Manual Trans LS Swap Questions

[KI4UJO]

I have a 1990 K1500. It currently has a SM465. I'm planning on dropping in a 5.3 out of a 99 Silverado to replace the current carbed mild-built sbc.

I'm looking to swap the SM465 for a box w/overdrive, probably a NV4500 or something similar (have considered an NV3500, but not too sure on how robust they actually are + LS compatibility). What am I going to need to do as far as bellhousing, clutch, flywheel,etc? It's also worth asking - if I kept the 465, what is involved?

Sorry if I'm asking something that has been covered elsewhere, I searched and didnt come up w/much. I've done some C3 Vette stuff but 98% of my background is in BMW.

Thanks in advance!

 

[DerekTheGreat]

I am not an expert and hopefully someone else with definitive knowledge will post but what I can tell you is that a NV3500 will pretty much grenade if more than 300ft-lbs are fed to it. Also, the NV4500 is a damn near direct swap for a dump truck SM465. I believe Chewy1576(?) swapped his 465 for one and was able to use the existing crossmember/mount and driveshaft as well as the flywheel and clutch. Now of course this was all behind the traditional SBC. Interior wise you just need the different trim piece I believe. In 1995 or 1996 or so they modified the NV4500 to use an internal slave, so if you want to use a 4500 from 95 and up you'll need to do some modification there.

Although if going to an LS I'm sure another question that'll be asked is why NV4500? The later ones also ended up with a 1st gear that wasn't as steep or considered a granny but they still aren't quick shifting units so you might be better off with a T56 or something.

 

[brianmcb]

Nv3500 has held up for almost 4 years behind my cammed 5.3...and I get on it often. I wouldn't clutch drop it with slicks though

95 rcsb, L33 5.3, hot cam, frost tune, 5spd, 4/6

 

[KI4UJO]

Considering the NV4500 for the overdrive gear. My goal is to use the existing transfer case - not sure how a T56 would fit into that picture (If it was 2wd, I'd definitely go that route). Any other trans recommendations that would work with the TCase and LS? TBH I have the auto from the Silverado which has no issues (Truck went over a guardrail due to ice) but I really don't want to go the auto route (Not sure if its a 4L60 or 4L80, haven't crawled under it yet to look).

 

[skylark]

T56 is a no go for a 4wd. I saw an extremely expensive adapter a longtime ago. A nv3500 will hold as long as you aren't going nuts in a 2wd with small tires but 300+ torque and tall tires and it may as well be wearing a diaper for when it craps itself. You can do either a 3500 or a 4500 behind an ls using a sachs 1050 flywheel and a sbc clutch. If you did decide to go auto, be careful of the transfer case spline count. 8f I recall correctly the 4l60e has 27 spline and the 4l80e/stick shift have 32 spline. Also keep in mind that only 5 bell housing bolts line up when using a gen I patterned bell housing with a gen 3 engine.

 

[Sparkysikes]

4wd and granny is a great combo. The 4500.is a slow rower but a stout transmission. The 2 to 3 ratio is a bit asckewed if towing with a low revving diesel but otherwise is great. I loved mine but many clutch/ slave failure issues and the fact my rig is always heave and going up steep hills I swapped to auto. Turns out my clutch pedal was the issue! Bad pivot. The external slave isn't as robust but hella easy to work on. Bleeding is difficult and requires 2 people. Blah blah.

Good luck

 

[Spookers]

A buddy of mine has a reg cab short box that started life with a 4.8 nv3500 2wd, which then got a Whipple then a cammed and blown 6.0 and now just a calmed 6.0 and only ever was driven with the foot on the floor, he went through a 4.8 and is on his 2nd 6.0 and 3 axles and a drive shaft, still the original nv3500, it does have a little tail stoke play so it may be out the door soon but needless to say it took a lot to get it there

 

[skylark]

A buddy of mine has a reg cab short box that started life with a 4.8 nv3500 2wd, which then got a Whipple then a cammed and blown 6.0 and now just a calmed 6.0 and only ever was driven with the foot on the floor, he went through a 4.8 and is on his 2nd 6.0 and 3 axles and a drive shaft, still the original nv3500, it does have a little tail stoke play so it may be out the door soon but needless to say it took a lot to get it there

Add heavier tires and more weight and it most likely would be eating trannies too.

 

[Spookers]

Add heavier tires and more weight and it most likely would be eating trannies too.

He's had drag radials on it and 1/4d it a few times so it can handle hard launches

 

[DerekTheGreat]

...There's always that "one guy"...