Changing gear ratios: opinions/suggestions wanted!!

[CountKrunk]

What manual trans would you suggest? I want to accomplish the same thing. Ive had my eyes on the 4L80E but a 5 or 6 manual would be great as well.

 

[77Dmax]

Nv4500

 

[Grit dog]

The OD ratios in the newer 6, 8 and 10 speeds are not much higher than what was offered in the 80s.

I'm not here to argue but turning 3k at 70 is far from useless and is acceptable.

You’re correct on top gear OD ratios, and useless was a strong word. I’ll revise to undesirable, to me, and apparently the entire automotive industry and general public buying every kind of light duty vehicle…
Or we’d still have 1:1 transmissions in front of steep gears.

One BIG difference that the 6+ speed transmissions provide even though final trans OD ratios are similar to early OD transmissions is the ability to have super deep 1st/2nd gear and very manageable gear splits through the entire range, allowing for higher final drive ratios that effectively create even higher OD ratios without sacrificing pulling power out of the hole and the full range of speed from 1 mph to terminal velocity.
Not here to argue either but again, if 1960s and 70s automotive technology was better or desired, we’d still be using it.
And anyone who says they’d rather be screaming at 3-4k rpm’s all day long across the flyover states vs 2k or less is kidding themselves, living in the past for posterities sake or just instigating a typical antagonistic Facebook type discussion.
Now if that’s what ya got and what ya can afford, I’m not knocking it, but even that is a skewed argument as non OD equipped vehicles are all classic cars/trucks by now and apples to apples, frankly more expensive than older OD equipped vehicles.
It’s not wrong to be ok with driving old iron, I love to as well. But if I’m eyeing up my 10 speed pickup, 5 or 8 speed cars or 6 speed auto diesel or my C10, K20 or CJ5 for a road trip or frankly anything that involves freeway/highway speeds for even commuting guess which ones get left at home?

 

[Grit dog]

Nv4500

Yup, that’s about the least intrusive swap for reliability and simplicity of conversion, afaik.
But in reality most any trans swap, auto or manual in a 4wd will have some fabbing, parts collecting and figuring to be done.
I’m not well read enough to have memorized all the stuff some of the folks here have, spline counts, adapters, the right clutch hardware that works for a manual swap, etc.
There’s not really an easy button and the ultimate intended use of the vehicle figures in to what is the best path forward.

 

[Grit dog]

What I mean by the last sentence is, some folks just want to be able to lower rpm’s some to go putz 55-60 mph down the county or state road and don’t leave within a 50 mile radius of home base most of the time. Where others are driving cross state or cross country on a freeway with an 80mph speed limit and would prefer not to celebrate their next birthday just getting somewhere.
All food for thought in the decision process.

 

[bucket]

I'll just point out that yes newer trucks have overdrive and it is more desirable than non-overdrive and it would be silly to want an non-od trans in a new truck.

But, that's a new truck and cost would be essentially the same either way. With the older truck, you already have the non-od trans and going to overdrive would be a significant investment that you likely won't get much return on.

Now with that said...

If I was choosing between a gear swap or a trans swap, I'd definitely go with a trans swap. The reason being, I'd hate to neuter a truck by swapping in gearsets that will reduce the potential of the truck. With an overdrive trans, you can have your cake and eat it too. Either option has the potential to be very spendy.

 

[Grit dog]

^ @bucket, well said.
Bottom line it’s a consideration of time, money, ability, desired use, end product and a couple other things I’m probably missing.
And 2wd vs 4wd is a factor too.
My old trucks will not likely be in the drive everywhere all the time category, so the ROI on doing ANY major surgery to them to lower rpm’s is basically lost on me.
Thats why we’re all different. I enjoy seeing everyone’s projects and outcomes.

 

[CountKrunk]

Id want to maintain being able to tow 5-10k (prob more like 8k).want to be able to cruise at 70 at 2.5k or so. 4.10 14 bolt full float rear. 2wd.

 

[BigT]

Id want to maintain being able to tow 5-10k (prob more like 8k).want to be able to cruise at 70 at 2.5k or so. 4.10 14 bolt full float rear. 2wd.

I'm right there with you, but mine is 4wd, obviously. Mine is a daily, and primarily used for short distance road driving with small or no loads, for which the current setup is not really a problem. It's also excellent for the occasional off road use. However, I do sometimes (1-3x per year) need to drive a few hours away on 70 mph highways, sometimes with a load on, and my current setup is not really fun for that, which is why I'm considering future options. All great thoughts so far, thanks.

 

[Ricko1966]

I'm right there with you, but mine is 4wd, obviously. Mine is a daily, and primarily used for short distance road driving with small or no loads, for which the current setup is not really a problem. It's also excellent for the occasional off road use. However, I do sometimes (1-3x per year) need to drive a few hours away on 70 mph highways, sometimes with a load on, and my current setup is not really fun for that, which is why I'm considering future options. All great thoughts so far, thanks.

One thing to add to your consideration I don't have my gear ratios memorized,but they'll be close. The th400 has a 1st gear around 2.50 and a top gear at 1.0 to 1 the 700r4 is 3.07 1st, 1.0 3rd like your 400 and a .73 overdrive. What this means to you,with a 700r4 you'"ll have more of a granny 1st to get moving 3rd gear will be the same as you have now, when you go into 4th your going to bring your cruise rpm down. My opinion is that the 700r4 or the 4l80 is going to be a no compromise deal,you get to keep your towing,mudding gear and still cruise on the highway. (4l80 won't have your steep first ) it will be same gearing you have now, until you hit overdrive. If you seldom get on the highway for any distance. I think you'll spend more swapping than you'll save in gas.

 

[DoubleDingo]

I'm right there with you, but mine is 4wd, obviously. Mine is a daily, and primarily used for short distance road driving with small or no loads, for which the current setup is not really a problem. It's also excellent for the occasional off road use. However, I do sometimes (1-3x per year) need to drive a few hours away on 70 mph highways, sometimes with a load on, and my current setup is not really fun for that, which is why I'm considering future options. All great thoughts so far, thanks.

Maybe on those 1-3 times a year rent a truck to do the job and leave your truck alone? Way cheaper and less work, and no wear and tear on it for those longer trips

 

[CountKrunk]

It's nice to have the ability to cruise on the modern interstate.

Going 65 i feel bad haha. Causing 18 wheelers to have to pass me.

 

[DoubleDingo]

It's nice to have the ability to cruise on the modern interstate.

Going 65 i feel bad haha. Causing 18 wheelers to have to pass me.

I don't mind it. Go around, the brick can only go so fast...lol...

 

[Grit dog]

^Absolutely, the above 2 posts are examples of different needs and wants.
And then of course hp/tq vs gearing (trans or final drive). If you got 450hp under the hood, you can tow your 10klbs with ease AND cruise at 75mph at lowish rpm’s with a 3sp auto no OD trans and some tall gears.
Try the same with 200hp and you’re wishing you had the 4.10s or 4.56s when you’re hooked up and cursing the 4.10s and 4.56s when running bobtail down the freeway.
It’s really a matter of setting a budget and then analyzing wants and needs. (Shocking I know…lol)
So back to one of my earlier comments that someone refuted. I think the best way to get all that or at least a significant improvement is just move up to a newer vehicle. There’s millions of 6.0 LS GM 2500 and 3500 trucks that are now largely deprecated out and do everything you could reasonably do with a decent budget plus ride in quiet comfort.
At that point the only downside is the lack of nostalgia factor of doing it in an uncomfortable, loud, cramped old lumber wagon that looks cooler than the other million GMT 800s on the road.

 

[CountKrunk]

^Absolutely, the above 2 posts are examples of different needs and wants.
And then of course hp/tq vs gearing (trans or final drive). If you got 450hp under the hood, you can tow your 10klbs with ease AND cruise at 75mph at lowish rpm’s with a 3sp auto no OD trans and some tall gears.
Try the same with 200hp and you’re wishing you had the 4.10s or 4.56s when you’re hooked up and cursing the 4.10s and 4.56s when running bobtail down the freeway.
It’s really a matter of setting a budget and then analyzing wants and needs. (Shocking I know…lol)
So back to one of my earlier comments that someone refuted. I think the best way to get all that or at least a significant improvement is just move up to a newer vehicle. There’s millions of 6.0 LS GM 2500 and 3500 trucks that are now largely deprecated out and do everything you could reasonably do with a decent budget plus ride in quiet comfort.
At that point the only downside is the lack of nostalgia factor of doing it in an uncomfortable, loud, cramped old lumber wagon that looks cooler than the other million GMT 800s on the road.

Exactly which has me thinking of buying a drivetrain parts beat up old truck that has LS and trans i want in it.