Need help picking a transmission (1 Viewer)

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badsamaritan

badsamaritan

Joined
Feb 16, 2011
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I recently bought back a rig I had sold some 10 years ago and would like to start with changing out the trans. Here's my current setup:

1969 FJ40
5.3L Vortec (LM7)
SM420
3spd transfer case
2" body lift, SM420 didn't require any floor mods
stock axles

Primarily looking to get Overdrive or at least 4 useable gears, the compound 1st doesn't do me any good as I drive mostly in the city. Doing some research here I had a few questions:

1. Does going to NV4500 require floor mods and removeal of the frame crossmember? Can I still use my 3spd case?
2. Any pros to going with the H55F? Saw a few comments that the power of the LM7 might be a issue or the OD isn't low enough.
3. Do any of the 4L60/65/70 trans's fit? Seemed the overal length could leave you with some weird driveshaft angles.
4. Any support for the newer Tr-4050? - (Just saw AA has an adapter to my 3spd t-case)
5. Anything I'm not thinking off AX-15, NV3550? etc.?

Thanks in advance
 
Last edited:
Are you wheeling it? Ax-15 would probably be a easier drive than the nv4500 based on my research. Its not near as strong.
 
I’ve got the h55/split case combo. Handles 5.3 power just fine, there’s lots of folks running them. I have 4.11 gears, 33” tires, and in 5th gear I’m at 85mph at 3200rpm. It’s also a short driveline combo with only one adapter to the engine. The bulk and ratios of the NV4500 are also nice if you are ok with how truck transmissions shift. 4l60/65 will fit and angles will work out fine depending on how much lift you have but you will have a short rear shaft. I believe the TR4050 is quite similar to the NV4500, just has a slightly higher first gear ratio and is half an inch longer. It is also smoother, lighter, and quieter during operation. Not too sure on mods associated with installation on it, do some digging on here. Axis industries offers an adapter to the LC split case.
 
SipLife said:
I’ve got the h55/split case combo. Handles 5.3 power just fine, there’s lots of folks running them. I have 4.11 gears, 33” tires, and in 5th gear I’m at 85mph at 3200rpm. It’s also a short driveline combo with only one adapter to the engine. The bulk and ratios of the NV4500 are also nice if you are ok with how truck transmissions shift. 4l60/65 will fit and angles will work out fine depending on how much lift you have but you will have a short rear shaft. I believe the TR4050 is quite similar to the NV4500, just has a slightly higher first gear ratio and is half an inch longer. It is also smoother, lighter, and quieter during operation. Not too sure on mods associated with installation on it, do some digging on here. Axis industries offers an adapter to the LC split case.
Click to expand...

Thanks for the info! Are you running the Marks off-road adapter? AA is listing it for 2600 which seemed crazy for a single adapter
 
badsamaritan said:
Thanks for the info! Are you running the Marks off-road adapter? AA is listing it for 2600 which seemed crazy for a single adapter
Click to expand...
I went AA but you can also go marks, doesn’t matter. Where are you getting $2600 from? You need part numbers 712500T and 712532. That comes out to around $1200 plus shipping.
 
badsamaritan said:
Thanks for the info! Are you running the Marks off-road adapter? AA is listing it for 2600 which seemed crazy for a single adapter
Click to expand...
No reason to run Mark's adapter... you'll also need an AA flywheel... call advance adapter. They're very helpful and will tell you what you need


www.advanceadapters.com

NEW VENTURE 4500/CHEVY BHSG

Chevy V8 & V6 engine to the 1993-95 GM NV4500 5 speed, adapter bellhousing kit.
www.advanceadapters.com www.advanceadapters.com
www.advanceadapters.com

GEN-3 VORTEC MANUAL TRANS KIT LUK CLUTCH

Flywheel and Clutch kit for LS-Series / Gen 3 engines
www.advanceadapters.com www.advanceadapters.com
 
ok I am pretty sold on H55F after talking here and to a few friends. I guess my last question is are any tunnel or frame crossmember mods needed? I think there is a 2" body lift on the rig. That amount of body lift seems to clear the SM420, tcase and the twinstick conversion. I thought I had seen something about cutting and turning the frame crossmember but wasn't sure if that was for newer FJ40's
 
I got a cover from a FJ60 transmission hump that I am having grafted on the 78 transmission hump cover. That will put the holes over the shifters.

Manafree has an FJ60 crossmember that can be cut to fit the frame and weld up and will bolt up to the isolator that bolts to the H55F. If you can use a 2F bell housing it will support the transmission and transfer case like it did with a 4 speed.
 
I forgot the application was for a 5.3 and everything needs to move forward.
 
I see you like the h55 option, which is nice. The NV4500 can be installed with the shifters in factory positions with a modified t-case shift lever. No mods to the torque tube. With the rear axle in the stock position the D/S will be 2 to 3 inches shorter. I moved my axle back 3 inches for a stock driveshaft length. You won't need to change the flywheel/clutch for the NV. Different spud shafts for 3sp, 4sp, split case options but all available.
 
badsamaritan said:
ok I am pretty sold on H55F after talking here and to a few friends. I guess my last question is are any tunnel or frame crossmember mods needed? I think there is a 2" body lift on the rig. That amount of body lift seems to clear the SM420, tcase and the twinstick conversion. I thought I had seen something about cutting and turning the frame crossmember but wasn't sure if that was for newer FJ40's
Click to expand...
The NV is stronger and has a deeper overdrive. The H55 overdrive is modest, about 16~17% because the 6 cylinder wouldn't push the 27% in the NV.
With the 5.3 you have plenty of power to use the NV's 5th gear. With the 2F i had in front of an H55, 5th was a strain on modest highway climbs. I had one in my 87 BJ70
non turbo, and 5th was useless except on flat ground
 
My street 40 runs a sbc, 1st gen gm nv4500. I installed 3.70 thirds to make it more mpg friendly with 33" tires. According to an rpm calculator it runs around 2000 rpm at 60, and 5th has plenty pull. The po did the driveline swap. It was done prior to 96, so the adapter is really long and the crossmember was removed. I think later versions are about 4+" shorter. The shifter pretty much hits the stk hole. The transfer shifter was altered/bent and the hole was opened up slightly.
20220424_171219.jpg
 
I got around to driving a friends FJ40 with a TBI 350 and a NV4500 and I really like how it shifted and handled overall. So I think I am sold there....does anyone have a recommendation on a vendor for that trans?
 
I think it's a great choice. All the vendors I found were around $2600 if you didn't have a core. And they were getting scarce, but it was in the middle of c-c-covid when I was looking. I got sort of lucky after weeks of CL and Marketplace searches and found a early, broken GM for $325. 12 hrs of driving later, I got it home. $500 in parts to rebuild/replace broken parts. Rebuild process found on the internet.

I've forgotten the details since I did it (I was an expert a year ago) but, with some shaft swaps, a gas Dodge version will work also.

Some info:

NV4500 Transmission Info, Conversions, Reviews

NV4500 Transmission Info, Conversions Reviews
www.offroaders.com www.offroaders.com


The Novak Guide to the NV4500 Transmission

The Novak Guide to the NV4500 Transmission
www.novak-adapt.com www.novak-adapt.com

NV4500 new parts.jpg
 
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