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D400 - Should I convert from Manual to Auto? #2539529
08/21/18 12:29 PM
08/21/18 12:29 PM
Joined: Feb 2006
Posts: 81
Michigan
Truck Y'all ! Offline OP
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Michigan
Hi, folks. I have a clean 1970 D400 from Oklahoma. Currently has a /6 NP435. I have a nice 440...all done, from a different project.

I've already ditched the 6.6:1 rear axle in favor of a Dana 70HD. Retained the nice 20" wheels.

Since I need to use this truck for hauling and moving stuff around (highway driving long distances), I thought the 440 would be a better way to go.

Finding all the pieces to retain an NP435 (hydraulic clutch) behind the 440 is pretty close to building a decent 727.

Any thoughts, opinions on this move?

Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2539792
08/21/18 10:39 PM
08/21/18 10:39 PM
Joined: Jan 2003
Posts: 10,486
Freeport IL USA
poorboy Offline
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A D400 is a pretty big truck that can carry a big load. If you intend to load it up, it might get pretty rough on the 727. Most modern big trucks with an auto trans has an Allison, and they are a lot more heavy duty then a 727.
The NP435 has a low 1st gear to get things moving from a dead stop.

My concern with the 727 would be about the life expectancy. Be sure its build for pulling a heavy truck with a heavy load, unless you don't intend to load the truck very heavily. Gene

Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2539890
08/22/18 02:37 AM
08/22/18 02:37 AM
Joined: Sep 2003
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east side of Ohio
basketcase Offline
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basketcase  Offline
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lets see that beastie


Dave


1981 Dodge D150 360 auto
Re: D400 - Should I convert from Manual to Auto? [Re: basketcase] #2540196
08/22/18 09:45 PM
08/22/18 09:45 PM
Joined: Jan 2007
Posts: 7,664
IN
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ahy Offline
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I think the 727 would work if built properly and big trans cooler and right rear ratio. I think the NP435 would work better however. The NP435 is rated for low 20k lb gross weight from memory... a good medium duty truck transmission. The low 1'st is great for slow running on rough ground or to get her rolling when heavy.

Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2540254
08/23/18 12:29 AM
08/23/18 12:29 AM
Joined: Sep 2011
Posts: 2,042
colorado
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savoy64 Offline
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savoy64  Offline
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colorado
i always heard an automatic can start a bigger load on a hill than a manual-----from what you guys are saying maybe they meant starting downhill---and dont forget the 727 stood up to the cummins and the OD variants after that are based on the venerable 727.....

Re: D400 - Should I convert from Manual to Auto? [Re: savoy64] #2540260
08/23/18 12:37 AM
08/23/18 12:37 AM
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Posts: 954
garnett kansas
rhad Offline
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garnett kansas
i have a 727 out of a motor home with a 440,it needs a rebuild ,ive always been told they were the heavy duty units?,its a short tail shaft unit


my ladder of success is missing some rungs
Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2540431
08/23/18 01:45 PM
08/23/18 01:45 PM
Joined: Jul 2007
Posts: 4,889
Wills Point, Texas
Hugh Jorgan Offline
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Check prices on a wrecker to tow you home when the 727 craps out...and it will.

jmho.



Wouldn't a 12 valve & NV4500 be a better fit?

Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2540623
08/23/18 09:54 PM
08/23/18 09:54 PM
Joined: Dec 2009
Posts: 283
STL ,MO
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Handygun Offline
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STL ,MO
435 over 727 in that app. I know where a BB hydrabell is if your looking.

Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2540831
08/24/18 12:00 PM
08/24/18 12:00 PM
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colorado
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savoy64 Offline
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colorado
boy i cant believe all the nervous nellies here talking crap about automatics------makes you wonder how stupid the guys are that are racing with automatics in all classes of truck racing---strip--off road--pulling contests-----a friend, butch brooks, builds performance automatics and has about 30 teams that run his trannys-----a few years ago in the world championship rock crawling event in moab utah his trannys placed 1-2-3-5 with 4th place going to a nv4500-----the only real advantage of the manual is holding the unit back going down a colorado mountain pass----yep i do have an nv4500 in my cummins truck and a getrag in my 71 govt truck but still not scared of an automatic in a truck application.....

Re: D400 - Should I convert from Manual to Auto? [Re: savoy64] #2540863
08/24/18 01:31 PM
08/24/18 01:31 PM
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Chilliwack B.C. Canada
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RUNCHARGER Offline
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That 440 won't put out any more power in your D400 than it will in a 10 seccond race car. The motorhome trans usually have good internals if you can find one. ALso use a big trans cooler.


Sheldon
Re: D400 - Should I convert from Manual to Auto? [Re: savoy64] #2540879
08/24/18 02:07 PM
08/24/18 02:07 PM
Joined: Dec 2009
Posts: 20,600
in a cattle trailer down by th...
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Guitar Jones Offline
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Originally Posted By savoy64
boy i cant believe all the nervous nellies here talking crap about automatics------makes you wonder how stupid the guys are that are racing with automatics in all classes of truck racing---strip--off road--pulling contests-----a friend, butch brooks, builds performance automatics and has about 30 teams that run his trannys-----a few years ago in the world championship rock crawling event in moab utah his trannys placed 1-2-3-5 with 4th place going to a nv4500-----the only real advantage of the manual is holding the unit back going down a colorado mountain pass----yep i do have an nv4500 in my cummins truck and a getrag in my 71 govt truck but still not scared of an automatic in a truck application.....


I have to agree, if a 4WD 2000 horsepower diesel truck can use a torqueflight to run high 7's there is no reason to be worried.


"Follow me the wise man said, but he walked behind"


'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost coming soon!
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2541301
08/25/18 05:05 PM
08/25/18 05:05 PM
Joined: Dec 2006
Posts: 2,094
Byron, NY
W.I.N. Racing Offline
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Byron, NY
A 727 can take the abuse... if you want an auto go for it


'01 P1500, Blown/Inj BAE,/Veney ,Bruno/CS2,Dana 60
'01 Dodge 3500 S Cummins Auto, Fresh air kit, 4" Exhaust,
'05 Dodge Magnum R/T - Too Much to list
'60 Willys CJ5
'01 International LPX - Project,DT466, Allison
'64 Plymouth Valiant, Inj 528 Hemi, 2spd
Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2543477
08/30/18 03:24 PM
08/30/18 03:24 PM
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo Offline
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I would keep the stick. I hate towing with automatics. Unwanted downshifts, no downshifts when you want them and always worrying about when it's going to puke. No thanks.

Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2543639
08/30/18 11:50 PM
08/30/18 11:50 PM
Joined: Jan 2003
Posts: 10,486
Freeport IL USA
poorboy Offline
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I have no doubt that a 727 can be built to do the job, but at what cost?

There is a pretty signigifent different difference between a high power motor abusing a trans for 7-12 seconds, or rock crawling at very slow speeds and a 6 mile 6% uphill grade pulling 20,000 lbs.
Ask Rhinodart how those 727s and their derivatives hold up dragging heavy loads across the country. Gene

Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2543733
08/31/18 07:35 AM
08/31/18 07:35 AM
Joined: Dec 2009
Posts: 20,600
in a cattle trailer down by th...
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Guitar Jones Offline
Paddle faster! I hear banjo music!
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in a cattle trailer down by th...
Rhino dart is not a good example. If he had an anvil for a trans he could tear it up.


"Follow me the wise man said, but he walked behind"


'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost coming soon!
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
Re: D400 - Should I convert from Manual to Auto? [Re: basketcase] #2559344
10/05/18 12:12 PM
10/05/18 12:12 PM
Joined: Feb 2006
Posts: 81
Michigan
Truck Y'all ! Offline OP
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Truck Y'all !  Offline OP
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Michigan
Here's my girl. By now, the /6 is running well... and I need to start moving stuff so... It's gonna be a 6 cylinder truck for a little bit until I can get the trans question(s) sorted out

38085040_10212786065949732_7698695630738161664_n.jpg
Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2559450
10/05/18 02:54 PM
10/05/18 02:54 PM
Joined: Sep 2003
Posts: 7,828
east side of Ohio
basketcase Offline
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love it! Hard to imagine a truck that size having a Slant.


Dave


1981 Dodge D150 360 auto
Re: D400 - Should I convert from Manual to Auto? [Re: basketcase] #2559585
10/05/18 06:48 PM
10/05/18 06:48 PM
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Posts: 3,535
Canuckville
68Cbarge Offline
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Originally Posted By basketcase
love it! Hard to imagine a truck that size having a Slant.


It is all in the gearing and torque multiplication..
What do you think all truck companies engineered back in the 30's,40's and early 50'S before offering OHV V8's??
The slant six is more efficient than its flathead it replaced and has a stronger bottom end.

It may not have much horsepower but makes enough torque to do the job.
People say that today about some diesel engines.

The 440 upgrade is a great idea with the right cam to suit the heavy truck application.
727's survived underneath giant Travco RV's yet I would stick with the stick if it were my truck.
Cheers


'68 Newport Custom Barge on a Budget!! BOAB
1973 Satellite WAGON! 318- 3 on the tree!!
2008 Chrysler 300c HEMI!
Re: D400 - Should I convert from Manual to Auto? [Re: Truck Y'all !] #2559808
10/06/18 11:48 AM
10/06/18 11:48 AM
Joined: Mar 2017
Posts: 195
Coastal Maine
Mr onetwo Offline
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Coastal Maine
Sell that 440 and put a Cummins in that beast!

Re: D400 - Should I convert from Manual to Auto? [Re: Mr onetwo] #2559837
10/06/18 12:42 PM
10/06/18 12:42 PM
Joined: Jan 2006
Posts: 3,535
Canuckville
68Cbarge Offline
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68Cbarge  Offline
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Canuckville
Originally Posted By Mr onetwo
Sell that 440 and put a Cummins in that beast!

iagree
Much better idea!


'68 Newport Custom Barge on a Budget!! BOAB
1973 Satellite WAGON! 318- 3 on the tree!!
2008 Chrysler 300c HEMI!
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