Manual to auto swap.

[hunters628]

Got a couple questions. I’m wanting to change over my k10 from a sm465 to an auto of some sort. I’m just about to drop a 5.3 in the truck. Truck will be my daily and 80% freeway use. I have a slide in camper that I will also have in the truck sometimes. I’m not big into wheeling but do hunt and will drive through the woods and beat up roads to camp and stuff. I have 3.08 front and rear with 31” tires. I would like to stick with a th350, th400, or 700r4. Looking for recommendations on this. I’ve already had the tranny controls deleted from my ecm so I don’t want to run a 4l60e. If anyone has something they’re willing to trade for my low mileage 465/208 or make a deal on let me know. All input is welcome! Thanks

 

[nvrenuf]

With your use I’d go for an overdrive. A well built 700 should do fine for you.

 

[SquareRoot]

Why would you want an overdrive with 3:08 gears?

 

[Frankenchevy]

Pros and cons to all of them. Regear axles to utilize an OD auto. 400 is strong but more hp losses. 350 is a decent tranny if you don’t want to regear with less hp lost, but not as stout as a 400...

 

[hunters628]

700r4 would have me at approx 1800 rpm with 3.08s and 31s doing 75mph. Th400/th350 would be 2500 with the same setup at 75. Not sure which would be better. Unloaded I would probably be in OD a bit. But with the camper I would be 3rd, which is the same as the th trannys. I’ve been wanting to get a 6 lug 14bsf with 3.73s and regear the front to match. 3.73s with a 700 would be 2100 in od at 75mph. That sounds like the sweet spot to me. What year range 700 is desirable. Was it offered with a np205 or will it be easier/cheaper to get a 208 setup. The non electronic 4l60 any better than a 700 or is it the same thing. Any easier to get? Sorry for so many questions. Thanks

 

[Matt69olds]

What engine controller do you plan to use with the 5.3? Is it capable of controlling a 4L60E? If so, that would be the way to go.

 

[mcarlo86]

700r4 would have me at approx 1800 rpm with 3.08s and 31s doing 75mph. Th400/th350 would be 2500 with the same setup at 75. Not sure which would be better. Unloaded I would probably be in OD a bit. But with the camper I would be 3rd, which is the same as the th trannys. I’ve been wanting to get a 6 lug 14bsf with 3.73s and regear the front to match. 3.73s with a 700 would be 2100 in od at 75mph. That sounds like the sweet spot to me. What year range 700 is desirable. Was it offered with a np205 or will it be easier/cheaper to get a 208 setup. The non electronic 4l60 any better than a 700 or is it the same thing. Any easier to get? Sorry for so many questions. Thanks

Definitely should re-gear it, especially if you are doing any towing. I don't think the np205 was ever offered with a 700R4. Ideally, looking for a 4L80E would be the best towing friendly OD transmission.

 

[hunters628]

What engine controller do you plan to use with the 5.3? Is it capable of controlling a 4L60E? If so, that would be the way to go.

I’m using the stock ecu. I already had the vats and trans control deleted. I got a 4l60e with the motor but is was trashed apparently so I prematurely took it to the junkyard since I don’t have much room to keep it. My garage is barely big enough for my truck.

 

[hunters628]

Definitely should re-gear it, especially if you are doing any towing. I don't think the np205 was ever offered with a 700R4. Ideally, looking for a 4L80E would be the best towing friendly OD transmission.

I just worked out a trade for a th400/208 combo along with a tilt auto column pedal set and some other body parts I needed so I will be using that trans now. Maybe in the future I’ll get an 80e. But for now this will do for my purposes!