• RME Gear & Apparel

Its Time... Manual -> Auto Swap

TJustin

TJustin

Wonton Wannabe
Supporting Member
Location
Payson, UT
tl;dr- Looking at auto swapping my NV3550 to an auto trans. I'd like feedback and experiences. :cool:

Long story short, I've had my TJ since late 2008, and have wheeled with the stock NV3550, originally with the NP231, then a TeraLow 231HD, then 4.3 Atlas, and now currently a 5.0 Atlas. On my most recent trip to SH this weekend while on Twister and some side obstacles on Unforgiven and the Maze where I have seemingly found the limitations to the 5-speed, especially when it is slow and technical, and managing 3 pedals got to be quite the nuisance. One of the bonus lines on The Maze stands out where I pushed in the clutch completely mid-obstacle, unloaded the drivetrain and subsequently slid off my line. The rig shifted, falling ~3-4 vertical feet. I'll attach a video in a following post.

Fast forward to now, where I am looking at swapping in an auto trans. I haven't wheeled one for almost 20 years and at that point I was green-at-wheeling teenager, and even since then I haven't dug too deep into autos since the lower t-cases solved my apparent problems til now. I am open to feedback or considerations as I work through this process.

I want simplicity, and relatively straightforward install. While a trans with OD would be nice, it's definitely not necessary as its trailered and hasn't seen a freeway in years. I'm leaning towards a 32RH from a similar model year of TJ. It appears to be more or less R&R, and maybe an ECM flash for torque converter lockup. Open to options this point from those who know more than myself.

I am looking for feedback and considerations to keep in mind as I start to identify a game plan.

  • I understand TH350/400/700R4 are options, but not terribly interested at this point due to the added complexity with assumed adapter plates . Unless there is serious flaws with the 32RH, these don't seem worth the hassle behind a bone stock 4.0.
  • AW4 is not ideal because wiring needed for it to work and added drivetrain length.
  • Will I be hating life if I have a 5.0 Atlas behind any auto?
  • Any benefit from a custom converter?
  • Manual valve body? Reverse manual valve body?
  • Other things I need to keep in mind?
 
Hickey

Hickey

Burn-barrel enthusiast
Supporting Member
Location
Grantsville, Utah
TJustin said:
tl;dr- Looking at auto swapping my NV3550 to an auto trans. I'd like feedback and experiences. :cool:

Long story short, I've had my TJ since late 2008, and have wheeled with the stock NV3550, originally with the NP231, then a TeraLow 231HD, then 4.3 Atlas, and now currently a 5.0 Atlas. On my most recent trip to SH this weekend while on Twister and some side obstacles on Unforgiven and the Maze where I have seemingly found the limitations to the 5-speed, especially when it is slow and technical, and managing 3 pedals got to be quite the nuisance. One of the bonus lines on The Maze stands out where I pushed in the clutch completely mid-obstacle, unloaded the drivetrain and subsequently slid off my line. The rig shifted, falling ~3-4 vertical feet. I'll attach a video in a following post.

Fast forward to now, where I am looking at swapping in an auto trans. I haven't wheeled one for almost 20 years and at that point I was green-at-wheeling teenager, and even since then I haven't dug too deep into autos since the lower t-cases solved my apparent problems til now. I am open to feedback or considerations as I work through this process.

I want simplicity, and relatively straightforward install. While a trans with OD would be nice, it's definitely not necessary as its trailered and hasn't seen a freeway in years. I'm leaning towards a 32RH from a similar model year of TJ. It appears to be more or less R&R, and maybe an ECM flash for torque converter lockup. Open to options this point from those who know more than myself.

I am looking for feedback and considerations to keep in mind as I start to identify a game plan.

  • I understand TH350/400/700R4 are options, but not terribly interested at this point due to the added complexity with assumed adapter plates . Unless there is serious flaws with the 32RH, these don't seem worth the hassle behind a bone stock 4.0.
  • AW4 is not ideal because wiring needed for it to work and added drivetrain length.
  • Will I be hating life if I have a 5.0 Atlas behind any auto?
  • Any benefit from a custom converter?
  • Manual valve body? Reverse manual valve body?
  • Other things I need to keep in mind?
Click to expand...


The 5.0 Atlas will lessen the need for the AW4 and its lower 1st gear. Any custom changes to whichever trans you pick will be much cheaper if you pick the TH350.

If you decide to go TH350, I know where you can source the necessary adapters to fit your application. A friend has a used set.
 
1969honda

1969honda

Well-Known Member
Supporting Member
Location
Cache
Converter will also make a big difference in several areas. Someone more experienced than me with your drivetrain setup I'm sure will chime in with a good stall speed to look for.
 
N-Smooth

N-Smooth

Smooth Gang Founding Member
Location
UT
I’d think AW4 would be the answer but if not, a 32RH would be cool. That’s just a 999 with electronic lock-up, right?
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
I'd say use a trans that doesn't require adapters, has OD and hopefully a lower 1st gear. I don't think the 5.0 Atlas will cause and issues with being too low, you'll just have more control in those super technical situations... and you can always use 2nd gear if you need more wheel speed.

You'll want a higher stall convertor so it doesn't crawl thru the brakes in low range... I'd say 2200 - 2400 RPM. A higher stall convertor will create more heat, so a proper trans cooler is needed to keep the trans happy.
 
B

bobdog

4x4 Addict!
Location
Sandy
What is the budget? My first choice would be an AMC TH-400. Reverse manual valve body. You say no OD needed and I see no downside to as much strength reliability and simplicity as you can have. 5.0 to 1 Transfer case makes the ratio all you will ever want. Is driveline length an issue?
 
TJustin

TJustin

Wonton Wannabe
Supporting Member
Location
Payson, UT
N-Smooth said:
I’d think AW4 would be the answer but if not, a 32RH would be cool. That’s just a 999 with electronic lock-up, right?
Click to expand...
To my understanding, yes.

bobdog said:
What is the budget? My first choice would be an AMC TH-400. Reverse manual valve body. You say no OD needed and I see no downside to as much strength reliability and simplicity as you can have. 5.0 to 1 Transfer case makes the ratio all you will ever want. Is driveline length an issue?
Click to expand...
TBH, I haven't got that far regarding budget. Just started looking at options. Driveline length is something to keep in mind, but I should be able to absorb a slightly longer trans with little issue.

Johnny Quest said:
What about using a hand throttle for when you don’t have enough feet for all three pedals?
Click to expand...
I've had one and used it quite regularly in the past. Certainly an option still.
 
85CUCVKRAWLER

85CUCVKRAWLER

Active Member
Location
Tooele
TJustin said:
Pardon my ignorance, but what options are we talking about more than just a different stall or valve body?
Click to expand...

As stated, TH350's are probably the most common trans found in any gear head community. You can change basically anything you want about them into any configuration. Further, if you need parts right then an there, youre gauranteed to find someone with a spare converter or pan in their trailer. You can even source a spare setup just by scouring FBMP.

32RH, not so much.
 
B

bobdog

4x4 Addict!
Location
Sandy
I don't know. A long time ago I read it's really not a strong enough way to engine brake. Only engaged in overdrive anyway unless you modify and won't hold up. Things may have changed and I never dove deep into the tech.
 
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