Alright guys, reason im asking here is because ive search but am getting different ideas on the best year 4l80 to get. Some say places say pre 99, others are sayin post 99. The trans is getting swapped into my 4th gen, and just tryin to make sure i get the best 4l80 out there. Thank you.

 

https://ls1tech.com/forums/automatic...235-4l80e.html

 

A newer version seems like it would have newer parts, possibly fewer miles, and probably more fixed internal problems (over the year corrective parts work their way in). Anyone telling you to get an older trans is either trying to race you (and hopes you break down) or wants all the late model trans for themselves (damn trolls).

 

Are you trying to find a good core? Anything rebuilt by a good shop could be upgraded fully.

 

The trend is towards stock units with shift kits, as opposed to built versions.

Built versions tend to contain mistakes. As fellow member "clinebarger" once said, "mostly builder mistakes".

 

The basics to make a 4l80e live seem to be, dual feed mod whether through internal mods or an Hd2 kit, input shaft for higher hp, and a good stock rebuild. That's basically it.

 

I think the "builder mistakes" being mentioned refer to the potential to replace damaged hard parts with parts from other years and though they go together, the clearances are not right, or they are different in other aspects. It's kind of hard to make mistakes if you are tearing a unit down, and then putting it back together without replacing any of the hard parts. The planetaries can be rebuilt with kits from Sonnax so no reason to swap these parts out and potentially create a mis-match scenario. There are 2 distinct center supports and putting the wrong C/S into your trans will surely kill it quickly. Putting an early C/S into a late trans will not allow the rear cooler line fitting to be installed. However, you can put a late C/S into an early unit by accident and have an internal leak that will be catastrophic to the unit.

The 80E's are known for being extremely hardy, strong, internally heavy units. The biggest problem I see with them is that people are trying to spin them well into the 7000 RPM range and then shift them really hard. The internal drums & gear train are REALLY heavy and hard/fast shifts at high RPM's is not the 80E's forte and will tear it apart from the inside. I always caution people to keep their max RPM shifts <6500.. Low RPM, high torque applications is where the 80E shines. Smaller cube motors, that are naturally aspirated that have to be revved to the moon to make any HP are generally not the best place for an 80E-IMO.. Your results may vary. The Super Drum can help in this regard, but only to an extent.

Also, there is NOTHING wrong with building 80E's up internally. Rollerizing the gear train, increasing clutch count in the forward, direct, and intermediate sections has no draw backs as long as you keep your clearances correct. Dual feeding is a fool proof way to make this unit stronger. Wider bushings in the sun gear tube is also recommended as these bushings are always shot when checked during a tear down. The sun gear tube bushings is a place where builders truly can make a mistake that can kill the unit. Later model units 97+ with spaced out cooler lines REQUIRE bushings with lube grooves in them. Early model units must utilize bushings in this location that have NO LUBE GROOVES. Also, the output shafts are unit specific as the early one will have a lube hole in it, and the late one will not. These issues usually pop up when people are trying to replace hard parts.

I like 1 piece teflon (non scarf cut) sealing rings on the center support. The later model plastic sealing rings that come in the rebuild kits are satisfactory but if you vacuum test a center support with a direct drum on it with the only change being the sealing rings, the teflon sealing rings will always give higher vacuum readings than the plastic ones. It is also my opinion that the teflon rings are less likely to ruin the seal surface inside the direct drum as long as the bushings in the sun gear tube, and the center support bushing are in good shape and keep the sealing ring lands from making contact with the inside of the drum.

The other thing that I see a lot of is people drilling the feed holes in the separator plates too large trying to make the shifts really hard. Sure you may think it's cool to chirp the tires every time it shifts but your u-joints, axles, rear differential internals, and trans internals are going to show you just how much they dislike it. You can see the results of this when you find broken accumulator springs, and damaged plastic accumulator pistons. The Trans-Go HD2 kit has very good recommendations on feed hole sizes. Resist the urge to go larger than what they recommend. Larger is certainly not better in this area.

The billet shafts that are available are good insurance as long as you get a quality shaft. There are many "China" made shafts on E-bay for what seem like good prices. The reality is that they are weaker than the factory shafts as they are made from inferior metals. If you are going to get a billet shaft, buy it from a reputable source with a known name in the industry.

So, my whole point was.... this idea that "built" units are more likely to fail than a stock unit with a shift kit installed holds no water in my mind. Either scenario will fail given enough high RPM shifts. Either scenario will fail if the heat generated from a high stall torque converter is not controlled. Either scenario will fail if the tune is off, for any of various reasons. All else being equal-a properly "built" unit can't possibly be any less reliable than a stock unit with a shift kit.

 

Thanks for the info and typing it out.

 

That was an amazing post.

The only reason I always caution against building anything is because you can't trust people to do anything right it seems.

Some people have spent $10000 trying to get the 4l80e sorted, I didn't want to be like that, or recommend something to somebody that would create that:
http://www.supraforums.com/forum/sho...E-out-of-state