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OD trans behind gen III motor, nv3500 vs nv4500

Mark1968

Mark1968

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I am fairly certain that I am going to swap out my 465 for an overdrive manual when I get around to installing my 6.0 next year.

I've done some reading and some say that the nv3500 is only rated for 300ft lbs and I think that the 6.0 makes a touch over that. I would almost prefer the 3500 due to the better gear spacing/ratios as this will be a driver when finished. Also I'm seeing nv4500's in the $500-1300 range and an nv3500 can be had for much less. I found a '98 or 99 3500 today on CL and as I understand it those years are more reliable but at the same time I don't want to buy something I'll break.

What do you guys think?
 
Well, what 6 speed would you recommend for the guy? Assuming 4WD, all I know that'll work might be the ZF 650. Not cheap, not sure what'd be needed to swap though. NV5600 is just a fricken monster, more swap issues too. Again, not cheap.

Could go T56 and divorced T-case, also not cheap.

6 speed allison would be slick, again I'm going out on a limb and guessing not cheap...and also not manual. :doah:

To the OP, I'd consider trying the NV3500 for a few reasons. First, it is cheap...so if you kill it you haven't lost much. I think it'll live though, as long as you don't take it to the drags, or powershift the hell out of it. You'll gain much smoother shifting and better gear spacing. The NV4500 is nice, but the only gain you'll have is crisper shifting, and an overdrive. The horrible gear spacing is still the same as the SM 465.

Last might be the SM 465 and maybe a Gear vendors, or ranger under/over drive box. :dunno:
 
I thought 6.0 trucks came from the factory with the zf650. Yes, this is more expensive, but I thought it was a feasible swap?

If I was putting a 6.0 in, that is the trans I would want.

Are you worried about the t-case front output ending up on the wrong side? I don't know about the t-case options.
 
The nv3500 is a nice shifting trans. Yes torque is rated at 300ftlbs pretty sure thats input. Its all about how you drive it really.

If you're not locked in.on a 6.0 you could consider a 5.3 or even 4.8 to match the swap better. I've got one behind a 400hp 355 and a bang 1st to 2nd to 3rd pretty hard.
 
Yea I am set on the 6.0 since I already have it. Current setup is 350/465/208. 3:73's and a 33" tire.
 
I have a friend who abuses his 350HO with a 3500 on 37s pretty hard and he has never had a problem. But, if you really flog on that 6.0 that 3500 will not survive long. But, like was said before, its all in how you drive it.

I would go 4500 just for the peace of mind it brings, yes the gear spacing blows, but its a good reliable trans, and down the road you can always swap a 6 speed in and sell the 4500 for good cash. If you ever decide the swap is worth the trouble.
 
Richcz28 said:
I tried to do a little more research before I give poor advice. I found these two points of interest.

http://coloradok5.com/forums/showpost.php?p=2501352&postcount=13

http://www.performancetrucks.net/fo...2/6-speed-zf-s6-650-transmission-swap-404105/

If you do decide to go with an nv4500, chevy305 put an awesome shifter on his.

http://coloradok5.com/forums/showthread.php?t=181502&page=96
Click to expand...


That 6 speed swap is sweet, but I just replaced my floors and installed new poly body mounts. So cutting my floor and a 3" bl are out.
 
Mark1968 said:
That 6 speed swap is sweet, but I just replaced my floors and installed new poly body mounts. So cutting my floor and a 3" bl are out.
Click to expand...


I don't know that you would need to do any of those things to make that swap work.

I believe you will have to modify the trans tunnel even if you go a nv4500.

I replaced my floor in the spring, but eventually you get over cutting holes and patching holes and cutting more holes I have cut many new holes since then. It just becomes part of it.
 
You'll be doing the same floor pan mods regardless of which transmission you put in. All three have the shift tower in the same place. No body lift will be required with the ZF6. It is a massive transmission but is not any taller than the SM465.

The ZF6 has a 29 spline output shaft. That means you are going to be finding an np261 input shaft to install into a pass side drop np241 to swap it in.

The ZF6 has very good gear ratio splits just like the NV3500 but it is mega beefy in comparison. The NV4500 is just an SM465 with an overdrive tossed into the mix.

I've abused NV3500s behind diesel engines offroad and never hurt it. The 99+ NV3500s are a much better transmission than the earlier variants. They used them behind 4.8l engines until 07
 
Russell said:
You'll be doing the same floor pan mods regardless of which transmission you put in. All three have the shift tower in the same place. No body lift will be required with the ZF6. It is a massive transmission but is not any taller than the SM465.

The ZF6 has a 29 spline output shaft. That means you are going to be finding an np261 input shaft to install into a pass side drop np241 to swap it in.

The ZF6 has very good gear ratio splits just like the NV3500 but it is mega beefy in comparison. The NV4500 is just an SM465 with an overdrive tossed into the mix.

I've abused NV3500s behind diesel engines offroad and never hurt it. The 99+ NV3500s are a much better transmission than the earlier variants. They used them behind 4.8l engines until 07
Click to expand...


**** Joe Gibbs used them behind 400hp super charged 4.8s that I believe he built in heavier versions like crew cabs, not just standard cab shortbeds, and I havent seen any complaints from the 99+ guys in regards. I have this sentiment about the nv3500 it goes like this.

When the actual nv3500 came out it was rated 300ftlbs input torque, mind you there were predecessors to it that externally looked just the same but had different internals and were weaker. Than as years went buy it seemed they wanted to prolong the use of the trans design behind more modern motors with more power. They made things from better materials, reworked the bell for a hydraulic throwout, and put the trans behind stronger and stronger motors but never changed the power rating...

You have to figure to give something a 300ftlb rating there has to be a margin of error. Just like a rating on anything its normally 20-30% before its actual breaking yield. So considering that you could look at that number more like 360-390ftlbs of torque before your actually doing damage to the trans or on the brink of it with average abnormal driving.

Then theres weight. Although probably not an example in your case having the same torque rating for something that weights 6000-7000lbs and something that weight 3000-4000lbs makes no sense. Lighter load the actual breaking point should go up.

Just saying I think theyre under rated. Are they the greatest trans in history no. But are they a good cheap easy option? Yes. Especially if you can live with the sentiment of keep a spare around just in case and swapping it out doesnt scare you.
 
Now that I am on a computer and not on my phone I will type a bit of a better reply...

IMO, rock the NV3500! Like Vinnie said, the newest transmissions are miles ahead of the older versions. They don't fall out of gear, have much better designed internals and are considerably stronger.

I had a 96 pickup with an NV3500 in it that I did have suffer a failure. It started grinding really badly in 2nd gear and made an awful whining noise. When I pulled it out and took it in as a core for a new transmission the shop told me that the reason why it failed is that it had been filled up with 80w90 gear oil instead of the 5w30 syncromesh fluid it is supposed to run. Sure, it was behind a 4.3L V6 but I beat the crap out of that transmission and never hurt it.

My next experience was putting one into an old K10 I had on 35" boggers with 2.73 gears and a naturally aspirated 6.2L diesel. That truck couldn't maintain speed in 5th gear even at it's top speed of 58mph. The engine just didn't have the power to overcome the crappy gearing. I beat the ever living crap out of that truck offroad and never hurt the transmission at all. I later swapped the NV4500 I had in my old K25 with the same 35" boggers, 4.56 gears and a turbocharged, souped up 6.2L diesel with the NV3500 from my K10 because I hated the gear spacing in the 4500. Again, I flogged that truck which had much more input torque than the transmission is rated for and never hurt it.

Then I swapped that entire drivetrain over into a K5 with 37" boggers and again flogged it without ever hurting it.

I sold the K5 with that drivetrain in it and he drove it on the highway something stupid like 10hrs home and it was the rear driveshaft that failed. Not the transmission.

I have a good understanding that the earliest Getrag HM290s and the earliest NV3500s did have issues that gave them a bad name, but the 96-98 and especially the 99-07 NV3500s are a totally different animal. They'll hold up to some abuse before they fail. Yes, you can definitely break one if you try but if you have any sense in how you drive it then it'll last.

The ZF6 is definitely a decent option if you are considering a high power engine or plan on shock loading the drivetrain regularly. Even they suffer from a weak input shaft and occasionally their housings will explode under shock loading. They have a great gear spacing like the NV3500 and shift very nicely. They have a granny low like the NV4500s in the 5. something range and a decent OD gear of .73ish. They will swap into place of an NV4500 being the same overall length from bellhousing to tailshaft. They use the same clutch and input shaft as the NV4500. The top side of the transmission is roughly the same height as the older transmissions but it is quite a bit deeper. The NV4500 has the tail shaft adapter on it with the 5th gear inside which is where the ZF6 fits the 6th gear hense the same overall lengths.

The biggest issue with the 29 spline output shaft. You need to swap the input shaft on an NP241 from a NP261 to make it fit. The part that makes that tough is that somewhere in there the planetary gears were changed and I am not 100% sure that the newer input shaft will fit into the old pass side drop 241 cases.

All in all, I'd go NV3500 first. If you break it, then you already have everything in place to simply swap the ZF6 in and convert a transfer case (or install an aftermarket piece)
 
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