5.3 swap with 4l80 transmission
 

I am thinking about doing an LS swap into my 71. I found a 5.3 motor with a 4l80E transmission that is in a 3/4 ton 2000 model truck that was wrecked. Is that transmission OK? I've heard that it's better to go with the 4l60 since it's lighter. I don't plan on modifying the engine at all.

Any comments or suggestions are appreciated.

Thanks!

Re: 5.3 swap with 4l80 transmission
 

Yes a 4L80E is actually a stronger transmission and you should be fine with that combo.
The extra weight won't hurt you.

Re: 5.3 swap with 4l80 transmission
 

What did you use in yours?

Re: 5.3 swap with 4l80 transmission
 

I have a 4L60E in mine. But if I had the chance to get a 4l80E I would be all over it if the price is right. I only used the 4l60 because it was cheap.

Re: 5.3 swap with 4l80 transmission
 

I have never seen a 5.3 in a 3/4 ton. I'm not saying it is'nt possible but I'm pretty sure that the 3/4 ton standard motor is the 6.0. I'm not one to say my knowledge is the final say but I do build later model chevy trucks [and GMC's too] for a living and owned quite a few and looked at thousands of them wrecked and I 've never seen a 3/4 5.3. Either way the engine trans combo is awesome and you will be very happy with either one I would say.I have put a 6.0 4l80e in my 68 LeMans convert and a 5.3 4l60E in my 89 C1500 loved them both. Also, depending on who reflashes your PCM for your truck, it will open up some HP and torque just by changing a few maps inside.

Re: 5.3 swap with 4l80 transmission
 

So maybe he doesn't know what he has and it's a 6.0?

Re: 5.3 swap with 4l80 transmission
 

It could have been changed out to a 5.3 ,they are quite a bit cheaper[by about 1000] to buy used. I did think of that but I did'nt put any of those thoughts in type

Re: 5.3 swap with 4l80 transmission
 

Would the computer and everything else need to be changed out if the motor was swapped for a 5.3? He wants $700 for the motor and trans and seemed like he would give me whatever wiring, etc I need. The truck only has 122,000 mile son it, so I would be surprised if the motor was already swapped out. I suppose stranger things have happened. Something goes wrong with an oil pump, or someone runs it out of oil...

Re: 5.3 swap with 4l80 transmission
 

I would buy that combo for $700 that is a good price.
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Re: 5.3 swap with 4l80 transmission
 

4L80E is stronger, heavier, larger and has more parasitic loss (HP to the rear wheels). I personally think they are noiser too.

Re: 5.3 swap with 4l80 transmission
 

My engine came out of a 2000 3/4 ton, 5.3 4l60, has the tag on the cowl to match. I was told the only 5.3's that had the 4l80 were in vans....

Re: 5.3 swap with 4l80 transmission
 

well as I said I have never seen a 5.3 in a 3/4 ton I have also never seen a 4l60e in a 3/4[ in that body style]. The van gvw's are rated a little different and they did have different motors avaible. I have seen 4.3 v-6's with a 4l80e behind it . One of the moving companys had some built[they have yellowtrucks] it will be easy to determine as all it takes is to look at the motor ,the size is stamped on it on the back and the sides. and no pcm or wiring would have to be changed out to work. In fact you can take out a 4.8 and replace it w/5.3 or 6.0 or vice versa. it won't run perfect I would suggest a reflash but it will go.

Re: 5.3 swap with 4l80 transmission
 

I will step in the kitchen for a knife and fork to eat some crow after my last post where I once again said I've never seen one I went to GM parts express and plugged in a 00 model 3/4 and it does list the 5.3 I was WRONG and I am sorry if anyone was messed up in any way from my misinformation

Re: 5.3 swap with 4l80 transmission
 

tastes like chicken!

Re: 5.3 swap with 4l80 transmission
 

Ive had a plate of that more than once in my life :lol:

Re: 5.3 swap with 4l80 transmission
 

I wish I had ten bucks for everytime I was wrong!!!!!!!!

Re: 5.3 swap with 4l80 transmission
 

I could retire if I had $10 for every time I was wrong:)
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Re: 5.3 swap with 4l80 transmission
 

It was an option in 1999 & 2000 to have a LM7 5.3L in a 2500 truck. 5.3L's were never offered in a 2500HD truck. Ive never seen one in a 2500 truck either.

The 5.3/4L80E combo is a whole other can of worms......

99 & 00 LQ4 6.0L are different than 01 & up 6.0L's, The rear crank flange is longer than any other gen III engine, Also the only one to have iron heads.
The longer crank flange was designed for use with the 4L80E transmissions converter spacing. 01 & up LQ4 6.0L's use a spacer to deal with the converter spacing, Because the LQ9 came out with a 4L60E/4L65E

So does a 99/00 2500 LM7 5.3L have a MT1 4L80E behind it.....I dont think so. It would have 4L60E..........Untill someone can show RPOs LM7 & MT1 on the same RPO sheet.....There is no proof.

Re: 5.3 swap with 4l80 transmission
 

I'm going to go look at it tomorrow, so we'll see if I can figure out what's what.

Re: 5.3 swap with 4l80 transmission
 

The passenger side of my trans has 4l60 raised on it, should be easy to spot.

Re: 5.3 swap with 4l80 transmission
 

I have a 5.3/4l80e combo in my blazer. It isn't the best combination for power or fuel mileage but if you ever decide to add some boost it is one of the best combinations to have.

Re: 5.3 swap with 4l80 transmission
 

Agreed, I too have a 5.3/4L80e combo (bought seperately). Although I get 18-19 hwy and 12-14 city.