Option for budget manual transmission upgrade
 

So my 18 yr old son joined the addiction this weekend. Went and bought himself a 1972 C20 with a 350/SM465. We were told that 3rd in the trans is junk (works at slow speeds but we haven't had it up to speed yet though). So since he already wanted overdeive, he is looking into his option to upgrade to something with an overdrive. We are trying to keep it as budget friendly as possible, but also don't want to put something in that he is going to want to replace in 4 years.

As for the motor, starts up and runs. But she is leaving a nice smoke screen behind it. So lucky for him I have a 402 I built and ran for a couple years sitting in the garage. So whatever trans he decides to go to is getting the 402 in front of it.

Re: Option for budget manual transmission upgrade
 

It kind of depends on what he will be using the truck for. Will he be using it to tow anything or haul heavier loads? Does he have a lead foot or is he a pretty sensible driver?

Here is a pretty comprehensive thread on installing 5 speed transmissions:

http://67-72chevytrucks.com/vboard/s...d.php?t=313954

And the install of the NV4500 in my '72 Chevy Dually:

https://www.67-72chevytrucks.com/vbo...d.php?t=673588

This is a beefy 5 speed overdrive transmission for working type trucks and trucks with more horse power.
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Re: Option for budget manual transmission upgrade
 

Were about to do a nv3500 in our squarebody in place of a 465.
Fortunately It had a hydraulic clutch already

Re: Option for budget manual transmission upgrade
 

His plan is to converting it to a shortbed, convert it to 5-lug and then do a static drop with springs and spindles. I don't think towing is in his plans.

Thanks for the links. I had been looking at the NV4500, and now looking at the T5. Any advantages disadvantages to either?

Re: Option for budget manual transmission upgrade
 

T5 is a fairly light duty trans, and you ought not bang shift them by the sound of it. If he is only ever going to use the truck as a cruiser, it'd probably be just fine.

I have partially swapped in an NV4500 into my '72 C3500. I have driven it 2 miles to test and that's it. My unit shifts very nice, but most modern car folks say they are just another clunky truck trans. They weight the same as the SM465 that came out: ~200lbs

They have their ghosts: 5th gear backs out and causes trouble, but this is mainly a "diesel NV4500" thing, there is no prominent easy fix.
going rate for them when I bought one a few years back was $1100 in SoCal. Saw one for $1k at a swap once, never again.



It was nerve wracking to drill the holes in order to mount the 4500 using "LocDoc"s method, but I got it done, good enough anyways. Knowing what I know now, I would swap every future Chevy truck I own with an NV4500. Can't wait to find the time (lol) to finish the truck and get it on the road....

Re: Option for budget manual transmission upgrade
 

What's the budget? To start with of course. We all know how these things end up. :lol:

Re: Option for budget manual transmission upgrade
 

I'm not well versed in 5 speed transmissions but the only thing I can tell you is that he is not going to speed shift the NV4500.... :)
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Re: Option for budget manual transmission upgrade
 

NV4500 is tough but not a sporty trans which is what it sounds like this build is trying for.

Re: Option for budget manual transmission upgrade
 

I think a t-5 will not be a durable trans behind a big block . The T-5 is rated to a max of 300 lb-ft of torque. I would look at the TKX it’s under 3k right now for a new unit . With all the planned work I wouldn’t cheap out on the drivetrain

Re: Option for budget manual transmission upgrade
 

I was hoping he didn't need to spend more then $500 for the trans. But that seems to be unrealistic at this point. So I would say if he can stay under $1000 he would be good.

Re: Option for budget manual transmission upgrade
 

I agree. I would not put a T5 behind a big block. You WILL break it.

Re: Option for budget manual transmission upgrade
 

Around these parts, a SM465 is the only thing left over when the rest of the truck is junked.
I went to the Portland Swap Meet once you and I could have filled the back of a dump truck with them.
The cheapest option is to replace it with used. $75 buck should do.
However, if the truck is driven a lot, an overdrive would be a great addition.
Have you considered retrofitting an automatic?
The manual may keep his buddies from driving it if it! :)

Re: Option for budget manual transmission upgrade
 

Going back to a SM465 is always an option but he has plans for some road trips where the overdrive would REALLY come in handy.

I keep trying to steer him towards a automatic, but at 18 yrs old, manually shifting the gears is high on his requirement list. Specifically hunted for a manual truck when buying.

Re: Option for budget manual transmission upgrade
 

Unless it is going to be driven a LOT I would just stay with the SM465. It takes a lot of miles of driving before the overdrive pays for itself if ever.

Re: Option for budget manual transmission upgrade
 

Maybe I missed it, but what is the rear gear ratio and what rear-end is installed? Changing all the bits forward will only slightly help the rpms, but she still gonna scream going down the freeway.

Re: Option for budget manual transmission upgrade
 

Rear gear ratio is TBD. He is on the hunt for a 12 bolt out of a C10 so he can swap it over to 5-lug easily.

Re: Option for budget manual transmission upgrade
 

Another vote for keeping the SM465 and changing gear ratio in the rear. My C20 has 4.11s and driving at highway speeds without overdrive doesn't bother me. And that's even with little to no cab/hood insulation. Lower the ratio and add some insulation and it would really wouldn't matter.

As was mentioned the 465's are plentiful so you can easily (and cheaply) buy a different one if yours is trashed. And they're also pretty easy to rebuild, it was the first transmission I did myself.

I was previously in the market for an NV4500 to put in a different truck and with today's prices I bet it would've been $2k+ including all of the other parts needed.

Re: Option for budget manual transmission upgrade
 

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I don't care what rear end you have in it, I can guarantee you the truck will be a lot more fun to drive with a 5 speed in it compared to an SM465, This is experience talking, and a lot of years of it.....

If you want a pretty tough factory 5 speed manual don't rule out the Jeep AX15 or the Toyota Supra Turbo R154 5 speeds.(basically the same trans) There is an adapter kit available to bolt them up to the Chevy bell housings and they are a pretty stout manual 5 speed. The adapter is a little pricey but it is milled, and the kit comes with an input shaft bearing retainer and mounting hardware.

https://www.novak-adapt.com/catalog/...it-gmax15.html

I bought the kit and I have a '91 Jeep 2WD AX15 trans installed in my '34 Ford Coupe behind a Chevy 377ci engine and haven't had any problems with it..

If you are replacing an SM465 and are using the above adapter you will need a bell housing adapter ring, get it from here:

https://www.advanceadapters.com/5403

LockDoc
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Re: Option for budget manual transmission upgrade
 

Engine upgrade, trans upgrade, rear end upgrade, frame cutting and a suspension upgrade. Seems like a pretty aggressive and expensive list of upgrades for an 18 year old to have a C10 when all is said and done. Not dumping on his parade, but seems like he might be better off making what he has pretty, selling it and using that cash towards something closer to the wish list. These trucks with a good paintjob are selling for some good cash.

Re: Option for budget manual transmission upgrade
 

No dumping on the parade. I appreciate the feed back.

It is a big list, but isn't his first rodeo. He did just as much work building our 69 Suburban as I did. Sand blasted the frame, rebuild the front suspension, swapping the rear end, helping with the LS swap, reworkingt/pinning the ls harness, amoung other things. So the work shouldn't be an issue. Plus, the work gets him out of his room away from the TV/Computer.

As for money. Kid has had a job for 2 and hasn't spent any of that money as he was saving up for a project. With that said still trying to keep it a budget build as much as possible. Based on this discussion, and then whatever rearened/gears he ends up with, the SM465 might be the solution (shoot maybe will will rebuild this one and he can learn more skills). I think his ultimate goal is to build this one, learn some more skills and then maybe sell it to step up to something else. Who knows, maybe he'll build this one, make it his "shop truck" and then find something else to build.

I do appreciate everyone's input on this.

Re: Option for budget manual transmission upgrade
 

Maybe find a good used Gearvendors unit ?
https://gearvendors.com/cg2wdt.html

Re: Option for budget manual transmission upgrade
 

One can only get so much change from a differential gear replacement.
A 10% to 15% change will be noticeable, and a 20% to 30% change will be significant.

The motor speed with 4.11 gears and 30-inch tires is 2836 rpm.
The motor speed with 3.08 gears and 30-inch tires is 2125 rpm.
This is a 25% decrease in RPM.

However, you have lost all torque multiplication advantages, of gearing, in the process.
With an overdrive, you get a lower first gear and a 30% reduction in motor speed.
You can have your cake and eat it too.
It all depends on your wallet and skill set.
Cheers.

Re: Option for budget manual transmission upgrade
 

The AR5 may be another option. Not rated for big power but they are living ok in moderate power aftermarket setups.

Re: Option for budget manual transmission upgrade
 

No one has mentioned the GM 883 transmission. I know it's only 3 speed with an overdrive but the torque of the BBC would cover for some of its short comings. It would fit the budget and check some of the boxes. Not a common transmission in GM'S but it would be a low buck option if you can find one.

https://www.classicjunkyard.com/new_process_a833.htm

Re: Option for budget manual transmission upgrade
 

LOL I would pay anyone $100 cash to come to my towns junyards and find me even ONE of these trans; I'll buy 'em lunch on top of that if they can get their slimey hands on it for only $75 :lol:


EDIT: copyright at bottom of page says 2008, that might have something to do with it.