ok guys, i need some fresh ideas on this...

'01 silverado 1500, 5.3, 4wd

it was taking forever to lock up in overdrive over 50mph, i flushed the transmission and changed the filter, didnt help. i took out the tcc solenoid, tested it, cleaned it and checked over the valve body well. after that it worked great for 6 weeks, about 2-3 seconds after shifting before lockup. by then i knew it was mechanically sound and not slipping, then it started again. i put a new tcc solenoid in there even though the previous one checked ok on the bench, thinking maybe it was a heat thing. rode around with the modis on there for a while, when it showed locked, it was imediatly locked. then when it started up yesterday, i had decided it was a computer problem, but then when i put the modis back on there, it showed locked 2-3 seconds after shifting into od, but it took upwards of a minute to lock. there are no tsbs on this and no other test procedures i can think of to check the system while its being driven, since the problem never shows itself when i have the damn thing torn down.

i know someone here has an idea floating around in their head that isnt in mine at this point

2/16/2006 12:00:12 PM

*crickets*





dont you have any buddies at a real transmission shop?

2/16/2006 8:24:02 PM

called the place back home i used a lot, but they had never heard of a 4L80E lasted 190,000 miles, much less long enough to have this kinda problem, startin to think its just a combination of things, its been tryin to kick the bucket for the last 10,000 miles, but i wont let it die without a fight.

2/17/2006 1:45:14 PM

Usually, the problem I think of is when one doesn't want to come out of lockup. Some lockup converters are naturally locked when no fluid pressure is applied to the clutch assembly. When fluid pressure is applied, the lockup clutch disengages.

If I remember correctly, dirty orifices and sticky solenoids usually result in a converter that may lock up but refuse to come out of lockup. But you've already approached that avenue, and your symptoms are exactly the opposite. Are you sure you don't have any blockage in the valve body? A check ball missing or not seating properly?

Have you actually removed and split the valve body to clean it? Sticky spool valve?

In reality, I don't know shit about the 4L80E...maybe a bit more on the 4L60(E)/700R4.

2/17/2006 1:57:59 PM

a 1500 has the 4L60E, 3/4 ton trucks have the 80

2/17/2006 2:45:01 PM

^ 1500 HD, 3/4 ton suspension, 1/2 ton frame, still a small 5.3 (6.0 was an option in the 1500 HD in late '01), 4L80E, 12 bolt. you should try finding parts for that damn thing. i think thats why its hanging on so damn long, not enough power for an overbuilt drivetrain.

2/17/2006 8:11:00 PM

man that is a strange combination! Is it a 12 bolt or a sf 14 bolt (9.5" ring gear)?

2/17/2006 8:13:45 PM

its a 12, i have been trying to find a matched gear set but its damn near impossible, so bigger tires are gonna suck around town. thats been one thing thats been holding me back right now.

2/17/2006 11:21:43 PM