04 LM7 into 87 K5

K5Rob · Sunday at 9:33 AM

Hey all, I want to pull the LM7 5.3 (dbw) of my 04 2wd and drop into my 87 K5. My plan is to use the existing 700r4 and existing transfer case (both fresh rebuilds) in the K5 and use a manual valve body and ratchet shifter. I think this will be a fun set up. For torque converter lockup I was planning to use an automatic 4th gear lockup kit from TCI.

For the PCM, I am wondering about the VSS signal and if it is actually required for the above set up?

Also is the Brake Switch Signal required since I will be handling lockup on its own?

Lastly, will it matter to the PCM if i am in 4wd or not since I am using the K5 transmission/tcase?

My thought was I could have the PCM tuned for “manual transmission” and the above questions would be non issues. What are your thoughts?

Vbb199 · Sunday at 7:39 PM

K5Rob said:
For the PCM, I am wondering about the VSS signal and if it is actually required for the above set up?

Also is the Brake Switch Signal required since I will be handling lockup on its own?

Lastly, will it matter to the PCM if i am in 4wd or not since I am using the K5 transmission/tcase?

My thought was I could have the PCM tuned for “manual transmission” and the above questions would be non issues. What are your thoughts?

1. Shouldnt be, since lockup will be controlled externally. Vss is needed for cruise and lockup and some other ABS/TC stuff... not needed

2. Brake switch signal might matter, as the pcm "may" use that signal to adjust timing and fueling when you brake. Theres parameters within it called brake torque management, but i dont think it'll matter.

3. The 4x4 switch signal somewhat matters, as torque calculations and their respective tables within the pcm are used based on the programmed gear/tranfer case ratio's , however most people dont even bother with it lol .

PLenty of people use LS motors in a swap project with a standalone PCM, mated with a manual trans..

A tuner can help you resolve all of that.

K5Rob · Sunday at 7:49 PM

Vbb199 said:
1. Shouldnt be

Thank you for the reply and taking the time to spell everything out.

Do you know if the oil pressure sender is required for the pcm? I wanted to take it out and replace with my k5 sender to keep the factory gauge.

Also I need a key hot in crank source on the K5. What location are people using for this on our trucks.

I think that’s it for now. Thanks again. Huge help.

Ricko1966 · Sunday at 8:11 PM

K5Rob said:
Thank you for the reply and taking the time to spell everything out.

Do you know if the oil pressure sender is required for the pcm? I wanted to take it out and replace with my k5 sender to keep the factory gauge.

Also I need a key hot in crank source on the K5. What location are people using for this on our trucks.

I think that’s it for now. Thanks again. Huge help.

Hot key in crank position,use the starter solenoid exciter wire.

Vbb199 · Sunday at 8:12 PM

K5Rob said:
Thank you for the reply and taking the time to spell everything out.

Do you know if the oil pressure sender is required for the pcm? I wanted to take it out and replace with my k5 sender to keep the factory gauge.

Also I need a key hot in crank source on the K5. What location are people using for this on our trucks.

I think that’s it for now. Thanks again. Huge help.

I did forget to add, you'll need to definitely have the PCM programmed as a manual.. theres multiple parameters involved but the simplest one to justify the reprogramming is, with no PRND switch present, the pcm will think its in park or neutral all the time, and wont let it rev beyond 4000 or so. Whatever default is for P/N

Not sure about the oil pressure switch, some motors need that signal for cam adjustment, but i dont think your 04 does. Maybe the fuel pump? Im not a gmt800 person honestly..
I just know the PCM, motor, and trans combos thats within them well.

K5Rob · Sunday at 10:43 PM

Vbb199 said:
I did forget to add,

Thank you, yes I will have it tuned as a manual. I think I have someone lined up to do the tune

K5Rob · Sunday at 10:45 PM

Ricko1966 said:
Hot key in crank position,use the starter solenoid exciter wire.

Sorry, I think I meant hot with key on AND crank. Need a source for PCM. Was thinking one of the fuses under the dash

CalSgt · Sunday at 10:58 PM

K5Rob said:
Sorry, I think I meant hot with key on AND crank. Need a source for PCM. Was thinking one of the fuses under the dash

There’s a few circuits in the cab hot while cranking, under the hood I think the coil wire should be hot on run and start. Get your test light out…

K5Rob · Monday at 11:48 AM

Okay thanks all. Time to get to work

K5Rob · Monday at 1:38 PM

For those of you that kept the 700r4, did the stock LM7 oil pan clear the crossmember?

K5Rob · 2024-12-03T16:06:39-0500

Also wondering the above question but with a 4L60E. I think the 4L60E is the preferred transmission over the 700r4 but will it move things around or fit in the stock location? This would be with the original 208 Tcase and an adapter.

Vbb199 · 2024-12-03T17:03:43-0500

K5Rob said:
Also wondering the above question but with a 4L60E. I think the 4L60E is the preferred transmission over the 700r4 but will it move things around or fit in the stock location? This would be with the original 208 Tcase and an adapter.

SHould be the same length as a 700r4

The 208 will mate to the 700r4 or 4L60e

Both 27 spline output , 4 bolt pattern

K5Rob · 2024-12-03T17:16:12-0500

Vbb199 said:
SHould be the same length as a 700r4

The 208 will mate to the 700r4 or 4L60e

Both 27 spline output , 4 bolt pattern

So then in theory if I ran the 4L60E I shouldn’t have to change D/S length, and I think the mounts I found will work with the factory crossmember.

If I run the 4L60E, doesn’t the PCM need to know if I am in high or low range? (Additional sensors/wiring for the 208?)
I do know it will need a VSS signal and brake switch signal at a minimum.

The 700 seems like a simpler swap to avoid a lot of this, am I missing anything?

Vbb199 · 2024-12-03T19:55:31-0500

K5Rob said:
So then in theory if I ran the 4L60E I shouldn’t have to change D/S length, and I think the mounts I found will work with the factory crossmember.

If I run the 4L60E, doesn’t the PCM need to know if I am in high or low range? (Additional sensors/wiring for the 208?)
I do know it will need a VSS signal and brake switch signal at a minimum.

The 700 seems like a simpler swap to avoid a lot of this, am I missing anything?

Yea, this gets into what every LS swapper faces... the issue with 60e/80e swapping is you NEED vss , and if 4x4 you'll need your hi/lo switch off the t case

The expensive solution (due to rarity) is to run a passengers side drop NP241 OR 208 from a 90 or 91 suburban , (maybe k5?)
Which has vss.

Then run a 90/91 burb/k30/k5 electronic speedo instrument cluster .

Optionally---

You can visit dakote digital for a adapter to turn the cable speedo output on your 208 to VSS .... ORD might have also, idk.

The 700r4 is the easiest, cheapest methos (go on fleabay and price a np241 or vss 208 and you'll see why)

K5Rob · 2024-12-03T20:17:17-0500

Vbb199 said:
Yea,

This is the down and dirty info I have been looking for so thank you for that. I was worried the 4L60 would nickle and dime me to get everything working correctly. I dont have a huge build budget. I think I have the 700 figured out and can keep the speedometer which is a plus. Its also a fresh rebuild so I’d like to use it. Now Im just hoping my stock oil pan will clear the cross member but worse case I will have to notch.

04 LM7 into 87 K5

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