5.3 drivetrain vs. 401/700R4 swap

[srobertsfsj]

So I am starting to prepare for the next phase of my upgrades and I know for sure that I want to go to an OD tranny and a fuel injected motor. After reading all the different posts both here and on IFSJA regarding the different things you guys are doing I think I have narrowed it down to just doing an entire 5.3 swap or building my 401 with FI and sticking a 700r4 behind it. I like the idea of going with an AMC engine because I love 401's and I like to stay true to the names but I am realistic as well. I want reliability and driveability so I can do both on-road and off-road driving. I would like to get everyones thoughts on which would have the path of least resistance. I understand these are both not drop in solutions and will have do fabwork.

What modifications are needed for each scenario? How are you guys doing the shifting? I would think that either tranny would not mate up to a stock column shifter. Is one swap significantly cheaper than the other? Any insight is helpful.

Thanks!

[babywag]

I'd go with the 5.3/6.0 LSx and a 4L80E

Soon as I get an engine that's what will be going in my '88.
I'll have a set of motor mounts coming from JeepinPete once he makes his next batch.
Already have the 4L80E/NV242.

I really wanted to build a multiport injection system for my AMC, but the costs just didn't make sense when I added it all up.
Couple that with the cost of adapting the 4L80E to the AMC, that money could easily be better spent staying with the LSx stuff.

I'd love to have a MP 401+4L80E, but it's actually cheaper(for me) to go with a used 5.3/4L80E.

[Road Trip]

I've found several good threads on here about swapping to the GM drive train. I'm going with the 5.3L and the 4L60 tranny from a 2003 - 2007 vehicle. They are looking for it now. I've got the motor mounts from JeepnPete and I'll be using Wayne Hartwig for the programming, I got his name from CAPTSmith.

I have chosen to upgrade to something that has power, economy and durability, oh and any shop in town can work on it. Nothing wrong with the other way, just the way I'm going. My $.02.

[srobertsfsj]

Good info so far. How do you both plan on handling the shifting for the tranny and the TC?

[babywag]

The 4L80E would be controlled by the LSx PCM, and the NV242 is a manual shift TC, so just need to fab up a shift rod.

If I was to stay w/ my current setup, the computer I have running the TBI could easily shift the 4L80E too.
It's the 16197427 GM computer, and also capable of MPFI.
Could do a 4L60E as well.

There are also $$ aftermarket standalone systems for just the 4L80E.
For the money not worth it IMHO when you could do it w/ a junkyard system MUCH cheaper.
GM diesels also used a standalone system for the 4L80E, I have one of those too.

[FSJ Guy]

Scott, you're already set up for an EASY swap to the 16197427 PCM. The biggest issue you'd run into is adding the transmission wiring. And that's an easy 12 wires or so and the transmission connector.

The 5.3L swaps are VERY enticing, but I'm with you, I'd like to stick with the AMC motors until they become so rare that people will GIVE me a 6.0L and a 4L80E for my 401.

[srobertsfsj]

The 4L80E would be controlled by the LSx PCM, and the NV242 is a manual shift TC, so just need to fab up a shift rod.

I should have clarified that by shifting I meant shifting from park to drive, neutral, etc. Is there a good aftermarket solution for this?

[FSJ Guy]

I think you can use the stock column. You might have to repaint the PNRD321 numbers, however. Or use an aftermarket floor mounted shifter.

[Austin4x4]

Hey Scott, i am just finishing my 5.3, 4l60e, np241c swap in my truck. Lokar makes a kit that works with the stock steering column and 4l60e, which is what i used. but with a little time it woudn't be to hard to make your own. for the transfer case i am just going to use a stock shifter from a chevy pickup that came with a 241c, haven't installed the TC yet but everything looks like it will fit just fine.

[jamesdart]

im doing the 700r4 swap right now. for a split second i thought i might as well go for an ls swap while im at it, wont cost much more. then i slapped myself, im more than familiar how engine swaps will nickle and dime you to death. id like to do the tbi on my 360, but i also happen to have a fast ez efi sitting on my shelf i bought for my car and decided to do something else.

[srobertsfsj]

James, do you have a build thread going?


I have another question regarding both swaps. Can the stock crossmember be used or does a new one need to be fabricated?

[srobertsfsj]

Also, how does the kickdown work on the 700R4? Is it mechanical like the 727?

[AwesomeJ10]

I made a new crossmember in the J20 out of 1.75" tube.

The detent cable on a 700r4 is very sensitive. You will need to adjust the cable prior to running the trans. There are some electrical connections to lock the TC. Lots of info online. I wired mine into a simple led switch (the kinda switch that comes with cheapy bumper lights). It lights up when the TC is locked and if I flip the switch it manually locks the TC. Some people wire the switch into a vacuum switch so that it unlocks when it drops to a certain vacuum level. My manual switch works fine and I could create a schematic if you need. Wasn't hard to find.

[Blazer3664]

700R4 has a TV (throttle valve) cable that controls kickdown and line pressure as well.


edit = I see Blake responded while I was one finger pecking an answer, he covered it pretty well.

Jim

[jamesdart]

i have a build thread but i didnt update it for the trans yet. it looks like the stock crossmember will work with a 2" spacer, i think. i will have it back in today. i need to get a measurement from someone where the rear output should be, like from the bottom of the frame rails up to center of output. i went with an 88 700r4, and dana 300. i used an AA engine to trans adapter, a stock gm adapter and jb conversion input shaft. sealed input bearing off ebay. the 300 is almost flat with that setup. there is no room for the double cardan. i think if i was to clock it down the driveshaft would get closer to the pan rail. its looked way to close already. it would have been nice to put a 231 between the 700 and 300 but this current upgrade is costing way more than i was hoping to ever put into my beater.

[ProTouring442]

I will echo the posts on the TV cable. It must be adjusted properly, and it must pull at the proper ratio to the throttle cable, or you will burn up the transmission.

[CAPTSmith]

Just finished my 6.0 LS Vortec, 4l80e tranny with Lokar 16" floor shifter, np241c TC and love it! Used Jeepinpete motor mounts, but hear BJs have good ones also. Major fab work was with tranny cross-member, efi fuel tank, driveshaft mods, fuel lines, and tranny and oil lines. Used Wayne Hartwig for the wiring and he did an excellent job in thinning the engine harness wires, labeling them, flashing the PCM, and answering my many crazy questions! The dependability, power, torque, fuel economy is outstanding ! I truly understand the importance of staying original and did so with my built 360 ci in my '74 Javelin AMX, but with the jeep I am so happy with the swap and was much easier than I thought it would be! Best of luck and if I can be of any help let me know.

[supergeess]

Just finished my 6.0 LS Vortec, 4l80e tranny with Lokar 16" floor shifter, np241c TC and love it! Used Jeepinpete motor mounts, but hear BJs have good ones also. Major fab work was with tranny cross-member, efi fuel tank, driveshaft mods, fuel lines, and tranny and oil lines. Used Wayne Hartwig for the wiring and he did an excellent job in thinning the engine harness wires, labeling them, flashing the PCM, and answering my many crazy questions! The dependability, power, torque, fuel economy is outstanding ! I truly understand the importance of staying original and did so with my built 360 ci in my '74 Javelin AMX, but with the jeep I am so happy with the swap and was much easier than I thought it would be! Best of luck and if I can be of any help let me know.

I too just completed a 6.0/ 4L60E/ NP241 swap with Slip yoke eliminator, GM EFI tank, hydroboost (Elliott), electric fan. Unfortunately, I am not great at taking pics along the way, so I have no build thread or detailed pics. But I can tell you that everything that CAPT says is true. Once you get going, it is a pretty easy install. Once you have your engine mounts (Searchers 4WD...I think), the engine and trans drop right in. I did modify my cross member, but later realized that I did not need to if I had just moved it forward to the most forward holes in the frame. But...if I did that then I would not have been able to route my exhaust as easily since I reatined the cats. I had my harness reworked and PCM programmed by Wait4ME. They are excellent and very helpful and responsive. Had my rear driveshaft shortened, replaced front driveshaft (stock was too short). Might not have needed to do this either if i used the other holes for the cross member. But you live and learn. The power, fuel economy, idle, reliability and clean exhaust smell compared to the old carbd engine is amazing. You cannot go wrong with this swap. If you have any questions, you can PM me. But, with most things, it is the small things that are the biggest pain. In retrospect, I did not have any major issues with the "small stuff", but the small stuff is what takes up your time. Next...gauges, paint, then more small stuff.

[srobertsfsj]

Hmmmm, that sounds like a good route to go, I am going to have to look into that. So stupid question, how does one find a complete drivetrain and how much would I expect to pay for one? Wrecking yard? I would think that if it was at a wrecking yard then there would be damage or the engine/tranny is bad. What years, make and models do you look for?

[supergeess]

I got my 2005 engine/ trans combo with harness, ECM, DBW pedals and anything else I needed in October 2011 for $2700 at a local salvage yard delivered to my house. I actually went down and started the engine and drove the wrecked Denali a few feet forward and back prior to purchase. A reputable yard won't sell you something that's broken. By now you can get better pricing. My 6.0 is a LOT of power. You will be very happy with a 5.3 and you can get much cheaper and easier to find.