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Going from 700 to SM465, few questions before I start

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BayouBlazer88, Jan 2, 2005.

  1. BayouBlazer88

    BayouBlazer88 1/2 ton status

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    I'm sure this has been covered several times but I cant really find anyone who has done this swap in a tbi blazer. Anyway, I already have the transmission and TC from my buddy's 84 blazer as well as everything from his converted hydraulic clutch setup so there wont be any hunting for the right parts. So here goes:

    1) My blazer is an 88' with a 350tbi, did the 700's in these have electronic lock-up torque converters? and if so, will the absence of this cause any computer problems? And what do I do with the wire that goes into the transmission, just cut it off and seal it?

    2) Will the engine run fine with the manual transmission with the stock computer chip or do I need to consider getting a custom chip?

    3) Do I need to get another radiator or will I be fine just plugging up the tranny cooler lines?

    4) What do I do about the shifter and sleeve on the steering column used to select gears in the auto, is there a way to get that off without removing the entire column?

    That's all I can think of for now, but please give me any other tips and recommendations, especially those of you who have done this before. Thanks for the help
     
  2. fortcollinsram

    fortcollinsram 1/2 ton status

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    Yes your 700r4 had a lock-up converter but it will not cause any problems. When I swapped in my 465 in place of my 700r4, I just removed the entire tranny wiring harness from the truck

    The truck will run just as it did with a manual as it did with an automatic. One thing you will have to hook up though that will take some work is the VSS (Vehicle Speed Sensor) UNLESS you are keeping a np208 t-case. I swapped in a 465 tranny with a 205 t-case and the 205 was not setup with a reluctor ring for the speed sensor like the 208 was. If you are keeping the 208, this is a non-issue. I have yet to hook up my VSS and it has been 2-1/2 years since my swap and since then I have even swapped in a TBI 454. There will be some driveability problems, albeit minor problems, and the possiblilty of kicking the SES light on with out the VSS hooked up. IF you are going to a np205 t-case, you will need to pick up a VSS from a place like www.jagsthatrun.com that goes inline with the speedo cable and has a hookup for the VSS wire. A custom chip is not needed as the same ECM's were used in truck that had both manuals and automatic transmissions.

    Your old radiator will work just fine! Either plug the cooler lines or run some engine-oil cooler line to those ports and you will be fine.

    This is another issue I have yet to take care of. You can remove the pin that hold the shifter on or you can get a new column. In my case, I still have the shifter on b/c I have yet to wire in my Park/Neutral swith or my reverse lights so I still use my column shifter to put my reverse lights on. I just need to sit down and figure out what two wires are for the P/N switch and which ones are for the reverse light and run them to the tranny switches.


    I hope this helps. The only wiring you have to worry about though is the P/N switch and the reverse lights and the VSS sensor if you are swapping in a np205 instead of a np208. Other than that, it is a bolt in deal with the exception cutting the hole in the floor for the shifter and the hole in the firewall for the clutch master cylinder.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    All VSS up to 1990 on our trucks are cable driven at the speedometer head.

    I know you did the swap, but no 205, 208, or 241(? not sure when they came out) had a reluctor ring in them until 1990, there was no need without the digital speedometer.

    Now that is to the best of my knowledge. You've done the swap in a vehicle I have not physically touched.

    Someone correct me if what I know to be true is not. 1990-91 are the only years with electronic speedometers, (no speedo cable) everything prior uses a cable, and VSS is off of the speedometer itself. 1990-91 use a DRAC, and with DRAC came the reluctor ring on the t-case.

    I'm assuming this was in your '87, I just feel I'm missing something based on the years you are talking about here because you are so sure and have done it.

    However, one thing that needs correction is that the PROM is different between manual and auto applications. ECM's are the same ('747 IIRC for TBI trucks) but the PROM setup is ALWAYS different auto to manual. Different target idle, different fuel trim, throttle following, etc. You need a manual PROM to get rid of the park neutral issue as an example.
     
  4. bigblock44k5

    bigblock44k5 1/2 ton status

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    You should be fine all around except you might get a check engine light due to the conver lockup not being connected. It should run the same as in 88 the engines arent dependant on signals from the tranny. You will be fine taking the shifter off, you will still be able to move the column shift with your hand for reverse lights if you need to. The handle itself is what locks the column(when you pull it toward you then move it)so with it removed you can move it all day long. Your radiator will be fine, just plug the hols so nothing gets in there just incase you plan on using it someday.
     
  5. NJBLZ

    NJBLZ 1/2 ton status

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    park/neutral start and reverse lights

    There are a purple and a yellow wire going into a switch at the bottom of the column on automatics. Moving the column shifter to park or nuetral completes the curcuit and allows the vehicle to start. On a manual trans truck the purple and yelllow wires are routed to a switch on the clutch pedal, so it will only start when the pedal is pushed down. Splicing the wires together will bypass these systems, allowing it to start anytime, as long you put the key in and turn it.

    There should also be a light green and a dark blue wire going into the same switch at the bottom of the column, these are for the reverse lights. On a manual trans truck these were routed to a switch on the trans. You can re-route them, and try to make the the switch on the trans work, or you can wire them up to a toggle switch on your dashboard so you can turn them on whenever you want. The green is the feed TO the reverse lights, the blue is From an ignition hot curcuit.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    IIRC the reverse light harness actually has a connector inline, so you shouldn't need to cut/splice that at all as long as you can find a manual transmission end.

    The connector changed later on from something like the license plate lamp connector to a weatherpack. I need to check the 465 going in my truck (someday soon I hope) as I believe it is the new style connector, which means I can probably get rid of the old style one I have, if someone needs it.
     
  7. BayouBlazer88

    BayouBlazer88 1/2 ton status

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    Well I want to connect everything correctly. I want both the neutral safety switch and reverse lights to be connected and working properly. I don't want to have to turn on some toggle switch or shift the old auto column shifter in order to turn the lights on. I want to be able to just shift to reverse and thats it. And I know my dumbass would forget about the neutral safety switch and try to start the motor in gear or without the clutch pedal pushed in and destroy the starter or flywheel so I'd really like to have that connected. Is connecting the switch a PITA?

    Also, about how much do PROM chips cost and are they carried regularly at places like Autozone and Oreilly? And are they contained in the same box as the ECM (behind the glovebox)? Will using the original one give me any problems?

    Also, I am definitely keeping my 208, meaning I won't have to worry about the VSS problem, right?
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    VSS won't be a problem.

    As to the clutch switch, I HIGHLY recommend bypassing it.

    I like doing things right as well, but one other big advantage of the clutch setup is that if the rig dies for some reason, you can still go to 4low and low in the tranny, and move the rig around via the starter. I wa sable to get my rig pointed downhill which allowed me to compression start it one time...that saved me a LOT of hassle considering I was in the middle of nowhere, alone.

    It will let you know if you try to start it in gear, you won't get far before you notice if you forget to depress the clutch. : ) It won't hurt anything the couple of times you do it.

    No idea on the cost of a PROM. Perhaps someone in the for sale section has a 465 ECM you can buy for $50 or something.
     
  9. BayouBlazer88

    BayouBlazer88 1/2 ton status

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    Well I live in one of flattest states in the Union, Louisiana, so I doubt I'll get stuck anywhere where gravity can help get me closer to my destination. If I do get stuck somewhere I can just call a tow. But is the neutral safety switch difficult to connect? If it's really that much of a pain, then I'll just bypass it. But don't you just have to connect the purple and yellow wires to the NSS as NJBLZ suggested? Seems like the most difficult part is finding those wires inside the column shifter assembly. I already have the switch and pedal assembly, so not much hunting for parts.

    Also, I think I'm confusing the PROM and ECM. Which one is in the metal case behind the glove box, or are they both in there? And do I need to change them BOTH out for optimal performance?
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    First off, try pushing your Blazer ten feet uphill no matter how steep. :)

    The NSS in the clutch setup is kind of like the brake light switch. It is activated right off the pedal. No it probably isn't a hassle to hook up. Sounds like you just may need the wiring connector to the switch itself. It's only there because GM's lawyers figured you were too stupid to push in the clutch pedal, and would sue them if you did something because of your stupidity. (Kind of like third brake lights) In any case, it's helped me out, and I know full well one person can't push my K5 over the bumps in my driveway, so the idea of being able to move it 5 feet with the starter is a no-brainer. BTDT, leaving $10 switch out saved me how many $$ in a tow?

    Both the PROM and the ECM are in the same case. The ECM is essentially the board that the PROM resides on. The PROM is calibrated to the application, but the ECM would stay the same. For instance a 1987 700R4 truck and 1991 465 truck will use the same ECM, but for sure the PROM would be different.
     
  11. darkshadow

    darkshadow 1 ton status

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    it is not hard, it you have the pedle set then you will see at the top of the clutch there is this little plastic box with a punger, it has two prongs hook your wires to it.

    when you depress the clutch it compleats the circit
     

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