4L60E -- Astro 4.3 vs K1500 5.7

a_kelley

a_kelley

mechanical fixer
Joined
Jan 26, 2010
Location
Rutherfordton
What's the deal? I can get a 2000 or 2001 Astro AWD 4.3L 4L60E but it needs to go into a 1998 1500 4wd 5.7L... Is it simply swap the bellhousing? Autozone says its a different transmission for the two, but since both are 4L60E's, what's the deal? I've swapped many a transmission I just don't want to have to get into it to say, oh thats why its different. 4wd and AWD units should just swap out, I believe. Thanks!
 
the electronics are different, some 99 and later models run a pwm style system. '99 converter lock up plates were a woven graphitic lining that can be partially applied without burning up. the lock up strategy of '99 vehicles requires this kind of lining since the computer will lower converter apply pressures until a 30-50 rpm slip is achieved on a full time basis while at cruising speeds.
 
The 98 truck will also be PWM with EC3. I don't know what the output shaft styles are on the Astros but the bell housing should be the same as the 4.3 and the 5.7 are the same bolt pattern. Converters swap over and the v6 converter might be a higher stall but you need to know what the lockup technology was of the donor and make sure it matches.

The 4l60e's of the late 90s had a lot of changes over the years so you need to research what you are getting vs what you have to make sure they work.

I just went though this on my 98 K1500 burb and decided to either rebuild or upgrade. I upgraded to a 4l80e but could have had a good rebuild done for around $1k. Junkyard trans were too high a risk in my opinion.
 
Well, the 4l60e donor is either 00 or 01, and its going to a 99 or 98 1500. So the donor will have graphitic plates in the TC, but is that just an upgrade if the TC just PWMs to full on lock and PWMs off? I don't really want to use the old TC. The donor trans is out of a buddy's van that was rebuilt 60k ago. A stock 4.3 doesn't redline much higher than a 5.7 if I remember right.. I do really want to say its a 99 1500, but I'll double check it and go from there. =) Thanks guys! I'll post back after I'm done and this mess we are supposed to get clears out and I can get something done. lol
 
Astro AWD -> 1500 4WD: swap rear shaft housing.
2000/2001 Astro AWD -> 1998 1500 4WD, same exact bellhousing, trans case, lines, plugs.

Bolt up, plug in affair. Runs out, down shifts, up shifts, TC locks/unlocks, no issues.

Aren't the graphitic plates just an upgrade for the non-graphitic? that's what I saw in looking.. you could get graphitic plates for the older ones, so that my reasoning.
 
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