V8 Manual Transmission Options

[Shank]

I am in the very early stages of an LS swap (I have a 5.3 on a stand in my garage, step 1 will be tearing into it and seeing what it's condition is). I also like to have plan and know what I'll be working toward/what I need to start acquiring. I am maybe looking at a next winter swap at the soonest. The LJ only sees 1-2,000 miles a year.

The plan is to have reliable, streetable, and fairly economical V8 in my LJ. I am not building for anymore power over the stock 5.3. I am not building for any crazy offroading (yet anyway....).

The options that I seem to have are:

1. NV3500 from a 4.3/4.8/5.3 Silverado/Sierra. This will obviously bolt up perfectly to the engine. I have read one of the best ways to run this with an NP231 is use the front half of a GM case and the back of the Jeep case. Could also built a GM NV3500/Jeep NV3550 hybrid.

2. NV3550 from a TJ. To me this option is probably out. If I were running a 5 speed with an adapter I believe the AX15 is the better option.

3. AX15 from a TJ. Arguably a better transmission than the NV3500/3550 but requires adapting trans to engine.

4. AR5 from a Colorado. Very similar to the AX15.

5. Nissan Frontier 6 speed manual. I somewhat like this idea but the adapter is very expensive then have to figure out the transfer case.

6. TR-4050. Perhaps the best option but I don't know that I want to spend the money on this..

7. NV4500. Very strong transmission but very heavy/large and shifts like a heavy truck (I had a truck with it sitting ready for the swap and decided against it).

8. NSG370. I currently have this but it seems adapters are no longer available.

Any opinions on this?

 

[JKP]

Following to see what you come up with. You can get a brand new AX-15 for about $1600.

 

[Shank]

Following to see what you come up with. You can get a brand new AX-15 for about $1600.

That's certainly a consideration. I'd feel fairly confident with a rebuild NV3500 (which is what I'm leading towards).

 

[Jerry Bransford]

Why not go with the 6L80 six-speed automatic, a very strong beast, which is the usual transmission behind that engine.

 

[pc1p]

If I were considering keeping a manual with my Hemi swap, the TR-4050 (aka Tremec Silver Sport) 5-speed is the only one I would be confident with long term. I've heard nothing but excellent reviews and when I had the chance to chit chat with Trent McGee about it (it sits behind the R2.8 in the IH Scout Ultimate Adventure Rig), he said he absolutely loved it.

 

[Shank]

Why not go with the 6L80 six-speed automatic, a very strong beast, which is the usual transmission behind that engine?

The wife and I really enjoy having a manual vehicle. I am familiar with the 6L80's, her Yukon has one.

If I were considering keeping a manual with my Hemi swap, the TR-4050 (aka Tremec Silver Sport) 5-speed is the only one I would be confident with long term. I've heard nothing but excellent reviews and when I had the chance to chit chat with Trent McGee about it (it sits behind the R2.8 in the IH Scout Ultimate Adventure Rig), he said he absolutely loved it.

It really is likely the go to. I think purely from a strength aspect your options are the NV4500, the TR-4050, and the Nissan transmission. I suppose I need to talk to the wife and decide what our plans for this are. We really enjoy traveling out west but have yet to drive there (and may not have time to drive there for years). Then at what point do you just plan for an Atlas, New axles, etc....

 

[Wildman]

I would get the transmission that will have a cushion of strength so IMO that means it's a NV4500 or TR-4050. Whichever way you choose just don't get one that is marginal. You don't realize sometimes the added strain placed on the transmission when playing off-road.
When I did my V-8 swap I looked at using a NV4500 but due to an injury I needed an automatic transmission so I have a 46RE & STaK's transfer case but I first had a 44RE and burnt up the clutches when I had transfer case issues.

You'll hear a lot of folks who support the NEED for a automatic over a manual transmission but do what you want and enjoy your rig.

 

[Shank]

I would get the transmission that will have a cushion of strength so IMO that means it's a NV4500 or TR-4050. Whichever way you choose just don't get one that is marginal. You don't realize sometimes the added strain placed on the transmission when playing off-road.
When I did my V-8 swap I looked at using a NV4500 but due to an injury I needed an automatic transmission so I have a 46RE & STaK's transfer case but I first had a 44RE and burnt up the clutches when I had transfer case issues.

You'll hear a lot of folks who support the NEED for a automatic over a manual transmission but do what you want and enjoy your rig.

I have my eyes on another 6.0/NV4500 but I don't think I'm going to go that route (though the entire truck is 1/3 the cost of a TR-4050). The NV4500 is very much a truck transmission.

Yes, Auto is better I understand. I don't ever see myself doing any extreme crawling or anything though. The most extreme I would ever likely do is the Alpine Loop which is not very difficult at all.

 

[Gollywomper]

Take a good look at the gear ratios as well. Some heavy duty manual trans have different ratios than what we are used to.

 

[Shank]

A crazy outlier that I could likely pull off...

A custom 4x4 T56/TR6060.

 

[JKP]

https://shiftsst.com/1997-2006-jeep-tj

 

[Gollywomper]

That 6-1 first gear would not be fun on the street. The v8 would probably make the second gear starts work, but not ideal in my mind. Same issue with the nv4500.
The evolution of modern transmissions seems to be skipping the manuals.
I am a manual guy, however I have not found one I would want behind 300hp+ with a decent gear ratio for the street.
Can’t say I have looked at all possible trans though.

 

[Wildman]

I have my eyes on another 6.0/NV4500 but I don't think I'm going to go that route (though the entire truck is 1/3 the cost of a TR-4050). The NV4500 is very much a truck transmission.

Yes, Auto is better I understand. I don't ever see myself doing any extreme crawling or anything though. The most extreme I would ever likely do is the Alpine Loop which is not very difficult at all.

I won't give you grief for going with a LS but it's a running joke for some of us around here.

I have a Dodge 5.9 stroked to a 6.7 in mine. As you and others have pointed out most manual transmission if able to handle the HP/TQ have a crappy 1st gear. I can remember not using 1st when I was a kid and had a truck 4 speed. Unless I was towing or hauling heavy I had a 3 speed. The TR-4050 seems like a better option but it's also tall and the one build I've seen they had to notch the skid plate to make it fit.
If I didn't have my injury I most likely would have stayed with a manual as I like rowing gears.

Good luck with your build.

 

[JKP]

That 6-1 first gear would not be fun on the street. The v8 would probably make the second gear starts work, but not ideal in my mind. Same issue with the nv4500.
The evolution of modern transmissions seems to be skipping the manuals.
I am a manual guy, however I have not found one I would want behind 300hp+ with a decent gear ratio for the street.
Can’t say I have looked at all possible trans though.

I don't use first on the street in my stock Rubi 6 spd unless it's a steep hill. It was great for creeping into the base when the traffic was backed up for ID checks though, haha. Just put it in first and let it idle.

 

[SkylinesSuck]

I'm surprised you didn't have to use 4 low Security Forces weren't usually in the biggest of hurries at Kadena.

 

[Zorba]

SM-420 - if you can get it to fit.

 

[Wildman]

SM-420 - if you can get it to fit.

It'll fit but I think you're missing the POINT. The OP is interested in a modern 5 speed with overdrive type transmission not a boat anchor 4 speed that is really a 3 speed on the street. Yep the crawl factor for the 1st gear is great but he's not trying to run JV.

 

[Zorba]

It'll fit but I think you're missing the POINT. The OP is interested in a modern 5 speed with overdrive type transmission not a boat anchor 4 speed that is really a 3 speed on the street. Yep the crawl factor for the 1st gear is great but he's not trying to run JV.

Add a splitter...

 

[Wildman]

Add a splitter...

After you add 12" to the WB first... But heck anything is possible.

 

[Zorba]

After you add 12" to the WB first... But heck anything is possible.

Naw, you just run the driveshaft out the rear of the Jeep, then chain & sprocket to the diff which you've flipped over. Easy peasy.