I've got a '56 F100 with a stock 223ci I-6 and 3-on-the-tree non synchro first gear and 3.92 rear Dana 44. The engine was rebuilt ten years ago and is at this point consuming a gallon of coolant a week but the oil is a-ok. The trans non-synch 1st is annoying and it tops out at 60 all out(I don't feel safe pushin the engine past 3000)


My solution years ago was throw in a late model 300 with a factory mated manual OD trans and this would give me a much more reputable engine, OD trans for little more speed, and no swapping rears.
I've done reading for years never pulling the trigger and now I'm losing patience with my pathetic 223 money pit.
But it sounds to me that all of the OD trans mated to the 300 from the most common era are all week crap and break if you look at them wrong(80-86 in my junkyard; all the 90's trucks have autos--can't have an auto in my truck)
(I read this thread : https://www.ford-trucks.com/forums/1...overdrive.html )

Is this true? If so, Any direct bolt in OD trans for the 300 that can actually handle abuse?

I am actually considering just throwing in a 300 with an NP435(theres one or two at the yard) just in desperation to get my 223 out. But I love my column shift and would hate to go to a floor shift just for another direct-drive final gear.....that wasn't my "plan". (And it sounds like all these trans mount differently so I wouldn't just be able to throw in a OD trans at a later date; once I swap in an NP435, thats basically what I'm stuck with without redoing the whole swap again...)

What's your guys' experience with these OD trans?
Thanks for any advice.

 

(Quote)Is this true? If so, Any direct bolt in OD trans for the 300 that can actually handle abuse?(/quote)
That right there is the issue "abuse"!
This goes for the SROD transmission.
It is used and who know about abuse on the miles it has?
They really were not meant to go in trucks and we all know trucks get abused.
Then there are bushings in the shifter that go bad and that adds to the abuse.

Now there is the M5R2OD trans that seams to hold up better to abuse than the SROD trans as it was used in the 250 trucks and shifts like the SROD I hear. There is a member running one behind a beefed up 302 and loves it.

Now if you are looking for a true work truck trans with OD then a ZF5 is what you want. Thing is hard to find, they all seam to need a rebuild and are $$$$$.

I have a 300 in my F100 and it had a T18 granny first truck transmission but I wanted the granny gear. Trans was shot so found a NP435 and added Advance Adaptors range splitter over drive and so far love it. I don't have a lot of miles on it but now that the truck has AC that will change.
Dave ----

 

I don't know of any overdrive trans that was column shift. It will have to be floor shift unless you stick with a 3 speed.

 

I had an srod behind a 300 1985 model, shifted good and everything. I miss the overdrive and ability to go down to 3rd for just a bit more rpm. Drove it pretty hard and never had a problem I doubt a 223 will break it. The mazda 5 speed shifts pretty good and is a good choice for an inline 6 but then there's the hydraulic clutch swap.

Maybe a rear gear change would be enough of an rpm drop?

 

If driven with care, the manual O.D. transmission [behind a 4.9L/300 engine] gives very good service and gas mileage.

I have driven a 1986 F150 with that combination for 215K miles.

My son has a 1984 with the same drive train and his truck has approximately 258K miles.

Both shift smoothly and have no strange noises.

 

There are also "non-Ford" options (as if Mazda or ZF are Ford). NV-3550, AX15, NV4500 are all 5 speed overdrives that people put behind small block Fords pretty regularly (I have a NV3550 behind the 302 in my '71 Bronco)

 

The Mazda & ZF come in a Ford bell housing not so sure on the NV-3550, AX15, NV4500 and think most you find are for 4x4.
I wound not go with the AX15 as my son has one in a Jeep and it has issues.

But it is up to the OP to check out each transmission listed on what might work best for him.
I can tell you if I did not build my truck as a back up to pull my 20' open deck car trailer, why the granny first, I would go with the Mazda M5R2 I think it is.
Dave ----

 

The iron cased 4 speed OD isn't prone to breakage like the aluminum ones. Still OD is "weak" so they say. The gap from 2nd to 3rd is bad.

I think the NV-3550 might be a winner in this case.

 

The 5spd in the Ford half ton pickups (and light duty 3/4 ton pickups) between 1988-1996 (and beyond) was the M5OD-R2. I have one of these transmissions in my 2wd '84 F150 with a 300HP 302 and I love it. Now, unfortunately this transmission has gotten a bit of a bad reputation over the years as being "weak". Personally, I think the bad reputation comes from guys buying old trucks and 4 wheeling them...lift kits, big tires, off-roading, etc and stuff breaks. Ford did sell thousands and thousands of trucks with this transmission, and the stories you don't hear are that lots of guys put hundreds of thousands of trouble tree miles on them. I know lots of guys that used them in plow trucks. The good news doesn't travel quite as well as the bad news does.

I guess the big question is what are you referring to by needing a transmission that can handle abuse?

 

I totally forgot about the T5 and better yet WC T5 out of older Mustangs.
You would need to come up with a shifter stick as the car one I think would be to short but think it could take what your six can throw at it.
Dave ----

 

Thank you for the input everyone. Abuse in my def is simply daily driver and using the truck up to its 5000 lbs GVWR(Old half tons were wimps, the 80's trucks are like 6100). Obviously hauling loads would not be done up hills at 70mph in 5th gear.
I just need to make sure I'm spending time swapping something that won't break because I put some bags of cement and plywood in the bed. But it sounds like I'm taking a gamble by using untried junkyard stuff...

If I got a 300 out of an 86 F150, will it immediately bolt up to an OD trans from 1990?

What years did they use the computer carburetors? A truck from 86 in the junkyard didn't appear to have any wires sticking out of it like a computer controlled Quadrajet that I'm more familiar with, (and GM was using computer Quads by the early 80's)

 

The M5OD trans is plenty good in normal use and they should be easy to find used and mate to a 300 if you find it separate. As with anything used, prior use is suspect unless you know who had it, so buyer beware.

On the carbs, I know the feedback carb was used in '85 because I have one. It's not that hard to replace and also put on a Duraspark distributor to make things "right" as it were. Read up on them, plenty of threads here on that subject.

 

Any transmission / bell housing that will bolt to a small block, that what the 300 six uses, will work.
I believe the feed back system came out in 83 but don't let that or even a EFI 300 six scare you off as you can pop a non-feed back carb & dist. (DSII or HEI) on it.
EFI motor would need intake manifold and run an electric fuel pump, no opening in block for it.

On the transmission when you start getting into the 90's they no longer have a hole in the case for a speedo cable but if for a SB will still work just no speedo.
Also think some where mid 80's they went to a juice clutch so you would need to work that into your truck.

So true.
I was lucky the NP435 I picked up used, believe from an 85 PU that had a juice clutch as the slave cyl bracket was on the bell housing, was good.
3rd gear has a little grind every now a then but 99.9% better that the old T18 I pulled out and for a few hundred dollars I am happy.
As said I also installed Advance Adaptor's over drive unit, I can split all gears so I have 8 forward & 2 reverse not that I use them all the time.
So far I am happy with the combo and the 2.47 rear gear and 235 / 75 / R15 tires. 65 MPH I am turning 1700 RPM.
Dave ----

 

There is no integral bellhousing on the NV-3550, AX15 or NV4500. So you need the (separate) Ford bell as well as the trans. There are adapters available to put them together.

The NV3550 and AX15 might only be available in 4WD versions, I'm not sure. But there are definitely 2WD NV4500s.

And I'm not saying that the Mazda trans isn't the best choice for the OP. Just pointing out other options.

Does the fuel pump attach to the block on a 300? My 302 is from an '88 F-150 and wouldn't take a mechanical fuel pump. But when I replaced the F-150 serpentine belt system with a V-belt accessory drive for an early Bronco I had to switch the water pump and timing cover. And on the 302 the fual pump attaches to the timing cover. The newer engine even had the eccentric to drive the fuel pump. But that's a 302, not a 300, so this might not apply at all.

 

NV3550 and AX15 are available in 2wd models that were used in the Dodge Dakota and 2wd variant Jeeps. The R154 is similar to the NV3550 and AX15 and are found in Toyota Supras.

Reference links for reading:
https://www.novak-adapt.com/knowledg...issions/manual
https://www.novak-adapt.com/catalog/...rd/windsor-v8/

I have a T98 in my '56 F100 and have been researching transmission options. I ended up swapping to a 2.75 ratio in the 9" rear end, and picked up a close ratio T19 four speed to be swapped in soon. First gear is a very usable 4:1, 1:1 fourth gear with the 2.75 rear makes for a good highway RPM also.