Gary Lewis Posted August 25, 2017 Share Posted August 25, 2017 Personally I like it. I'm sure he's flipping it for a few bucks, but it's hard to find these in any condition, much less as nice as this one seems. One question though, what is "DNE electric high/low on the automatic transmission"? I don't understand that phrase. Doug Nash overdrive. Jonathan will tell us more about that particular model, but it effectively gives the C6 an overdrive. However, since the torque converter doesn't lock up, and OD is said to cause more slippage in the converter and, therefore, cause more heat. But, if you are just cruising that shouldn't be a problem. Link to comment Share on other sites More sharing options...
Ford F834 Posted August 25, 2017 Author Share Posted August 25, 2017 Personally I like it. I'm sure he's flipping it for a few bucks, but it's hard to find these in any condition, much less as nice as this one seems. One question though, what is "DNE electric high/low on the automatic transmission"? I don't understand that phrase. Like Gary said it is a high/low range auxiliary overdrive unit. Unlike the Gear Vendor's unit that engages via conical clutches, the DNE is a direct gear driven transmission that shifts using an electric motor like a two speed differential giving .80 gear reduction. If you have 4.10 gears it's like switching them to 3.28 at the push of a button. The transmission operates as usual. I can't speak to the slippage or heat factor with how it handles that gearing. About all I know of automatic transmissions is that it is the thing I will buy if I ever end up with an amputated leg, otherwise no thank you 😈 Edit: I happen to have a DNE2 that I found at the junkyard. I left the C6 tailhousing and I've got some custom flanges coming in the mail to fabricate an adapter to the back of a BW1356 transfer case. I will eventually have more info on how it works behind a ZF 5 Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 25, 2017 Share Posted August 25, 2017 Like Gary said it is a high/low range auxiliary overdrive unit. Unlike the Gear Vendor's unit that engages via conical clutches, the DNE is a direct gear driven transmission that shifts using an electric motor like a two speed differential giving .80 gear reduction. If you have 4.10 gears it's like switching them to 3.28 at the push of a button. The transmission operates as usual. I can't speak to the slippage or heat factor with how it handles that gearing. About all I know of automatic transmissions is that it is the thing I will buy if I ever end up with an amputated leg, otherwise no thank you 😈 Edit: I happen to have a DNE2 that I found at the junkyard. I left the C6 tailhousing and I've got some custom flanges coming in the mail to fabricate an adapter to the back of a BW1356 transfer case. I will eventually have more info on how it works behind a ZF 5 The issue with slippage is that torque converters w/o clutches always slip. Below their stall RPM they slip a lot, like when the vehicle is stopped at a light. But even when on the road they slip, and the closer you get down to their stall speed the more slip you have with a given load. So, let's assume you just shifted into OD while maintaining the same vehicle speed. That means you've dropped the RPM 20% and kept the same load. If you were turning 2500 RPM you are now turning 2000 RPM. The stall speed on a Ford C6 is said to be from 1400 to 1800 typically, although it varies by application, with some going as high as 2000. So, if you drop the R's to 2000 you are now much closer to the stall speed and the slippage will increase somewhat for the same load. And, if you put a trailer behind the truck and run with the OD on you'll really be slipping - and slippage is heat. Link to comment Share on other sites More sharing options...
fljab Posted August 25, 2017 Share Posted August 25, 2017 Doug Nash overdrive. Jonathan will tell us more about that particular model, but it effectively gives the C6 an overdrive. However, since the torque converter doesn't lock up, and OD is said to cause more slippage in the converter and, therefore, cause more heat. But, if you are just cruising that shouldn't be a problem. Ah, yes of course; I know about Doug Nash overdrive units although I have no personal experience. I bet that helps that 460 get 9 mpg vs 7.5! Of course, only if you're doing less than 60. Link to comment Share on other sites More sharing options...
Ford F834 Posted August 25, 2017 Author Share Posted August 25, 2017 The issue with slippage is that torque converters w/o clutches always slip. Below their stall RPM they slip a lot, like when the vehicle is stopped at a light. But even when on the road they slip, and the closer you get down to their stall speed the more slip you have with a given load. So, let's assume you just shifted into OD while maintaining the same vehicle speed. That means you've dropped the RPM 20% and kept the same load. If you were turning 2500 RPM you are now turning 2000 RPM. The stall speed on a Ford C6 is said to be from 1400 to 1800 typically, although it varies by application, with some going as high as 2000. So, if you drop the R's to 2000 you are now much closer to the stall speed and the slippage will increase somewhat for the same load. And, if you put a trailer behind the truck and run with the OD on you'll really be slipping - and slippage is heat. Thanks Gary, that is a good explanation. No wonder the C6 is such a lousy combination with the 6.9 diesel. The engine's torque peak is 1,400 rpm which is at or below the stall speed. No bueno. The I6 is in the same boat. When the rpm's are in their happy place the torque converter is starting to slip. Just. Wonderful 🙄 Link to comment Share on other sites More sharing options...
Recommended Posts