Question for all you 1-Ton owners...

[5Tractorguy]

I'm looking to buy and other 1-ton this year and have some questions regarding transmissions. Currently have an '88 1-ton, 4WD, 5.7/TH400.

I don't do a lot of highway driving but on occasion I need to, whether it's an out of state trip picking up tractors or in state. To travel well at 65mph would be great. The TH400 in mine has never ran right, always slipped, so I never really knew what the average top speed for a 400 is. And I know a lot of this depends on diff gearing too.

-Those that own standard transmission trucks (low 1st 4-speeds), what is your top highway speed? What can you travel comfortably at?

-With a TH400/TH350 transmission highway speed?

Any input is appreciated! I know these are old trucks and aren't for speed, not looking to do 80+ here...

[Tiger Joe]

We have a 79 c30 dump. Was a 350 with the sm465 and it struggled to do 65-70.

Doesn’t help the truck has 4.10 gears.

Swapped in a big block and nv4500 And it’s night and day difference

[Woodyboat]

My '86 Big Dooley has the 454/TH400 combo with the Dana 70/4:11 gearset. It just sings along at 70mph all day long. Yes, I know that I'm twisting it a little high but I'm not sure exactly how high because I don't have a tach.

[sweetk30]

first off top gear in both the th400 and sm465 is 1:1 ratio . so give or take a few rpm for the auto convertor .

next as you said its the gears in the axle and dia of the tires .

an over drive trans swap such as a 4l80-e or nv4500 stick would be a huge help . if 4l80-e is done look at www.usshift.com for a super nice stand alone controller with TONS of features .

last play with this cool tool . http://www.grimmjeeper.com/gears.html

and if you don't have one now . . . . GET A TACH so you know what rpm you are spinning . NOT what you think your spinning . there is a big difference in them .

[MrBeast]

My old 85 CC Dually started with a TH400, it sucked, I canned it and went for an NV4500, with 31" tires and 4.10 gears, that truck would run 80 mph all day long without breaking a sweat, it would hit 100 if you weren't careful.

IMHO it is the only way to go, well that or a 4L80E

[mongocanfly]

heres the rpm calc I use....http://www.csgnetwork.com/multirpmcalc.html

when my 81 1T had the 350/sm465/4.10s in it, it was screaming at 70-75mph.....switched to lq9,6.0/nv4500/4.10s...like stated ...nite/day difference...and also like stated it will hit 100mph with no effort....I tow a 9500lb loaded trailer with mine and it doesn't break a sweat at 75mph loaded..

[v30crewcab]

my 88 tops out somewhere around 105-110, but I have a nv4500 and cummins!

[5Tractorguy]

Thank you for all the input!

So it looks like either stock manual or auto transmission will still have trouble reaching 65 comfortably, differential providing... Could get fancy and add a brownie or gear vendor though.

Main reason here is I need a truck that can get down the highway and I plan to buy these out of Missouri. Friend of my fathers has a friend out there who was going to round up a truck or two for us. We were going to road trip out and drive them back.

But seeing that highway speed might be an issue, maybe I'll have them transported back. Would be cool to take a road trip though.

Just some thoughts, but good possibility I'm going to open some cans of worms here...

How rugged are the NV4500's? I've heard they are prone to problems. Will they mate to the Chevy bell housing easily?

This TRANSMISSION has been for sale here for a while, an Eaton 5spd. If it has 5th as an OD, I wonder if it would mate to the Chevy bell housing? Did come from a C60.

Anyways, I don't want to complicate this too much. I need another daily driver more so than another on-going project truck. Got one of 'em already!

[57NAPCO]

I have a K30 454/400 and a 454/sm465, I prefer to keep the original setup and ad a gear vendors overdrive.

[sweetk30]

that c-60 eaton trans is NON-od . just has extra gear to split is all. and the input shaft is HUGE compared to a 1ton down .

nv4500 trans come in gm trucks stock . just 93-up .

strong trans just have few weak spots . once fixed there good units.

if looking for one keep a eye open for a W/T truck in the 88-98 body style with 4.3v6 engine . they did come with the nv4500 since its a work truck . my buddy got one cheep this way . inside was like new when we pulled the top to verify condition .

[57NAPCO]

Drive em back! speed should not be an issue on a long drive in a new truck. Take side roads and check out the scenery. I’ve driven across the country many times at 50 MPH

[csdineley]

Mine's not a 1 ton but a 3/4 ton with 350, sm465, and 31' tires. Originally my truck had 4.10 gears. 70 mph was about 3200 rpm's. I switched to 3.42 gears and now run 70 mph at 2500-2600 rpm's.

[MrBeast]

The 93-95 GM NV4500 has a different case than the 96-00, the 96-00 has an identical case to the Dodge NV4500, the dodge and late GM NV4500 is the one you want, although GM and Dodge run a different input shaft, and the dodge diesel and gas run a different one.

The problem with the NV4500 was with the 5th gear nut backing off, there are a variety of fixes for this such as the torque king shaft which I recommend if you are running more than 400 hp, otherwise stock is really fine.

[cal30_sniper]

My truck started life as a 454/TH400/3.73 gear with 31" tires. In that configuration, I never had trouble maintaining highway speeds up to 80mph (lots of trips on I-10 out in West Texas). I don't know if I would recommend 4:11s at that kind of speed, but it was never an issue for me with the 3.73s. 65-70mph was simply a non-issue, that's what these trucks were originally designed for. Nobody worried about running these things 70-80mph when they were new, I don't see any reason you should now either.

I eventually swapped my TH400 for an NV4500. The overdrive is nice, especially at 70+ mph, but not necessary. I tow in overdrive, but you have to watch the heat, as it ramps up quicker than in direct drive. I really wouldn't recommend towing anything heavy in overdrive with an auto, even a 4L80e. With either trans, if you're towing something heavy enough to require running in direct drive, you really shouldn't be pushing faster than 65mph or so anyways, so the gearing is a non-issue at that point.

Unloaded, with the NV4500, the truck will easily do 85-90mph cruising. However, neither the state troopers or the gas mileage are very friendly at those speeds. Not to mention, the windnoise gets pretty intense above 70. As an aside, I noticed no measurable change in gas mileage driving 65mph between the TH400 and the NV4500. The overdrive allows the engine to spin slower, but it has to work harder. Gas mileage comes out in a wash as a result. Above 65, aerodynamics play a bigger role, and your gas mileage is going to suffer regardless of drivetrain combination.

The NV4500 I got came out of a 98 GM truck. The GM transmissions didn't have the 5th gear problems that the Dodge transmissions do. A GM 4WD NV4500 has the round pattern transfer case that will bolt right up to your existing round pattern 205. That would make a sweet setup.

[MrBeast]

Originally Posted by cal30_sniper

My truck started life as a 454/TH400/3.73 gear with 31" tires. In that configuration, I never had trouble maintaining highway speeds up to 80mph (lots of trips on I-10 out in West Texas). I don't know if I would recommend 4:11s at that kind of speed, but it was never an issue for me with the 3.73s. 65-70mph was simply a non-issue, that's what these trucks were originally designed for. Nobody worried about running these things 70-80mph when they were new, I don't see any reason you should now either.

I eventually swapped my TH400 for an NV4500. The overdrive is nice, especially at 70+ mph, but not necessary. I tow in overdrive, but you have to watch the heat, as it ramps up quicker than in direct drive. I really wouldn't recommend towing anything heavy in overdrive with an auto, even a 4L80e. With either trans, if you're towing something heavy enough to require running in direct drive, you really shouldn't be pushing faster than 65mph or so anyways, so the gearing is a non-issue at that point.

Unloaded, with the NV4500, the truck will easily do 85-90mph cruising. However, neither the state troopers or the gas mileage are very friendly at those speeds. Not to mention, the windnoise gets pretty intense above 70. As an aside, I noticed no measurable change in gas mileage driving 65mph between the TH400 and the NV4500. The overdrive allows the engine to spin slower, but it has to work harder. Gas mileage comes out in a wash as a result. Above 65, aerodynamics play a bigger role, and your gas mileage is going to suffer regardless of drivetrain combination.

The NV4500 I got came out of a 98 GM truck. The GM transmissions didn't have the 5th gear problems that the Dodge transmissions do. A GM 4WD NV4500 has the round pattern transfer case that will bolt right up to your existing round pattern 205. That would make a sweet setup.

That is interesting because with the NV4500 swap I saw my mileage at 70 mph go from 8mpg to 12, with a carbed motor!

[Tiger Joe]

Originally Posted by cal30_sniper

My truck started life as a 454/TH400/3.73 gear with 31" tires. In that configuration, I never had trouble maintaining highway speeds up to 80mph (lots of trips on I-10 out in West Texas). I don't know if I would recommend 4:11s at that kind of speed, but it was never an issue for me with the 3.73s. 65-70mph was simply a non-issue, that's what these trucks were originally designed for. Nobody worried about running these things 70-80mph when they were new, I don't see any reason you should now either.

I eventually swapped my TH400 for an NV4500. The overdrive is nice, especially at 70+ mph, but not necessary. I tow in overdrive, but you have to watch the heat, as it ramps up quicker than in direct drive. I really wouldn't recommend towing anything heavy in overdrive with an auto, even a 4L80e. With either trans, if you're towing something heavy enough to require running in direct drive, you really shouldn't be pushing faster than 65mph or so anyways, so the gearing is a non-issue at that point.

Unloaded, with the NV4500, the truck will easily do 85-90mph cruising. However, neither the state troopers or the gas mileage are very friendly at those speeds. Not to mention, the windnoise gets pretty intense above 70. As an aside, I noticed no measurable change in gas mileage driving 65mph between the TH400 and the NV4500. The overdrive allows the engine to spin slower, but it has to work harder. Gas mileage comes out in a wash as a result. Above 65, aerodynamics play a bigger role, and your gas mileage is going to suffer regardless of drivetrain combination.

The NV4500 I got came out of a 98 GM truck. The GM transmissions didn't have the 5th gear problems that the Dodge transmissions do. A GM 4WD NV4500 has the round pattern transfer case that will bolt right up to your existing round pattern 205. That would make a sweet setup.

Gotta disagree with a couple things here

1- these trucks in stock form were designed to run 55. That was the national speed limit until 87. Not saying you can’t, but running 80 at 3000+ rpms isn’t my ideal cruising situation.
2- if you don’t see a change in mpg something is wrong. If you’re cruising at 65 with the nv4500 that motor is turning 25% slower than the th400.

[Woodyboat]

Originally Posted by Tiger Joe

...these trucks in stock form were designed to run 55. That was the national speed limit until 87.

Well... that's what they TOLD us at the time. LOL

But in reality, NOBODY actually drove 55. That was just considered disgraceful to go that slow.

[cal30_sniper]

Originally Posted by Tiger Joe

Gotta disagree with a couple things here

1- these trucks in stock form were designed to run 55. That was the national speed limit until 87. Not saying you can’t, but running 80 at 3000+ rpms isn’t my ideal cruising situation.
2- if you don’t see a change in mpg something is wrong. If you’re cruising at 65 with the nv4500 that motor is turning 25% slower than the th400.

The 55mph limit didn't get signed into law until January 1974, long after any squarebody truck and powertrain combo had left the design and development phase and hit the streets. The trucks were designed to run 60-70mph, and they do just fine at that.

There's nothing magical that happens in your engine at 3000rpm. Whether you drive 1000miles at 55mph, or 1000miles at 80 mph, the engine sees the same number of revolutions regardless. At 3000rpm, you are still far from the upper envelope the engine was designed to operate reliably at.

I didn't see any notable mileage increase, but I was already in a good state of tune getting good MPGs. I went from about 13mpg before the NV4500 to about 13mpg afterwards. I've gotten up to 14.5 on the highway, but I got that a couple of times with the TH400 also. Around town is still 8-10mpg, just like it was before.

[HunterRotten]

My 2011 subaru does 3k rpm at 70 mph, nothing to worry about..

[cal30_sniper]

Originally Posted by HunterRotten

My 2011 subaru does 3k rpm at 70 mph, nothing to worry about..

Shoot, if we're talking newer stuff, I did a Florida to California and back to Florida trip in my '91 BMW a few years back. I-10/I-8 the whole way at 80-90mph. Small diameter tires, 3.73s, and the short 5-speed overdrive had that straight six turning 3500rpm most of the way. That motor had 260k miles on it at the time.

We did a Texas to Maryland trip in my brother's 71 Charger a few years ago as well. Bone stock original 383 with a 727 and 3.20 something rear gears. No A/C trip through the south in the summertime, but that engine hummed like a top the whole way. Seriously though, how many decades did Americans drive cars without OD before turning highway RPMs became this mega concern?

[DieselSJ]

454/TH400/4.56 with 235/85/16 tires and I'm spinning 3100 or so at 65. If I drove more highway, an overdrive would be at the top of my list. It is near the top anyway and I only drive it 6k-7k miles per year. Still deciding between 4L80E and a TKO.

[5Tractorguy]

Some good info here.

Well I suppose they are what they're going to be. I'm still going to round 1 or 2 up out there, preferably standards. I've just about had my fill of automatics for the time being. And drive them back if all goes according to plan. I really want to do it for the experience. It would be fun to take a week or two and go since the farthest I've ventured out of NE is Pennsylvania.

55-60mph is good enough for me, I'll just be "that guy" on the highway! Beats not being able to get over 45 now due to a slipping trans. And at least I know there are upgrades I can do if I want.

Once again, thanks for the info!

Alright folks, lets not derail this into a I know more than you contest.

[tucsonjwt]

I have a C20, not C30, SRW, 454, SM465, 4:10. Up around 70 mph on the highway the old Bb is screaming (not to mention wind noise), so I don't go there very often. I do have a Gear Vendor unit in it but that does not seem to help much. I think the 4:10 is the culprit but I might just have a lemon truck.

[cal30_sniper]

Originally Posted by 5Tractorguy

Some good info here.

Well I suppose they are what they're going to be. I'm still going to round 1 or 2 up out there, preferably standards. I've just about had my fill of automatics for the time being. And drive them back if all goes according to plan. I really want to do it for the experience. It would be fun to take a week or two and go since the farthest I've ventured out of NE is Pennsylvania.

55-60mph is good enough for me, I'll just be "that guy" on the highway! Beats not being able to get over 45 now due to a slipping trans. And at least I know there are upgrades I can do if I want.

Once again, thanks for the info!

Alright folks, lets not derail this into a I know more than you contest.

I'd go with the stick trucks every time if I had the choice. Never have I had a stick that I wished was an auto. Can't say that about most of the autos I've owned. Personal preference, but the manual trans trucks certainly seem to be more sought after.

Sounds like you've got a good road trip ahead. You probably already know this, but pack a spare go-bag with extra fluids of all types, a basic tool kit, and a portable air pump if you've got one. Make sure at least one of the trucks has a good spare and working jack with the right size lug wrench. If you pack a spare distributor (for the coil, cap, rotor, and ignition module), and a spare fuel pump, there's not much really else that can go wrong with one of these old trucks. If you stick to the 2-lanes and backroads, you shouldn't feel like you aren't able to keep up with traffic while running 55-60. Once you get out of New England, you can actually make pretty decent time running secondary roads instead of the interstates and main highways. Perfect time of year to start looking into hitting the road too. This way you won't mind the A/C being discharged on whatever truck you buy, haha.

[Alex V.]

My truck is an '85 C3500 with a bone stock 454, tired TH400, and 4.10 gears with the correct 235/85/16 tires. When pulling a decent load (i.e. car on a trailer) hitting a hill at less than 50 MPH takes a lot more pedal to keep speed over the hill than if I'm going at least 55 when I start up the grade. The transmission has a strange drag/mild vibration that it hasn't always had, but that being the case it feels best at about 60 but doesn't mind upwards of 65. It'll do 75+ if asked, but sustaining over about 65 puts a dent in gas mileage and I just don't care to push the truck that hard for long distances.