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1990 Suburban, about to start 5.3/6l80E swap. Have a couple quesitons.

Discussion in 'The Engine Bay' started by Nicholas_nolte81, Feb 14, 2017.

  1. Nicholas_nolte81

    Nicholas_nolte81 Registered Member Premium Member

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    Hi everyone,

    Ive got a few questions about this swap. I have a 1990 V2500 4x4 Suburban with the NP241C Tcase and Im putting the motor and trans from a 2013 Silverado in it. I've got the driveline and had the wiring harness reworked so Im just gathering the last little pieces before I throw the engine in.

    1. Oil Pressure sensor. - I know I need to keep the 2013 sensor in for the PCM to make the engine run properly but how do I get my gauge working as well? Can I just tap into the wires and run them back to the gauges? I have the 1990 cluster so they should work together right? Can I make a T-junction and install both sensors from the same port? My truck is going to have oil cooling, could I put a sensor in line with that?

    2. Speedo - Should I just hook my 1990 VSS in the tcase into the suburbans stock wiring? Will my speedo work with just that signal? The 2013 PCM gets the data from the transmission so I dont think it also needs the one on the NP241C Tcase. If this wont work, what options do I have? I really want to have working gauges.

    3. Coolant temp sensor - I just ordered a new 2013 sensor because it plugs directly into the 1990 wiring harness. Did I waste $15? Anyone have the link to the guy who turns the old ones down so they fit into the new blocks?

    4. Trans tunnel - Anyone know if I'm gonna have to cut the trans tunnel to fit the new Trans? I had the TH400 in there stock.

    5. Radiator - Im planning on using the 2013 radiator because the truck had the HD cooling package stock and I figured I ought to keep it because I live in Phoenix. How hard is it to put the new radiator into the old truck? Im going to be using the electric fans out of the Silverado.

    6. Trans cooling - The Suburban has a trans cooler installed on it already, I could just run the lines from the 6l80E to that and avoid having to drop $125 on a stock one right?

    7. Suburban wiring - What on the suburban wiring harness can be removed? I want to make this build look as nice as possible.

    That's all I can think of for right now. Thanks for the help!

    Nick
     
  2. bigblock72

    bigblock72 1/2 ton status Premium Member GMOTM Winner

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    1. You will need to use the 1990 oil sender for the gauge to work. I would ditch the oil cooler line idea and put the sender in the block off plate on the oil pan.

    2. The VSS in the t-case will work fine. Make sure to connect the wire to the low range switch for revised low range shift points and better drivability in low range.

    3. Again you will have to reuse the coolant sending unit (1 wire) for the gauge to work. The coolant temp sensor (2 wire) is for the ECM. I like to drill and tap the water pump and put the sender there.

    4. I believe the trans will clear. I haven't personally installed one in a square body so I'm not sure.

    5. The 2013 radiator has a 34 inch core, the 1990 is a 28ish inch core. I think the diesel suburbans used a 34 inch core so you could probably trim the core support to fit the 2013 radiator. That would be ideal because you could the 2013 electric fans, the 2013 radiator hoses and transmission cooler lines as well. I think the fab work required to get the radiator in will pay off in the long run.

    6. Your existing trans cooler should work fine.

    7. The fuel injection harness can be removed where it goes through the firewall on the passenger side. You will need to disect some of the wires out of the harness that goes to the bulkhead plug on the driver's side. Get a good wiring diagram of the suburban and you'll see what needs to stay.

    Couple of tips I have learned:

    You need to get the A/C pressure transducer from the 2013 and install it in the suburban for the cooling fans to work properly with the A/C. You will be moving the compressor anyway, just make sure to get the right fitting in the new a/c lines.

    Don't throw away/sell/lose anything until the job is done!!!!

    Ask a lot of questions, go slow, and enjoy the project.
     
    Nicholas_nolte81 likes this.
  3. Nicholas_nolte81

    Nicholas_nolte81 Registered Member Premium Member

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    So I went ahead and got a bunch of major parts on order. I bought a quad headlight front clip with the correct core support so it'll have room for the bigger radiator and also make the truck look better.

    For the coolant sensor I found a 3 wire unit that fits into the passenger side block. It's a sender and sensor in one so that should be awesome.

    From looking at the photos I think theres a way I can mount an oil sender on the side of the cooling line

    https://www.amazon.com/dp/B004AFC7B...UTF8&colid=1Q8WL3VQCU30U&coliid=IJCO5K1UDB2QI

    I'm trying to reuse all of the suburban AC parts. I got the brackets that reuse the R4 compressor. The guy who reworked the LS harness is gonna walk me through the AC install as soon as Im ready.

    Thanks for the help!
     

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