Ok, So I want to put the 3/4 ton axles in the CUCV. They are geared with 4.10s. Right now I have a TH400 with 10 bolts and 3.08's. My only sense of urgency is that the rear axle sounds like its about to blow up. Kinda the same sound you get as you start to turn some metal on a lathe... So lets take a poll. I want to stick with an auto trans. So here are my options as I see it. Swap in a 700R4, 4l80E (will likely have to be one that I will need to purchase a controller for). Or leave the TH400 and get a gear vendors o/d unit. I want to go the most cost effective route. I am going to be running 4.10's and 35's. Daily driver with some moderate off roading.
CK5
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Transmission OPINIONS What to swap in.
- Thread starter us74k5
- Start date
i would run the 35 on the 4.10 first and see if you like it. never know.
other wise get a 4l80 from a factory diesel truck/van. thay have there own factory stand alone computer. it will be around 2.5" longer than th400 and shifter linkage will be diffrent.
other wise get a 4l80 from a factory diesel truck/van. thay have there own factory stand alone computer. it will be around 2.5" longer than th400 and shifter linkage will be diffrent.
4.10's with 35's on the highway is not enough. You'll be wishing you had another gear. I'm in the middle of changing mine too.
With 35'' tires and 4.56gears behind a 4l60 at 75MPH it be at 2298 RPM.
In your case, I'd lean towards the 4l80.
With 35'' tires and 4.56gears behind a 4l60 at 75MPH it be at 2298 RPM.
In your case, I'd lean towards the 4l80.
Desert Rat
Fetch the comfy chair
I'd avoid the Gear Vendors unit. When I bought my 76, it had one in it. I had a TH350 w/ the GV and an NP205. The length of it really caused problems once I wanted to lift the truck. You are adding about another 2 feet of length and reducing the length of your driveshaft. I sold my GV and never looked back. If you are staying stock height, not as much of a problem but any lift at all is going to cause angle issues. I wanted an OD as well. I drive long distances sometimes to wheel and I wanted the OD for the highway. I looked at Bowtie Overdrives (http://www.bowtieoverdrives.com) and decided to have a very reputable local transmission shop copy one of their 700R4 units. They beefed the 700R4 up and I couldn't be happier. I now have my OD and confidence that the unit is built strong. I also didn't want to have any electronics to worry about.
As of yet the only thing I found somewhat close to here (Idaho) is a 2wd 4l80e from a 91 box van with a 6.2. I have no idea what it would take to go from 2wd to 4wd. And after shipping I am guessing it would be almost easier to just get a gas one and buy a controller.
Ned Kelly
1/2 ton status
Also, do a calculation of your break even point of converting to OD and how many miles you'll have to drive to make it worthwhile. There is a calculation but I don't have it handy.
Oh as far as making it worth while, having O/D and the lower first gear will make it worth while. I don't care about making the money back in fuel. Also I don't mind too terribly much about dropping 2k on it, as long as its the best option and I don't find myself wishing i had done something else a few months down the road. Like I seem to have done so many friggin times.
I hear you can build a 700R4 pretty stout... but I have yet to see one survive any kind of abuse (i've burnt through three before I switched to a standard). I'd run the 4L80E b/c by the time you buy a quality overdrive unit for the Turbo 400 you could have picked up the 4L80E with the control cheaper... or convert the whole system over to a NV4500 (or SM465 if you aren't going to be on the highway much) and never worry about it (I'm a standard guy though).
From what my tranny guy has told me on going through my 700R4 is that their is some updated part to put in it sence we build it last time, that should make it plenty strong for my needs. Then I will not have to worry about electronics.
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I don't want a manual. I love them, but not for a daily driver. Right now I think im just going to wait around a bit, looks like my axles wont be ready to swap in till February anyways. So I will just keep looking around and see what I can find.
79rustyk10
3/4 ton status
Id lean to the 4l80E if the cash for it isnt a problem
Ned Kelly
1/2 ton status
Well for a full size rig I think 4l80e is the best way to go. Like ManChild said, better to spend more now, than beef up a 700r4 that could fail later. I think the higher initial cost of a 4l80e and stand alone computer control will be less than two built 700r4's. I've seen a few built 700r4's fail, and it seems a 50/50 chance on it's longevity depending on use. Some have succes with the 700r4, some don't. Maybe get an Atlas or Klune instead and retain your TH400 due to simplicity and robustness. I know it's a hard decision what to do.
2 things. search 4l80-e or 4l80 here and read up on tail shaft swap or adaptor needs. lots of pics in the big tread.
then dont forget th400 and 4l80-e same 1st/2nd/3rd/reverse but od in the 4l80-e.
700r4 has the deeper ratios on gears.
then dont forget th400 and 4l80-e same 1st/2nd/3rd/reverse but od in the 4l80-e.
700r4 has the deeper ratios on gears.
Desert Rat
Fetch the comfy chair
The 700r4 gets an undeserved bad rap for not being strong but that isn't true. The early 700r4's were very poor but they corrected much of the problems in later models. Do a search on them and you will see what years to avoid. And, once you have yours built up by a reputable shop, they are easily as strong as any other transmission minus the controller box. Go to the Bowtie Overdrive site and read up on them. I actually called BO and spoke at length to one of the guys and learned a lot about them.
Ten_Bucks
1/2 ton status
TransGo makes a kit to convert a 4L80E to run a vacuum modulator like a TH400 does so it eliminates the need for a stand alone TCM. They're less than 150 bucks if you know where to look. But if you still don't want to go that route, then go with the 700R4.
Scott
Scott
Hells nah. With the 3.08 and 33's I find myself wishing I had an overdrive on the highway. My goal RPM at 65mph is 1800 rpm. An overdrive on a 700r4 would put me right there. The 4l80E gets me pretty close too. Remember its a diesel!
COCHEV
1/2 ton status
i have th400s in both my rigs and despirately want overdrive as well. (4.10s and 35s also) and even more than the milage help i think its just less wear and tear on the motor.
I don't like that there are so few options. the 700r4 being the cheapest- sorta cause you'll most likely have to have it rebuilt. the nv4500 and 4l80 bring a higher initial purchase and seem to add up to a heafty price tag plus are hard to even locate...
I think i'm now leaning towards a 700r4 in my work truck and the burb might just get the sm465 and limited highway use.
I don't like that there are so few options. the 700r4 being the cheapest- sorta cause you'll most likely have to have it rebuilt. the nv4500 and 4l80 bring a higher initial purchase and seem to add up to a heafty price tag plus are hard to even locate...
I think i'm now leaning towards a 700r4 in my work truck and the burb might just get the sm465 and limited highway use.
kauzenkaos
1/2 ton status
id go 4l80 i picked one out of my core pile i figure im in it about 1500 with a complete ohaul torque converter transgo shift kit and a becontrols trans controller and harness. with 4.56s and 35s it turns about 2200 rpm at 65. not as low of a 1st as my 700r4 but a definite million times stronger. 4l60s 700r4s are pos's unless you enjoy broken reaction hubs and failed pumps. had a customer break a reinforced reaction drum called the beast the other day in a stock trailblazer. real great design who wants 3rd or reverse?
ps 700 for sale. upgraded 13 vane pump and a beast reaction drum. surprise surprise just overhauled lol
ps 700 for sale. upgraded 13 vane pump and a beast reaction drum. surprise surprise just overhauled lol
