4L80e from a TD into a 350 K1500

Hi folks,

I have yet to start sorting out my k1500 Sierra, as I am in Australia things are trickier to here.
My extra cab truck is a 350 sbc with the 4L60e with the NP246 and the 14 bolt semi floating rear diff. Just wondering if the 4L80e and transfer case (np243 I think) from a 99 Suburban 2500 (6.5L turbo diesel) is a relatively straight forward swap?

The Suburban is for sale down the road with a blown engine, I'm thinking of getting it as a parts car for the driveline and the interior. But I have no knowledge at all of the 6.5L TD engine, they barley exist here, so any help would be appreciated.

Yes, it can be swapped into the K1500. Not "too" bad, but requires some modifications.

You need a SBC/4L80e flexplate, rewire the electrical transmission case connector and add the additional speed sensor, repin some wires at the ECU, and ECU reflash, change the input shaft of the transfer case to match the 32 spline of the 4L80e.

I'm assuming this is Vortec-series and it's the '97(?) that can be reflashed with HP Tuners, etc.

I "believe" driveshafts need to be adjusted because one will be too short/one too long. @Supercharged111 has done it to a K1500...mine swap was on a 2WD.

Depending on the year of the donor transmission, may need to adjust fluid cooler lines.

Edit: there may be a difference on the torque converter stall speed difference between the SBC vs diesel.

Sorry for the late reply, I Went off grid for the weekend.

@stutaeng great information there, thanks for that, and yes my existing rig is a 1997 Vortec K1500 with the 350 chev. Just to clarify with the transfer case side of things, is it not possible to use the transfer case from the diesel vehicle in behind the 350? That would mean I wouldnt need to switch out an input shaft, just bolt up the 4L80e and matching TC, then sort out the correct length driveshafts?

I havent looked into the ECU side of things for these too much other then planning out an 0411 PCM swap in the future, not many people local know much about these vehicles so it is a lot harder for me to access those services or even information. I should probably just get the damn thing on the road and ride out the 4L60e until sometime in the future...

The output shafts are different between the 4L60e (27 spline) and the 4L80e (32 spline). So you can't mate a transfer case that was in a 4L60e into a 4L80e and vice versa.

However, since GM did produce the same transfer case behind both transmissions, the solution is to change the input shaft of the transfer case to the larger 32 spline to match your swapped transmission.

Sorry, I just re-read your post and it looks like you you have a matched transmission/transfer case. Then you just have to worry about the driveshaft length issue and the yokes into the transfer case.

stutaeng said:

Sorry, I just re-read your post and it looks like you you have a matched transmission/transfer case. Then you just have to worry about the driveshaft length issue and the yokes into the transfer case.

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Haha, thats cool, yeah that is what I was hoping. Normally I wouldn't be thinking about this sort of thing at this stage, but with only 800 odd Suburbans in the country when one pops up for sale 30 minutes away you start thinking real hard about how best to make use of it. Knowing that the 4L80e and TC from the 6.5L TD hooks up with minimal fuss really gives me food for thought. Thanks again @stutaeng

Yes the Holden Suburban was only available from 1998-2001, they're all 400 series. K1500 was 5.7 gas, K2500 was 6.5 TD. Less than 900 built of both models; they were rather expensive.... This information was obtained from other Aussie and Kiwi members.

If the suburban is in decent shape, seems ideal for a Holden V8 swap since I am sure those a super common.

L31MaxExpress said:

If the suburban is in decent shape, seems ideal for a Holden V8 swap since I am sure those a super common.

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You are probably right, but I tell ya... Adding another project to the list of stuff I have to do would probably end me! I wanted the Sierra on the road by now and I have barely touched it. I'm getting there though