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Yup! The GM ECU will probably allow you to monitor the trans temperature, so you can keep an eye on it while driving trails. You will be putting in a trans cooler, correct? If you plan on wheeling in the winter snow, adding a thermostatic control to the cooler might be good as fluid can get too cold.
 

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Low viscosity, synthetic Dexron VI probably won't have an issue and the trans controller will probably adjust for temperature, but many OEMs use a thermostatic bypass for the trans cooler for a reason.
 

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Turns out the 6L80E already has a built on cooler thermostat, no need to add one. Not sure if the one that comes with the package has it or not, but it might.

Here's a guy showing how to delete it for use in Arizona:

 

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Discussion Starter #25
Yup! The GM ECU will probably allow you to monitor the trans temperature, so you can keep an eye on it while driving trails. You will be putting in a trans cooler, correct? If you plan on wheeling in the winter snow, adding a thermostatic control to the cooler might be good as fluid can get too cold.
I plan to run a trans temp gauge. I will be reusing my existing tranny cooler and will use a second CBR cooler if it's not enough.
 

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Discussion Starter #26
Fluid will not get too cold...
I don't know how it compares but my 42rle (known for running hot) wouldn't go over 100F all winter driving like an idiot with the supercharger.

One of my dreams is to drive to the Arctic circle in the middle of winter (-40F). I could see on trips like that having to reconfigure my coolers.
 

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Discussion Starter #27
Turns out the 6L80E already has a built on cooler thermostat, no need to add one. Not sure if the one that comes with the package has it or not, but it might.

Here's a guy showing how to delete it for use in Arizona:

That is cool! Hopefully it does!
 

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Discussion Starter #28
I am still a bit worried the 3000 stall isn't going to like going slow enough for rock crawling and provide adequate power at those low rpms and it could keep pegging the tach and breaking traction. The guy I talked to said it wouldn't be a problem and the converter would just slip at those low speeds (...but what does he know about rock crawling...). Does anyone have experience with this? Maybe programming a table for low range would help?

My other option would be going with the LS3 430 if it means better control. But less power = less fun. Lol.
 

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Not sure how a higher stall converter would react rock crawling, I prefer manual transmissions ;). With low enough gear ratios, might not make much difference.

A friend of mine had a '76 CJ-7 with a 401, TH400 and Quadratrac. He had too much cam and would barely idle so I put a high stall converter in it, it ran like a scalded cat on the street, sucked a lot of gas, though. Eventually, I put Rhodes lifters in it to give cam more low end torque and reinstalled the stock converter.
 

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Discussion Starter #30
I talked to Chris at Circle D this morning and he answered all of my questions about which torque converter to go with for my uses and recommended their 278mm torque converter in 2600-2800 rpm stall: https://www.circledspecialties.com/6...p-series-278mm I'll be able to reuse the stock flex plate.

He mentioned this converter would work well for the stock cam LS3 430 and the hot cam 480 (the one I'm planning on going with) and if I supercharge in the future. It will smooth out the chop from the hot cam so it'll still idle and crawl well at low speeds/rpms. The 278mm converter is 11 inches in diameter making it about an inch smaller in diameter than factory which is where most of the higher stall rpm comes from. The smaller diameter will help to transfer less fluid at idle. This will give less pushing at the brakes, because of the cam. The 2600-2800 stall will allow the pedal to feel connected while not being too tight for the cam. This converter is rated to around 550rwhp or 750rwhp if I upgrade the front cover to billet (which could be good if I boost).

It sounds like Chevy "fixed" the choppy cam by installing their 3000k converter which probably works for 99% of their customers who are installing them into hot rods/drag applications.

Having had no first hand experience, I'm contemplating keeping the 3000k stall in for now and if I don't like it I'll swap it out for the Circle D. That way I'll know why it needs to be changed and gain experience of the difference. It seems like it'd be an easy enough thing to swap on a weekend even after being installed. Unless somebody knows for sure that it's going to be terrible?

What do you guys think?
 

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It's a couple hour job to swap on a V8 CJ. All the bolts are pretty accessible. You only need to move the trans back about 8" to be able to remove the converter or swap a broken flexplate.
 

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Discussion Starter #32
Welp, I'm learning a lot!

It's sounding like even though the LS3 480 dyno charts all look great and very usable for a Jeep, the quality of the low range RPMs is choppy and will cause the tires to lurch, breaking traction, as the engine chops. This problem can be smoothed out with a different torque converter (as I mentioned in a previous post), but that only trades for another set of problems that I worry I'll still be fighting with a custom torque converter like the Circle D. Additionally, from what I understand the 480 needs a higher idle (not good for a Jeep application). The stock LS3 430 will behave exactly like a production LS3, idle at 550rpm, and I can use a lower stall torque converter.

I asked 2 of the main companies that do LS swaps into JKs their experience with the 430 and 480: They said the 480 can be done and has been done and took a long time to figure out a decent tune. The consensus from both was that they prefer the 430 for crawling, cruising, daily driving, and what they'd choose for their own. The 480, they said, is fun for spirited driving.

It feels wasteful leaving 65hp and 50lbft of torque on the table, but I'm starting to think I'd only be trying to tame how wild the hot cam wants to be. If the stock LS3 at 430hp isn't enough once I get it installed, I suppose I can use that as an excuse for a supercharger which would keep the slow speed/low rpm crawling feeling like stock but still let the Jeep eat with a heavy foot.

I'm still doing research to confirm all of this before ordering but I'll probably error on the safe side of knowing what works instead of trying to be the first...
 

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Discussion Starter #33
I hope I'm not exasperating anyone with my research (if so, you might want to check back in 2 months once the major components arrive)! I know this build thread is a much different pace than my main build thread and shares more thoughts, ideas and concerns rather than solutions like my other thread did. The research is so I hopefully can make things work well the first time.

If I had infinite money to try out different engine and transmission combos it'd be fun to try them all and get answers to my concerns and real world data about which combo works best.

Hopefully this thread will still have great solutions to the goals I outlined in my first post!
 

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For what its worth don't go the Tq converter fix, I've ran a 3000rpm converter on trails and it sucks. Deal with the motor-trans as is except get a tuner that knows his shit. He can right files for crawling that will help.
 

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Discussion Starter #35
For what its worth don't go the Tq converter fix, I've ran a 3000rpm converter on trails and it sucks. Deal with the motor-trans as is except get a tuner that knows his shit. He can right files for crawling that will help.
Thanks for sharing your experience on that. It's difficult to trust what I'm finding on the LS1Tech forums since everything is from a pavement perspective.
 

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Discussion Starter #36
I stumbled across something interesting!!! I'm not going to be the first one to tuck the 6L transmission on an LJ! I sent him a message and the transmission pan doesn't hang below the frame either. It's a bit of a relief to see that it tucks nicely and the amount of cutting required appears to be acceptable.







 

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Not sure if they make them for the new LS type engines, (they do for Gen 3 LS's), but the Rhodes lifters might be a solution for the low RPM lope and lower the need for a high idle speed. They bleed off lift and duration at slow rpms, but can't bleed fast enough at higher RPMs so you retain most of your top end power. I've ran them successfully on a few older engines, like the 401 AMC in the CJ and a friend's Pontiac 455. Gained about 6" of vacuum at idle when the oil warmed up on the 401. We could idle the 455 at 550 with a Ram Air 4 cam in it. By about 2500-3000 the cams were all in. These were old school carburetted engines, but I suspect a EFI engine with MAF would compensate fine for them.

Here's a link:

Might be worth a look and a call to see if they would work for you and if they have some for the late LS's.
 
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