The Stovebolt Site Forums The Parking Lot Big Bolts 2-Ton 5-Speed in a 3/4 or 1-Ton

I recently learned that some 2-Ton 5-Speeds from the '60's have Overdrive. A Clark CL267VO and a Clark 264VO are a couple of examples. I'm wondering if anyone out there knows if one will bolt in to a '67 to '72 Chev/GMC 3/4 Ton or 1 Ton truck?

If it fits with no or very little modification, it sounds like it could be an easy way to get a Heavy Duty Overdrive Trans and for a decent price to boot.

Any info would be appreciated.

Bill

I don't think it would be an easy fix as the frames are totally different so the mounting would be also. The tranny would probably bolt up to the engine but the stick might not work in the cab floor. Those transmissions are pretty heavy compared to a PU tranny. The 2 ton cabs sit higher on the frame too so the floor hump would likely need much alteration.

Someone may have done however as anything is possible if you throw enough time and money at it. An OD 3 speed would work easier if you can find one.

The majority of the old overdrives are now obsolete. If you are lucky enough to find parts they are often expensive. I know some commonly needed parts are not available for many of not all of the old Clark OD transmissions, a friend of mine was recently running one and had several more for spare parts, still could not find enough good stuff to keep it in service, and he is an excellent mechanic and has good luck finding stuff if it's out there.

If you find a good one that fits it's probably worth a try, but may not be a long term OD solution.

Some of the big ones are really quite big. The 5 speed that came with the V12 I owned for a while could have been ordered as an OD, probably weighed about 300 lb.

Grigg

Appreciate the info y'all. Now my next question would be are there any newer 4 or 5-Speeds in the '70's, 80's or 90's that have OD that would work. The newer Small Block and Big Block Chevy V-8 should take the same Bell Housing as the older ones. Also wondering if there are any aluminum ones out there.

I've been trying to find the most simple and cost effecient way to put an overdrive in both my '72 1/2 ton 3-Speed and my '68 1-Ton 4-Speed.

So far (1) the 3-Speed OD only went to '69 and are just about impossible to find, (2) the Tremec Conversion is too non-original for me and way too expensive, (3) the S-10 Conversion is too weak, (4) an aftermarket OD is also way too expensive, (5) an Aux trans would take away my bench and I believe is a lot work and somewhat expensive (altho I would love 2 sticks),(6) a Camaro "World Class" trans is supposed to be stronger, but was told won't work right without a S-10 Tailshaft (This is my best choice yet tho, even tho I get conflicting info on it) and lastly is my new possible choice above.

If anyone knows of any other choices I may have missed just let me know.

Thanks

Bill

You sould be looking for a NV4500 from a '92-'94 Chevy/GMC 3/4 or 1 ton truck. Just saw a couple go for $500-800 on fleabay in the last few months.

I got mine for $800 about a year ago. It has Chevy bellhousing,E-brake drum & electric/hydr Muncie pump mounted on pto. Going to mount to 292 in my '54 3800 some day soon.

Do a NV4500 search, Good luck

p.s. Some people like the newer GM/Dodge Nv4500 for the speedo cable hook-up.

An NV4500 may be your most economical and easy to swap OD choice for your 1 ton, yet it is still not cheap. It is also obsolete, hasn't be made for a number of years, but aftermarket parts are still available in varying qualities.

Others will have info on that swap, and you could do a search for NV4500.

The 1/2 ton may be good with a T5 mix and match combo from a camaro and an S-10.

Grigg

I'll check that out.

Appreciate it, y'all.

Bill

Bill, if you are looking for a modern or different 5 speed overdrive you will find a lot of good info here:
http://www.4btswaps.com/forum/forumdisplay.php?f=22
The discussions are geared to (pun intended) transmissions that work well or easily behind the small Cummins. However, in most cases the same transmissions can be adapted to an ordinary gas engine as well.

Grigg

Thanks Grigg.

I'll read up on it.

Bill

BTW, For a while I thought I had the perfect solution to an overdrive for a 1/2 Ton Chevy/GMC truck, especailly one with the low hump floor like mine has.

Someone was converting Muncie M-21 and M-22 4-Speeds to an OD trans. They were replacing 3rd Gear with a 1 to 1 Gear and 4th Gear was an OD Gear.

Perfect swap with no or just about no modifications on an original 3-Speed truck, again like mine.

Problem is, as it was explained to me, that many people driving in the city would keep it in the 3rd Gear position, which was not originally designed for long term driving and it was wearing out the bearings.

...Idea scrapped.

Wondering if the same bearing wear would happen still if converting a SM420 or SM465 over to an OD? My guess would be yes, but I'm wondering if it's ever been proven either way?

Bill

I'm increasingly convinced the Tremec is the best option if you want to drive it like a car. I know its spendy but there are not a lot of choices.

One you didn't mention is the Corvette 4+3, which is basically a Super T-10 with an automatic overdrive in the tailshaft. It is stout enough for a strong small block in a 1/2-ton pickup, uses a conventional shifter location, is hard to mount and not popular even with the Corvette crowd.

They often replace it with a Tremec.