LS swap with manual trans

[Tomo]

I’m planning my first ls swap and need some advice. The project is my 70 k5 and my main requirement is that it has to have a manual trans. Since this is my first swap my goal is to buy an entire truck and swap everything over so I don’t end up piecing everything together. My first thought was to find a 6.0 5 speed (nv4500) donor truck but from what I’ve seen those are pretty rare. My question is has anyone done a 4.8/nv3500 swap? And are the nv3500s as weak as most people online say they are?

[mongocanfly]

I put a nv4500 behind my 6.0....I used all advance adapter parts to do it...not cheap but I love it...about the same cost as a 4l80....fixing to do another one in the near future...yours being 4x4 you'd need a 4wd version or use a divorced transfer case...wouldn't waste my time with a 3500 behind a ls...
you really don't have to have a whole truck but its nice if you can find one...

[scoot_mcgrute]

I have an S10 T5 holding up behind my 5.3 and it outlasted the 12 bolt. I don't baby the truck, it has 275s with a 200 treadwear rating and I autocross it as well as drive it a lot during the summer. I'd run an NV3500 behind a 4.8 any day.

[Tomo]

After seeing an Icon 4x4 video on YouTube I went to their site for more info. They build some awesome vehicles. They use an ax-15 behind an LS3 in their FJ builds.

https://www.icon4x4.com/specifications/index/fj

Anyone have any experience with this trans? If it can handle the LS3 it shouldn’t have any issue with a stock 5.3. I know this leaves me to piece the swap together but it seems like the nv4500 might be too much for the cruiser I’m building.

[BR3W CITY]

^^Isn't that a pretty standard 90's Jeep trans? It handles the 4.0 I6, but not sure if its actually holding an LS3 in stock form. They've gotta be using a modded/upgraded unit if I had to guess. There are a number of LSx jeeps, so maybe poking around their hangouts might shed some light on whats being used.

[Tomo]

Originally Posted by BR3W CITY

^^Isn't that a pretty standard 90's Jeep trans? It handles the 4.0 I6, but not sure if its actually holding an LS3 in stock form. They've gotta be using a modded/upgraded unit if I had to guess. There are a number of LSx jeeps, so maybe poking around their hangouts might shed some light on whats being used.

That was my thought exactly. The price tag on those FJs makes me believe that their version of the trans can handle it.

I sent icon an email asking about the trans. Not sure I’ll hear back but if I do I’ll post the response.

[Tork?]

Had a nv3500 in an 02 4.3 Blazer I used to beat on that thing power shifts and burnouts didn't miss a beat traded it in with over 100k miles shifted fine

[russgt]

I had a 3500 behind a 4.3 in a 04 xtreme blazer. Good trans but it did not like to shift into 3rd at wot. Hurst makes a competition plus for it, that helped it tremendously.

[steven03]

In my '65 long bed i had a bolt on 350 with a cam and an s10 t5 trans behind it. On junk 275s and an open rear end I blew apart the input shaft on the s10 t5 during a 1-2 shift. Rolled into it in 1st and grabbed 2nd, foot came off the clutch pedal and that was all she wrote lol. That engine i assume made way less than what even an almost stock ls would put down.

[Tomo]

Originally Posted by Tomo

That was my thought exactly. The price tag on those FJs makes me believe that their version of the trans can handle it.

I sent icon an email asking about the trans. Not sure I’ll hear back but if I do I’ll post the response.

Jonathan Ward sent me this reply:

“The AX15 is a great transmission, and the engineers there have assured me it is underrated. Never had an issue nor warranty claim on them. Thanks, JW”

[Tomo]

My project is moving slow (not moving at all if I’m being honest with myself!). But I’m still going back and forth on the swap. Stuck...4.8 & nv3500 seems small and delicate but 6.0 and nv4500 seems like overkill in my k5. Any words of wisdom from someone with experience with the 1999+ new venture transmissions?

2 things I’m 100% on:
#1 my blazer will have an ls style engine & manual trans
#2 my preference is to buy a complete donor truck for all the parts (ax-15 is out)

[Tork?]

Camaro Tr6060 will hold up and with a $200 shifter relocation it pops out in the middle of the floor hump. Will require joint adapter too. Trans are $2k or less.

[mongocanfly]

Tork....Cant bolt a transfer case to a tr6060.....and that's a long trans..so even if he went divorced it would be way back in a k5...resulting in steep ds angles in the short blazer

Although not cheap a nv4500 is one of the best options...check out old57 build in the 47-59 build section...he just upgraded from a sm465 to nv4500...I promise you..a nv4500 is not overkill

[Tork?]

Ah yeah didn’t see it was 4wd

[LockDoc]

Originally Posted by Tomo

After seeing an Icon 4x4 video on YouTube I went to their site for more info. They build some awesome vehicles. They use an ax-15 behind an LS3 in their FJ builds.

https://www.icon4x4.com/specifications/index/fj

Anyone have any experience with this trans? If it can handle the LS3 it shouldn’t have any issue with a stock 5.3. I know this leaves me to piece the swap together but it seems like the nv4500 might be too much for the cruiser I’m building.

I have a '91 Jeep AX-15 behind a stroked 377 Chevy engine in my '34 Ford Coupe. I have only driven it up and down the driveway but I did a lot of reading on them before choosing one for the car. I have no doubt it will hold up to my engine.... The Toyota Supra Turbo R154 is the same transmission.

I also put an NV4500 in my '72 Chevy Dually and it is a great transmission. Shifts good, cruises down the interstate at 75 easily. and will pull a stump if you need to.

LockDoc

[cebra]

I am currently working on that exact setup 4.8L and NV3500. Be careful what motor and trans you get as the 4.8 manual motor in 99-00 is different and from my search, really difficult to find. I went with a 4.8 auto motor and put in a wider (nfw1050) flywheel to mate to the NV3500. I had to pay a ton of money for a NV3500 and drive over 6 hours to find one btw but you may have better luck. My brother in law had a 4.8/NV3500 Silverado he beat on for 160K miles and had no trans issues.

[Tomo]

Originally Posted by cebra

I am currently working on that exact setup 4.8L and NV3500. Be careful what motor and trans you get as the 4.8 manual motor in 99-00 is different and from my search, really difficult to find. I went with a 4.8 auto motor and put in a wider (nfw1050) flywheel to mate to the NV3500. I had to pay a ton of money for a NV3500 and drive over 6 hours to find one btw but you may have better luck. My brother in law had a 4.8/NV3500 Silverado he beat on for 160K miles and had no trans issues.

Thanks for the info.

The other reason I’m torn is the 1/2 ton trucks seem to be more plentiful around here. There’s a 1999 4x4 4.8/nv3500 gmc on Craigslist right now for $2500 - running and driving. The 3/4 ton (6.0/nv4500) trucks seem to be more rare and they ask a premium for them. Just don’t want to regret the decision down the road!

[Pontitruck]

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