5.3 issues

FearlessAZ

Original poster
Member
Jun 7, 2016
156
Phoenix, AZ
So I have my eye on a SWB 5.3 TB LT here and had a couple questions.

Does the 5.3 have any issues that are fairly common? I know 4.2 was pretty solid with the occasional thermostat or temp sending unit or even the fan clutch. Anything I need to look for specifically with that motor when I go to look at it?

Is the 4L60E the same in both TBs? Or would it be different since one is 2wd and the other is 4wd?
 

Sparky

Member
Dec 4, 2011
12,927
Depends on the year. Some have AFM, which can result in oil usage. I have AFM on my Silverado's 5.3 for example. I tuned it out and it fixed my oil usage. Other than that, there's usually not much that goes wrong in those that I'm aware of. 167k and counting on mine!

The guts of the 4L60E are basically the same on them. Bellhousings are different. A 4WD model is going to be different due to the transfer case bolting up to it vs a tail shaft housing on the 2WD model.
 

FearlessAZ

Original poster
Member
Jun 7, 2016
156
Phoenix, AZ
The one I am looking at is a 2006.

Good stuff to know. I was hoping I could swap the 4L60E that is currently in my TB because it was freshly rebuilt last year with a couple goodies. Looks like I can just drop it and sell it by itself.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Yep, it would have DoD/AFM and they suffer from oil use and lifter failures. If you disable it before failure, it should be fine as it would normally fail when in 4 cylinder mode trying to go back to 8 when the lifter would jam collapsed. It can be tuned out but can be easily turned off temporarily:
How to disable AFM/DOD at no cost

When checking it out, rev the engine moderately and listen for some knocking between 2-3000 RPM. Same under moderate acceleration. Mine is currently doing this but it has been forever. Thought it was the valvetrain and it wasn't (after spending over $1000 :mad:).

Check for popped exhaust manifold bolts and cracked manifolds with leaks. Apparently the passenger side is prone to cracking.

Other than that, it's the usual GMT360 stuff.
 
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FearlessAZ

Original poster
Member
Jun 7, 2016
156
Phoenix, AZ
I was never aware that the 5.3 had AFM. Learn something new. I would most likely get it tuned out and converted over. Is there a noticeable drop in MPG?

Very good stuff to look for, Moose!
 

Sparky

Member
Dec 4, 2011
12,927
I didn't see a drop worth mentioning. Theory sounds good, practice AFM seems uesless!
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
GM's own literature says it saves a whole 5% more. Oooooh, ahhhhh. So if you are getting 20 MPG, it will gain you a whole 1 MPG. Although I have no numbers for the Saab, my '11 caprice 6.0L with DOD disabled dropped .5 MPG. I remember on the Saab before I disabled it would kick from 4 to 8 cylinders like nothing. Just an oh so slight acceleration would do it. In city driving, it's useless.
 

FearlessAZ

Original poster
Member
Jun 7, 2016
156
Phoenix, AZ
So everything sounds good then. I might even have the wife already on board with it. If they still have it this weekend, I will go check it out.

Thanks guys!
 

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