tuned cummins a nicer pleasure to drive.

I only tow 8000 pounds at the most, and I wouldn't get the cummins for big hp. So I think it would live fine.

The 47RH is not a bad option, and is alot better then the 727 equipped Cummins I usually find.

[Overdriven]

Not a trans expert but from what I’ve read about the 6L80/90e they actually aren’t as stout mechanically as a 4L80e. The ability of the 6L80/90e and the newer 10spd to take big power is in the tuning. In stock form the ecm communicates with the computer in the trans constantly working together. The ecm will pull timing, lower boost, close the throttle slightly to reduce power during up shifts to reduce the mechanical load on the trans. Without electronic throttle and the increased torque of a diesel this is a something to consider. I’ve also seen a trans builder complain about the stock torque converters and recommending a billet converter for towing.

There are 1 or 2 aftermarket options for controlling these trans that I’ve seen, haven’t look recently. They are fairly new to market though. One of them I saw you tell them about your engine and they will load a base tune into their controller, doubt they have anything for a diesel. Personally I consider these to still be in the guinea pig phase regardless of engine choice and something to consider before jumping in.

[Ziegelsteinfaust]

Thanks, for your input.

I did not think of the tuning being as integral to the trans toughness vs a 4L80E. Or as said before a 47RH. Which would be easier to install, and get to where I need with it.

Probably if I get a diesel I will stick to proven formulas instead of forging my own way.

The original diesel I was looking at when I started this thread was effectively sold by the time I messaged the guy. Luckily there seems to be a few of the 89-93 Dodge D350 work trucks popping up a month. Either flat bed or service body usually $5000 or less within 200-300 miles.

I have been wanting a diesel for the last few years, and I am still debating on what I want.