Chevy 4x4 4L60 (700R4) to NV4500 Swap

[Miller88]

Is the NV4500 super noisey? We had a NV3500 in a Wrangler that was super loud.

[aardvarcus]

My goal of hitting 20MPG will be mainly aero tricks, better tires, and maintenance. As much as I would like to do an engine swap or more drastic measures, I am planning on only keeping this truck about two more years and it has a recently rebuilt 350. In a few years I hope to do a complete truck mod and just get another one. I am looking at mainly good bang for the buck modifications in the meantime.

Aerodynamically, I can already tell the front de-cranking and air dam replacement have helped out, the next fill up will show exactly how much. Current upcoming aero plans are a tonneau cover and cab wing combo. I am trying to come up with the best/easiest/cheapest way to do it, while still maintaining relatively easy access to the bed. My current plan is to find a used tonneau, and then build a cab wing that sits on the bedsides. (I have looked at all the pickup diagrams on this site.) Also one of my bed sides has a huge dent in it, I need to pop that out to smooth the flow down the side. I would also like to build a lexan cover for the recessed bucket headlights, or alternatively swapping the whole grill to a model with composite headlights would do the same thing.

Tires, I am leaning towards Michelin LTX M/S2 in either P245/75R16 or LT235/85R16. I have been watching for a decent used set, but I may end up just buying new.

Maintenance wise I need to replace some EGR parts, door handles are all loose, interior needs some work, seat hurts my back, AC needs fixed, etcetera. While most of that doesn’t seem like ecomods, if I don’t fix those things I may end up driving my 2500HD that gets only about 13.5 MPG, so in a round about way they are ecomods.

As for noise, the NV4500 isn’t quiet, but I wouldn’t call it super loud. Granted the whole pickup is probably a little loud but the transmission noise isn’t any louder than anything else.

Speaking of the NV4500, I noticed mine gets a little warm from driving it home yesterday. I don’t think it is overheating, but it was definitely warm to the touch. I have ordered some PTO coolers for it, don’t need it overheating on me when it is even hotter outside. It might be the transfer case heating up the transmission, I need to check the fluid levels in both and make sure the transmission hasn’t dumped fluid into the transfer case and overfilled it. I may need to replace the input seal on the transfer case if that is occurring.

I am fully open for ideas and suggestions, that is why I am posting.

[Big Dave]

What you have done is a fairly common mod done by pickup guys – particularly when they don’t try to plow snow.

The NV4500 is not as rugged as the ZF6-650 but is much easier to find used. Your conversion sounds about like all the others I have heard of. The only quibble I had was I would have put fresh synchronizers in it when I had the NV4500 apart. Synchronizers are not that expensive and they are a wear item. But you can probably get away with what was in it.

I fully understand why you ditched the slushbox, over and above fuel economy. I had an 83 GMC with a 700R4 and destroyed five of them. Spectacularly. Parts and ATF scattered down the road. The 4L60E is nothing more than a tarted-up 700R4. You have freed yourself of much trouble.

Another thing. NV4500s have a reputation of unscrewing the nut holding the output shaft in place. I am told that reputable tranny shops have a sure-fire fix.

Your transmission probably is getting a bit hot. IIRC, the NV4500 does not have a cooler fitting. But you spend a lot of time in top gear which is a true overdrive. That gear mesh has some friction, so there is some heat build-up. My ZF6-650 has a cooler line. Stay with the Amsoil synthetic and watch the color. You should be OK but don’t expect the astronomical oil life a cooled transmission would get.

Looks like just the tranny swap gained you 3 MPG or so. That is exactly what I’ve heard from everybody who ever did such a swap . It is almost a +3 MPG no-brainer for a guy who has an unreliable 700R4.

I think 20 MPG is very doable. The stick opens new vistas of hypermiling. You will become a master of coasting. You can closely match engine RPM and road speed to keep the engine in a high load-low RPM regime which is where the best fuel economy is.

As for aero improvements, you’re in exactly the right place. There are plenty of pickup truck aero projects in here and you can find one that suits your needs. I found a flat tonneau got me a 1.5 MPG improvement over and open bed, but a sloped aerolid will give you about a three MPG improvement over an open bed. This site is chock-a-block with belly pans, grille blocks and air dams.

As for tires, tire manufacturers are pretty close with rolling resistance figures, but two things stand out. Quiet tires generally get better MPG. Also the OEMs have to submit tire rolling resistance to the EPA so the EPA can come up with a MPG estimate (such as it is). Since MPG is a selling point, the OEM has good reason to fit the lowest rolling resistance tires he can get. Also, if you are not gonna mess with gearing (an expensive proposition for a 4x4) stay with the OEM-sized rubber. The factory boys do have a clue about those.

[Sporty Modder]

Full tonneau is pretty usable, though I am going with a half on my Bee in the very near future. More aero benefit and can be as cheap as a sheet of 1/2" plywood and a couple of 2x's.
Good to hear some progress.
Is the Celica gone?

[aardvarcus]

Well, I did another fill up, same as before except with the 1” lowered front and the reinstalled factory air dam, and got 18.4, so that was good for around 1MPG +/- a reasonable deviation. Looks like about three fill ups and I will have broken even on the air dam.

Yeah, I wish I had the syncros replaced, but I didn’t want to invest too much into the tranny swap at the time and I didn’t have the tools to change them myself. I don’t yet have an RPM meter on the truck, I want to get one so that I can actually see where I am at.

I still own the Celica, but it is going to be sold very soon for personal reasons. I don’t want to sell it and understand selling it and driving the truck is a poor financial decision, but it is something that I have to do right now so I will just leave it at that.

Back to the truck I got a good side view picture of the truck, so I will put it up against the template to try to get an idea for how the cab wing and tonneau should integrate.

[cRiPpLe_rOoStEr]

As long as your custom-fabrication skills go, you're gonna get some hard work trying to improve the aerodynamics at the front clip too.

[aardvarcus]

Well, I did a huge major mod to the truck a week ago, and got about 10 more MPG than I had been getting. I did a complete engine swap, transmission swap, transfer case swap, suspension swap, frame swap, and body swap. Completed it all in one day. I swapped all these parts from a 2005 Toyota Tacoma Access Cab 4x4 2.7L Manual. If you didn't know better you might just think I bought another truck.

I will start a build thread on the "swapped" project once I get started on it.

[Miller88]

That's a lot of work for one day!

The Tacoma is a good little truck.

[cRiPpLe_rOoStEr]

With the "compact" trucks getting bigger at each new generation, I wouldn't doubt that Toyota engine could provide reasonable performance if somebody attempted to swap one into a C/K 1500...