LS376 / 480 With 4L80E

[BigShoe24]

I'm about to wire up my starter and alternator. Does anyone have a link or diagram for the best way to do this. I want to keep the wiring minimal and appreciate any suggestions anyone has.

[BigShoe24]

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[Bennett68C10]

Looks great
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[BigShoe24]

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Thanks, it's getting closer
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[Bennett68C10]

How much did you have to modify the cab floor to get that big ole 4L80E to fit?
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[BigShoe24]

Pretty substantial, but I raised the tail shaft of the trans quite a bit so the motor sat more even.
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[ripdog28]

Originally Posted by BigShoe24

Pretty substantial, but I raised the tail shaft of the trans quite a bit so the motor sat more even.
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Just make sure your driveshaft/ rear diff angles are acceptable while driving. Straight line can be bad. Here is some basic info if needed.

I really like the build so far.

[BigShoe24]

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Looking to by a set of the DD's VHX-1014's; anyone running them or have recommendations?

Thanks,
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[mcmlxix]

I just bought the carbon/red factory style setup for my 72' Blazer... not intalled yet but they look great... and you can add modules (compass/air temp, trans temp, EGT, PRNDL and others) Are you building a custom dash?

[BigShoe24]

Just ordered a set; hopefully they'll be installed in the next few weeks.
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[mej005]

I have a set of the dakota digital VHX's for my 64-66 dash and they are awesome, especially for an ls swap. Setup was very easy to do, and all the adapters and sending units are there to mount them in whatever engine you have, and they have the modules to add just about whatever you want including the ODBII to run the gauges if you don't want to use the sending units.

[BigShoe24]

So I've got everything wired and ready to rock. I'm adding fluids and am wondering if anyone could suggest what transmission fluid to use. I've read around a bit and it sounds like a Dexron 6 would be best but still unsure as to brand or if something else comes into play. I'm running a 4L80e.

Thanks

[BigShoe24]

Can anyone offer advice regarding oil priming? I read to pull the plugs and turn the motor over with the starter until I get oil pressure. I did this and am not getting any pressure. I also read that many times this method doesn't create enough pressure to get a reading and that the motor needs to start to get pressure. Any help would be tremendously helpful.

Thanks
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[BigShoe24]

Sorry to keep posting but I'm not getting anywhere on the oil priming/pressure issue. I read of a few people putting something like 17 Quarts of oil in there to prime it and then drain and replace with correct amount. This seems a little ridiculous but I am getting a little worried about cranking on my motor multiple time without my gauges ever reading any oil pressure.

I'm sort of at a loss so any input would really be helpful. Thanks
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[ls1nova71]

Do you have a mechanical gauge or electric? If it's electric, make sure it isn't losing power during cranking and giving you no info. I have had to overfill an engine to get oil pressure before due to the fact that the oil pump is located up front of the engine, and with a completely dry pump, they can suck air rather than oil. Overfilling it submerges the pump in oil, so it can't suck air. 17 quarts sounds extreme though, I think I used 10 or 11, then drained it and put the plugs back in before starting.

[Jon01]

Pop the sending unit and crank it. I bet you'll find that you're getting oil pressure but the gauge is switched off during cranking.

[68GMCCustom]

I had the same problem when installing my "new" LY6 crate motor after cam change/removing VVT...even took it back out and pulled the pan to go over things. Finally took the advice of many and relied on the assembly lube and just fired her up. To my relief the oil pressure came up almost instantly.

If its a used one that's been sitting for a while there's no assembly lube to save it....so:

GM has a priming kit that's expensive I understand:


or if you see yourself doing more LSx swaps buy this for $79.95:


https://www.mdrtuning.com/content/x-...p-priming-tool

[BigShoe24]

So I finally got oil pressure! I also turned the motor over and got it to fire several times for 2 to 5 seconds but it kept quitting on me. Any ideas? Everything sounds good for those initial few seconds and then it just shuts off. I'm going to make sure all the wiring is good and my grounds are clean but other than that I'm not really sure.

As always, thanks.
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[Last_Paladin]

Originally Posted by BigShoe24

So I finally got oil pressure! I also turned the motor over and got it to fire several times for 2 to 5 seconds but it kept quitting on me. Any ideas? Everything sounds good for those initial few seconds and then it just shuts off. I'm going to make sure all the wiring is good and my grounds are clean but other than that I'm not really sure.

As always, thanks.
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What tune do you have on the computer? VATS still enabled?

[ls1nova71]

I agree, sounds like VATS....
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[BigShoe24]

I purchased a complete harness from Speartech. After reading about VATS I would be surprised if that's what it is, or rather frustrated.

Any other thoughts? I'll keep at it and maybe it'll fix itself, lol!
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[Last_Paladin]

Originally Posted by BigShoe24

I purchased a complete harness from Speartech. After reading about VATS I would be surprised if that's what it is, or rather frustrated.

Any other thoughts? I'll keep at it and maybe it'll fix itself, lol!
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Harness doesn't mean they touched the computer. Did they do a tune on it? Why don't you tell us a few things, like is this a speed density tune, MAF with 02's, what?

Let's check the basics then: Do you have spark? Do you have fuel/fuel pressure? All the gauges reading correctly? All the senders there?

Do you have more than 11.4v in the battery? Is the alternator charging? Have good oil pressure?

[BigShoe24]

Well fortunately it turned out to be from me running it with straight headers and no exhaust. I guess the ECU was making it run rich due to no back pressure and an inaccurate reading on the O2's.

Now on to the getting the power to the ground. What type of drive shaft are you guys running? My 4L80e came with a bolted on yoke and I am wondering if this can simply be unbolted to provide for a slip yoke style set-up?

Thanks,

[BigShoe24]

So I believe I've found a good option for a Drive Shaft... Here is a link.

http://www.dennysdriveshaft.com/p136..._and_slip.html

[Jon01]

Any driveshaft shop should be able to set you up but that seems reasonably priced.