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Borg Warner 4401 tcase info?

Mattygwheeler

Mattygwheeler

Well-known member
Joined
May 21, 2020
Member Number
1036
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213
hey everyone! I’m gathering parts to one ton, solid axle swap, 4wd swap my 2005 GMC 2500 with 6.0 and 4l80e. I have this BW4401 PTO tcase and 4l80 adapter from a mid 90s k3500. There isn’t much info on the 4401 tcase specifically regarding the coil, clutch shift mechanism. I Was wondering how it works? I can shift the case through all its modes using the manual shifter, the diagrams I have found are not very clear. Parts 24 and 22 in the diagram is the coil, shifter device. There is a 1 wire plug leading to the coil mechanism, this coil must shift something but everything works manually? Maybe shifts the PTO? Anyways, seems kinda newbie’ish so I posted here.
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I have a BW4401 in my 53, looks just like yours except a slip yoke rear. As I'm slow at projects, it hasn't driven yet. I did find this diagram when I found the one wire at the rear output.

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I'm not sure if it's more to help synchronize the front axle shifting or for internal to the transfer case. I have no wired the synchronizer coil yet. When shifting it into 2H, N, 4H, and 4L all the driveshafts do what are expected with no load (turned by hand), so I'm interested in the real answer.

Edit: My intent is to wire up ignition power or ground through the transfer case position switch in the front of the case to a relay for the synchronizer. Easier than a switch on the dash to remember to turn on and off.
 
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I have to knowledge about this t case but diagram makes it look like the "1 wire" is to engage the pto gear to the input shaft
 
Unfortunately this is one of the tcase ive never touched and know nothing about (other than fuck bw designs in general)

But i did find this bit of info. Guy wired in the coil and gained 2wd lo.

1/2T NP241 to 1T BW4401

I just swapped a BW4401 in my 1/2 ton along with the NV4500 (all from a 1T donor truck of the same year). All the plugs fit together perfect, although one connector had 3 wires in my truck, and only 2 pins on the tcase. There is also one wire connector on the tcase unplugged because I have...
www.gmt400.com www.gmt400.com
 
total newb said:
Unfortunately this is one of the tcase ive never touched and know nothing about (other than fuck bw designs in general)

But i did find this bit of info. Guy wired in the coil and gained 2wd lo.

1/2T NP241 to 1T BW4401

I just swapped a BW4401 in my 1/2 ton along with the NV4500 (all from a 1T donor truck of the same year). All the plugs fit together perfect, although one connector had 3 wires in my truck, and only 2 pins on the tcase. There is also one wire connector on the tcase unplugged because I have...
www.gmt400.com www.gmt400.com
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I guess the 4401 is very similar to the 1370, but yah a strange design. 2LO sounds like it would be handy, but do I take the risk putting work into the BW case just for it to be a giant turd, or should I just source a 241? I originally wanted to run a divorced np205 but I had the 4401 already squirrelled awy and want a bit more low range…
 
My only experience with them was learning that the front output was clutch driven not gear driven, that information immediately put it on my scrap list.
 
Thatg9659 said:
My only experience with them was learning that the front output was clutch driven not gear driven, that information immediately put it on my scrap list.
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If it's still more than strong enough to break shit downstream who cares?
 
my f150 has the BW4406 case. recently swapped to the manual shift version. did not wire in the coil, no issues yet... my understanding is that it synchronizes the front output when you shift to 4wd. pretty sure its a 1-2 second deal then off.
 
I don't think it's a turd case. Front is still mechanically connected via a collar (parts 22a & 22c). Weird clutch that moves them, but all power still goes through spline drives.

I also haven't heard of these year 3500s destroying cases. Anecdotal, but if they were junk I think there'd be more info on how to swap them out of the trucks they came in. Especially with how dump bodies and plow trucks get overloaded and driven without care.

Thicker chain than a 241, and already on hand. That's why I used one, mine was attached to the NV4500 I wanted. I could see swapping to an NP205 or gear driven case, but not to another chain driven one. I do wish mine was fixed output due to a really short rear driveshaft.
 
Projectjunkie said:
Very cool


Reading between the lines here, this is a 2wd? Going to cut down the 4l80e output in the truck?
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Yah that’s right. 2wd, 6.0 4l80, I got the truck dirt cheap just to do dump runs, deal with yard waste, etc. Once I cleaned it up turns out to be a half decent rig worth keeping around but it needs to be 4x4. Gonna cut the tail shaft down like buddy did in this video.
 
I ran a BW4401 fixed rear yoke in my 1999 K3500 on 40's and SAS for 7 or 8 years and never had a single issue with the T case. I left the wire in question disconnected the entire time with no ill effects. T case worked perfectly in all positions.
 
What about mating the borg case to a np203 doubler? The 203/gm 6 bolt pattern kit with 32 spline output should allow all this to work together. Will the Borg hold up? Or should I keep looking for a Ford np205?

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Mattygwheeler said:
What about mating the borg case to a np203 doubler? The 203/gm 6 bolt pattern kit with 32 spline output should allow all this to work together. Will the Borg hold up? Or should I keep looking for a Ford np205?
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Will probably be fine as long as you don't get too stupid with high horsepower and high traction.

I'm planning on doing exactly that with a 271 in the near future. I figure if the diesel puller guys only occasionally pop them then it should survive a sub 300hp engine just fine even with a 2:1 reduction in front.
 
Yah the borg came from a k3500 with a 454, should handle some torque. It’s going behind a 6.0/4l80. The truck is mainly being built to haul firewood out of the bush and have some fun on the side.
 
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