1988 Suburban LS Swap - Part 3 - 6L90E Disassembly/Mating NP208 to 6L90E

[@JustJeep_It]

Finally...someone posted a great video of the teardown. Man you have a TON of knowledge....you made a subscriber out of me!

[@MrJTime]

This is THE video I’ve been waiting for. Thanks for posting.

[@RogueKnight33]

This is a great video find! Got one from the junkyard with low miles and want to do this as well

[@JEGsGarage]

Hi Matt! It was pretty easy to work on! Surprisingly easy considering its "newer technology".

[@kevinsahr1048]

I'm doing basically the same swap only difference is ly6 6L90 Np241 s480 turbo in a square body I sent my output shaft to Moser to be machined

[@FormulaBoat]

Hi buddy. I'm getting ready to do nearly the same marriage, but instead with a 6L80 or 90 and a NP241C transfer case (pass drop as well), for my V8 Colorado. Was there not a 29 spline input gear available for the t-case you used? Guessing no. It so far looks like there is for the NP241C I am using (for Dodge), I just need to see if the Dodge and GM 29 spline is the same dimensions. 29 spline if I use the 6L80. 32 spline is I use the 6L80. Stock trans in truck is 4L60e, of which a few have swapped the 6L80 which is nearly the same length. I have to see if I can go with the longer 6L90, 1.5" or so. Thanks for posting.

[@bdavis12758]

how's the progress on your swap? awesome and detailed videos. Did you get the output shaft machined?

[@sddnhad]

How much did you cut off the 2wd output shaft? I've read 3.75" Can you verify that?

[@holdenc3082]

@@JEGsGarage I’m curious what you did for a gear shift indicator? I’m trying to get this worked out right now with a 6L90E going into a 91 square body Suburban. My stock trans was a 700R4 so I’ve got to figure something out for a shift indicator since the old mechanical indicator won’t work. I have a Dakota Digital dash and they have some sort of module that works with their dash supposedly. I need to give them a call because their description is confusing about how it works. Is the shift pattern PRNDL On the 6L90E?

[@holdenc3082]

Also need to figure out how to get the tow/haul mode to work since I’ve got no way to control all that with no touch screen or button on the shifter. Lots of stuff to work out getting one of these transmissions to work in a square body.

[@JEGsGarage]

@@holdenc3082 my factory 700r4 shift indicator works pretty decent. Though I think I hardly ever look at it. I just move the shifter as muscle memory pretty much. The Dakota digital cluster SUPPOSEDLY shows correct gear with the module, however I've yet to see an example of it working or confirmation. Tow/haul and tap shift are a little more involved. I think tap shift is just building a button with the correct resistances, there are write ups online. Then some tuning to get it working.

[@holdenc3082]

@@JEGsGarage Hey man thanks for the reply. I’d prefer to just keep an old school mechanical shift indicator if we can get it to work respectably with the 6L90E shift linkage. The truck the engine came out of has a tow/haul button on the dash so that’s just a switch to add to my Suburban and shouldn’t be a big deal. The tap shift up and down might be a little tougher to work out. Next up got to figure out cruise control. Would be great if we can get the old factory square body stalk to work. Any issues getting the 6L90E to fit in your Suburban? I’ve heard the trans tunnel may need some cutting.

[@JEGsGarage]

@@holdenc3082 the shift indicator should work ok enough. Once you get down below OD it starts to start a bit. The tow haul button may go through the body control module though. If it goes straight to the ECM or Trans, you're set! Cruise is difficult. Again, it's BCM controlled. Check out RPM Extreme. They have a module but it's $$$, at least they used to. Makes it work like factory though. I used their AC module so my AC works like factory vs using pressure switches all over. NO issues with fitment for me. Tejas motor mounts put my 6L right at the factory trans crossmember. Used a factory Tahoe mount, and even modified my transfer case brace. I have more videos coming! I'm over a year behind in posting 🙄

[@fcovial1]

Where your machined the output shaft? you can give me details?

[@JEGsGarage]

Contact Moser Engineering. They'll hook you up. You need to send the trans output shaft to them for machining. If you have specific questions let me know!

[@SyTySpeedShop]

@@JEGsGarage care to share the cost to get it machined?

[@FormulaBoat]

@@SyTySpeedShop Moser charges about $85 to turn down and re-spline a single shaft.