New project ideas, anyone work with a 6L80E?

[derf]

So I'm not sure if this is the best place to ask this question or not.  If there is a better place, please move this post.


I'm working on starting the plans for a build.  I'm keeping the engine choice to myself for now.  But I will be hooking up to a computer controlled automatic transmission.  Every engine would require an adapter of one kind or another so picking on specific transmission  doesn't have much of an impact on that.

I've done several engine swaps on different vehicles so I'm familiar with the fabrication I'll need to be doing.  I've seen the IFS front mounting bracket in place on the Eagle and I'm formulating a plan to manage that, assuming I don't swap in a solid axle.  I'll probably be grabbing an XJ rear axle (D44 or 8.25 depending on what I find) but that's pretty easy to manage.  It's really just leaf spring perches and shock mounts, along with a custom length driveshaft.

The transmission will be connected to an NP229 transfer case from a full size (Grand) Wagoneer.  I'll grab a flag shifter as well to manage the low range and keep the vacuum knob on the dash in the Eagle.

But really, the swap centers around the transmission choice so I want to get that settled earlier rather than later.

My leading contenders are:

AW4 from an XJ.  This issue is less than ideal for several reasons and I'm not going to put much effort into researching it.  Even if it were given to me for free.

4L60E.  This transmission is easy to adapt to the FSJ transfer case as well as my chosen engine.  I have seen several threads where people have swapped this into an Eagle so I know it will fit.  This is my "backup" choice.  I know it fits. I know it can be adapted to the other parts.  I know it has a nice wide gear range with a deep overdrive.  And I've worked out the axle gear ratios I'll need with the tires I want to run so that it will run in the proper RPM range.  This one is the "safe" choice.

6L80E.  This is the one I'd really like to go with.  It has a deeper first gear and a slightly taller final overdrive, giving me a much broader gear spread for various situations.  I know it can be adapted to the other parts without too much fuss.  I know the axle ratios I'll need to run with the tires I want.  I've even found a floor shifter that will work with its computer and I can fabricate that in place of the factory shifter.  What I don't know is whether it will fit inside the transmission tunnel without modification.

Looking around, I've found out that the body of the transmission is wider than the 4L60 by maybe a couple of inches.  It might be as wide as a 4L80E.  The length is close to the 4L60.  So it should fit front to back nearly the same.  But it's the width that I'd like to talk about.

Has anyone tried to fit a 4L80 in an Eagle?  How much space did you have around it in the tunnel?

For those who have installed a 4L60 or 700R4, what kind of room did you have around the transmission when it was installed?  Would a transmission with 1-2" of extra girth fit in there without modification?

Thanks for any advice or experience you can share with me.   

[eaglefreek]

From my recollection, there wasn't much room left with the 4L60E installed. If you don't mind me asking, why a 229? Also, why not an AW4/242 combo? Since you are looking at using a transmission even beefier than a 4L60E, I assume it's either a high torque gas engine or possibly a diesel.

[derf]

From my recollection, there wasn't much room left with the 4L60E installed. If you don't mind me asking, why a 229? Also, why not an AW4/242 combo? Since you are looking at using a transmission even beefier than a 4L60E, I assume it's either a high torque gas engine or possibly a diesel.

Thanks for the info on the transmission.

A 229 would work with the existing vacuum shifter in the Eagle.  And the flag shifter from the Wagoneer would be an easy cut and bolt-in.  A 242 would certainly be an option.  The shifter installation is more complicated though.  Since I have my Jeep for off roading, the lack of a 4HI lock option isn't that big of a deal to me.  I could even stick with the 129 that comes in the Eagle because I don't absolutely need low range.  It's more of an "as long as I'm doing the swap..." kind of thinking.  The plans are still just in my head mostly so no final decision has been made yet.

The only reason for the 6L80 is the wider span of gear ratios.  4.03 first gear to 0.67 overdrive gives me the ability to run shorter gears (up towards 3.54 or 3.73) without losing freeway mileage, and that is easier than trying to make 2.73's or 2.35's work.  At a minimum, 3.08's would work and those are actually available from what I can see.  The 4L60 goes from 3.06 to 0.70 which is still a respectable span and probably still be more than fine.  I don't need the strength so much.  The engine I'm looking at is under 300 ft-lbs.  But it's the wide aftermarket support of the computer controlled transmissions that make those the go-to options.  It's also why I haven't 100% ruled out the AW4.  Again, not huge torque but I need the computer control.

Edit:  Though now that I think about it, the 6L50 looks like it would also be a viable option, and smaller than the 80.  Though it's mostly found in 2WD applications and there aren't a lot of adapters out there on the market.

Thanks again for the info.

[eaglefreek]

If you decide to go the route of an AW4, I have a TCU and part of a harness that I already labeled the wires. It just needs to see same TPS voltage that a 4.0l TPS sends to the TCU. Also, if you care to share what engine, there maybe a bellhousing option for the AW4. I've got the Aisin A340H (practically all identical to the AW4) in my 88 Trooper and I'm considering a Lexus 1UZFE 4.0L. The Lexus auto bell housing will bolt up to my transmission. Not trying to convince you to do something you don't want to, I just like discussing Frankenstein combos.

[derf]

If you decide to go the route of an AW4, I have a TCU and part of a harness that I already labeled the wires. It just needs to see same TPS voltage that a 4.0l TPS sends to the TCU. Also, if you care to share what engine, there maybe a bellhousing option for the AW4. I've got the Aisin A340H (practically all identical to the AW4) in my 88 Trooper and I'm considering a Lexus 1UZFE 4.0L. The Lexus auto bell housing will bolt up to my transmission. Not trying to convince you to do something you don't want to, I just like discussing Frankenstein combos.

Advance Adapters has me covered for the AMC bolt pattern.  So that's why I say the AW4 is an option.  I just like the deeper overdrive of the GM alternatives.  And the strength + heat generation characteristics are better, not to mention the rest of the aftermarket support.

One issue I have to look into is the starter.  I need to do some studying because it's on the same side as the differential.  So the bracket to the engine block becomes a "how do I do this" or do I just punt and grab the front D30 from the same XJ I plan on getting the rear 8.25 from and do a solid axle swap?

Or do I punt entirely and just do this swap in an XJ or MJ?

What can I say, I like a challenge.