Manual shift transfer case

PLanB419

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2002 Super duty, 7.3, 321k on the odometer, auto transmission, electric shift transfer case.

Lately I've been hearing a grinding noise at low speeds coming from the transfer case, I drained it and found a piece of what looks like a planetary thrust washer.

I found locally a guy with a manual shift transfer case for 300 bucks. A rebuild kit for the electric is about 200 plus down time, so going with the manual shift is the way to go.

I know the case needs to be for an automatic transmission, that I need the shifter boots, going to get the truck side of the electric plug. It should just be a plate to pull on my floor. Is there anything else I should also grab? Anything I should replace while I've got it apart? Thanks in advance.
 

DaveBen

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I would go for it. I have NEVER had an electric xfer case. The can go bad out on the dirt road.
 

79jasper

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Otoh, my experience with bw1356's has been sheet. I don't know what model the sd's use for manual.

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PLanB419

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So I bought the case it went in smooth, the only issue I ran into was the shift linkage. There are a couple options on the linkage the one I got set the shifter back too far, I will get the other setup today.

Does anyone know how to adapt the wiring harness so that the shift light will come on?
 

madpogue

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Shift light? There are 4X4 and LOW RANGE lights. They're triggered by a switch on the case that's separate from the manual or electric shifter. Should be the same switch, two-wire connector. Oh, this is going from knowledge of the OBSes; SDs are probably different.

The different linkages are based on whether the t-case is behind an automatic or a manual transmission. Automatics are longer, and so the t-case is set further back, requiring a longer bar between the lever on the t-case and the shifter. It's just flat stock with two holes in it, and bushings; a lot of fellas just fabricate something.
 

PLanB419

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It's a little different between the obs and super dutys. The manual shift t-case has a two prong plug that grounds the switch for either 4 high or low. The electric has two sets of plugs, total of 8 wires, non of which match the manual. I will probably just run new wires to the dash or leave it alone.

As far as shift linkage goes the automatic linkage is about 4 inches longer than the manual. I pulled everything from a truck with an automatic transmission, which should've been a straight across swap. However for some reason the adapter plate on the automatic sets the shifter back too far(on my truck). The plate for the standard transmission sets the linkage 1 5/8 forward. Not sure why, but that will set the shifter into proper location. I may still have to lengthen the shifter rod.
 

PLanB419

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Top picture is the linkage on a manual transmission, manual transfer case. The bottom is mine, this is all the way forward in 2 high. You can see where I had to massage the opening to allow 4 lo.
 

rwk

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Should be a NP 271, we just changed ours out in a 99 SD, but it was manual shift, see my post 4R100 trans problem, our linkage/shift lever came off, small pin on pivot broke off, allowed lever to slide off,caused shift fork to wear out, was low on fluid also, all else looked ok, bearing, chain, planetary, ect, make sure linkage is in right!
 

PLanB419

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The smaller bracket is for a manual t-case on an automatic transmission, the other is for a manual transmission. The only difference is the the location that the shifter linkage bolts to the transmission. On the small bracket (auto tranny) the shifter pivot sets in the back of the two holes, bolts in the forward hole. On the larger bracket (manual tranny) it sets the shifter in the center hole and mounts using the back hole, This sets the shifter forward 1.7 inches.

My truck came with an auto tranny and auto t-case. The manual case I bought came off of an auto tranny and I pulled all the linkage that came with it. I matched everything up, counted splines( both 31). Everything went together like butter, until I went to connect the shifter linkage. For some reason the automatic transfer case plate did not put things into the correct spot. I ended up using the plate from the manual transmission, which moved the linkage forward 1.7 inches. Once I did that everything lined up perfect. I did however lengthen the actual shift linkage arm by the same 1.7 inches. Everything works as it should, boot fit on like it was factory.

I stiff have yet to figure out how to engage the shift lights, as they are entirely different plugs.
 

rwk

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our manual just has a 2 wire plug, think the NP 273 auto case shift light works thru the motor plug?
We wanted to use the auto case they cost less around here, paid 150 for u pull manual one, buts that what we had original.
 

PLanB419

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150 for a case would've been nice, paid 300 was the same for either one.

The manual case does just use a two wire plug, it grounds out and turns the lightS on. The auto case uses two plugs one with 6 wires the other with two. It is controlled by the GEM and a pair of relays under the hood. However I believe the lights themselves work in the same manner. I would just have to physically run two wires from the case to the dash, bypassing the GEM.
 

madpogue

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Couldn't you just figure out which two wires on the auto case connector(s) are for the lights, and splice a manual switch connector to those two wires? You'd have to figure out which is for the 4X4 light and which is for the LOW RANGE light, but you could do that by experimentation.
 

PLanB419

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You would think so, however the wires for the auto shift tranny run to the GEM module or to a pair of relays under the hood. The indicator lights are tied into this systm on the auto shift.

The manual shift case simply runs directly to the indicator lights, grounding out to complete the circuit.

I will likely just do this as well, it would just require me running two new wires from the case to the back of the gauge panel
 
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