1985 F350 Transmission Options

Hi Everyone,

I've been reading and researching transmission swap options for my 1985 F350. So far I'm smart enough to know the options, but dumb enough to buy a M5R2 listed as a ZF5 from FB marketplace (working on getting a refund..).

Reading up on the M5R2 though, I'm thinking it might actually be a good option.  This will be a daily driver truck for my boys, maybe some LIGHT trails, maybe some LIGHT hauling.  We're learning together as we go, putting a new engine in it, fixing things, and in general having a lot of fun.

My main requirement for the transmission is drivability and ease of shifting.  It currently has a T-19, which is the opposite of that.

The drivetrain is a 351w (which we're rebuilding as a mild stroker), T-19, and NP205.  It's a 4x4 on 35" tires.  I have to believe that they'll pop the clutch to try and spin the tires and do other teenage things, so whatever we put in does need to be durable.

I'm worried about availability of the ZF5 for SBFs too.  They're hard to find and EXPENSIVE to rebuild, which won't get any better as time goes by.  You can't throw a stone without hitting an M5R2.

If I understand correctly there's clearance issues with the NP205 that twin sticking can solve, and possible a spacer because the output shaft on some M5R2 years is too long for the NP205.

So that's where I'm at.  Can anyone offer hands on advice?

Thanks!

BabeTheBlueOx wrote

So far I'm smart enough to know the options, but dumb enough to buy a M5R2 listed as a ZF5 from FB marketplace (working on getting a refund..).

Funny, but that's exactly how I bought the M5OD for my first swap. The seller had it listed as a ZF5, but I recognized it as the M5OD that I was looking for. The issue was, the guy pulled the engine and trans from a 1991 F250 2wd, and he didn't know that an F250 could have an M5OD, so he assumed it was a ZF5. Anyway...that story had a happy ending I guess.

The SBF 4x4 ZF5's are really hard to find, and a lot of the times they've been worked hard and are well worn.

I'm a big fan of the M5OD, but it's not a heavy duty trans, and was never offered behind the 351w (although it will certainly fit just fine). It's a nice shifting transmission, and the gear spreads are nice, and they're easy to find. The downside is that the M5OD has a bad reputation for being a "weak" transmission.
I personally don't think they're as weak as everybody says they are, but it is clearly a 1/2 ton transmission (and did make it into a few light duty 3/4 ton trucks). Problem is...the oldest M5OD's are now closing in on 35 years old, and they're well worn....lifted trucks with big tires and tall gears make life very hard for a tired M5OD. I know guys that plowed snow with M5OD trucks, but that was back in the 90's when they were still fairly new.

I had two M5OD's, and they worked well for me, but I didn't really abuse them either. I'm just a cruiser;).

I don't think I'd put and old one in a 351w F350 4x4 that might see any abuse, or heavy hauling, or towing, etc. If it's just going to be cruising and hauling it's own weight, then it would be fine.

My 2 cents worth;).

Welcome!  Glad you joined.  

But you may have missed the email that Scott sent you asking you to go to the New Members Start Here folder, read the guidelines, and then post an introduction there.  We ask that because the guidelines are posted there and since we hold everyone to them we want everyone to have read them.

Don't worry, lots of people have missed their email so we don't get too excited when the next person does.  But please assure us that you've read the guidelines?

You don't need to look only at "Ford" transmissions (as if ZF and Mazda were owned by Ford).  The NV4500 (comparable in strength to the ZF) and NV3550 (comparable to the Mazda) don't have integral bellhousings.  If you get a Ford bellhousing you can get adapters to attach the NV trannies.  Tremec is also now selling aftermarket trannies.  I'm not sure what needs to be done to adapt them to a 351W, but I bet Tremec does.  I've heard of people putting them behind a built Cummins, and Tremec has a big presence in the hot rod world.  So I'd guess they's shift pretty well while being plenty strong.

Rembrant wrote

I had two M5OD's, and they worked well for me, but I didn't really abuse them either. I'm just a cruiser;).

I don't think I'd put and old one in a 351w F350 4x4 that might see any abuse, or heavy hauling, or towing, etc. If it's just going to be cruising and hauling it's own weight, then it would be fine.

Thanks for the experience and advice. This is going to be a cruiser.. I'm thinking more and more that the M5OD-R2 is a good choice for it.  And not that I want to be replacing transmissions at any regular interval, but I could go through quite a few of these for what a ZF5 goes for.

Gary Lewis wrote

But you may have missed the email that Scott sent you asking you to go to the New Members Start Here folder, read the guidelines, and then post an introduction there.

Done!  Thanks for the reminder.

I have a ZF5 behind my 460 and I can say they are expensive to repair and shift like a truck - slowly.  If you push the shifting you'll damage the synchros, and that is 'spensive.

So for a cruiser the M5OD might be a good one instead.

Rembrant wrote

I'm a big fan of the M5OD, but it's not a heavy duty trans, and was never offered behind the 351w (although it will certainly fit just fine). It's a nice shifting transmission, and the gear spreads are nice, and they're easy to find.

Do you know if I need to get a spacer plate to go between the NP205 and M5OD-R2?  I'm seeing conflicting information on the interwebs about the M5 output shaft being too long.  

If I may need one, I'd rather find it and have it on hand so I'm not twiddling my thumbs for a week with the truck un-drivable.

I mean, something will happen to make it sit for a week anyway, but..

I’m going to play devil’s advocate perhaps?

I could be mistaken, but I do not believe that the NP205 ever came in a bullnose era truck. If your transfer case is a swap, do you know for sure that the transmission is a T19 from 1985?

The reason I ask is because I’ve owned and driven quite a few old Ford PU’s and my T19 is the smoothest, nicest-shifting, car-like transmission of all that I have dealt with. I recently had the linkage pivot break and I was able to drive it by starting it in gear and floating gears 1-4 without clutch (even downshifting). I realize everyone’s specimen is different, but you might consider rebuilding your current transmission if it is in fact the original T19 (or find a good T19).

The small block ZF and M5OD are both different in length than the Borg Warner transmissions, and will require different length driveshafts. The NP205 is different in length than the ZF/M5OD era transfer cases, so this combination will put you into custom driveshaft territory, or you will need the transfer case and driveshafts to go with the transmission you buy (and the cab/bed length of the donor must match yours of course). This is just a wordy way of saying it is going to be a more expensive swap than just a transmission.

Anything is possible with enough $ and effort, but if overdrive is not your primary motive, I would reconsider a good/rebuilt 4-speed. I am putting a ZF in my 6.9 IDI truck because I need the overdrive, but the T19 (now lives in my 300 six F150) shifts nicer than the ZF’s I’ve driven.

BabeTheBlueOx wrote

Do you know if I need to get a spacer plate to go between the NP205 and M5OD-R2?  I'm seeing conflicting information on the interwebs about the M5 output shaft being too long.  

If I may need one, I'd rather find it and have it on hand so I'm not twiddling my thumbs for a week with the truck un-drivable.

I mean, something will happen to make it sit for a week anyway, but..

I'm not much help with the 4x4 stuff unfortunately, but one of the other guys may be able to assist. I did two M5OD 5spd swaps. The first one was 2wd, and the second was not really a transmission swap...I put a 1980 Bullnose body on a 1995 F150 4x4 chassis that already had the M5OD and I believe a BW1356 transfer case, or whatever the factory unit was at the time. So in this case I swapped in hydraulic clutch and the transmission/transfer case shifters, but the transfer case installation was a non-issue for me.

I did at one time bolt up a transfer case and M5OD trans, but the transfer case was out of a 1985 F150 4x4, which would have been what, an NP208? I know it bolted on to the M5OD just fine. The NP205, I'm not sure.

Right, the NP205 never came in a Bullnose.  And you are right, Jonathan, that combo is going to be expensive.

I dont think a T19 / T18 / NP435 are bad transmissions for a cruiser.
It's not like you are going to be speed shifting any top loader (ZF or M5OD) transmission.

BTW I run a NP435 in my 4x2 81 F100 Flare Side cruiser and like it.
Besides with the granny first it goes nice cruising the parking lots LOL
Dave ----

Ford F834 wrote

I’m going to play devil’s advocate perhaps?

I could be mistaken, but I do not believe that the NP205 ever came in a bullnose era truck. If your transfer case is a swap, do you know for sure that the transmission is a T19 from 1985?

Shoot.  

Thank you for playing devil's advocate. It's a T-18, non-synchro'd, LOW 1st gear. And I knew that. I'm not sure at what point I started thinking it was a T-19. I'm 100% sure it's an NP205, I pulled it out and rebuilt it according to a great youtube video series because it was leaking transmission fluid though the in/output shaft seals like a hose.

OD is a nice-to-have, a "usable" 1st gear is a nice-to-have, and a syncro'd 1st gear would be nice-to-have.

It's really the ease of shifting that's the big dea. Your description of a T-19 is the polar opposite of what this T-18 is like. I've been driving manuals my whole life, and sometimes it takes me so long to get it into 3rd or 4th that I have to abandon the effort and speed up again in a lower gear.

It sounds like you're thinking that the transmission might be old, tired, and/or broken?

Gary Lewis wrote

Right, the NP205 never came in a Bullnose.  And you are right, Jonathan, that combo is going to be expensive.

Avoiding expensive is a "must have".

A quick google search says that T-19's can have a 4.02 1st gear ratio, which would be less severe than the 6.32 ratio on the T-18.  And there seems to be a lot of them out there for a reasonable price.

Our calculator (Documentation/Driveline/Calculators) has the ratios built in for all of the transmissions these trucks came with as well as several more.  And Ford T19's did come with a 4.02 first gear - in the diesel.  But behind a 460 they came with a 5.11 first gear.  The diesel tranny is the "close-ratio" one and has completely different ratios than the wide-ratio for the 460's.  You might ask Jonathan what he thinks about using the close-ratio T19 behind a gasser.

As for the NP205, I'm not doubting you have one.  I'm just saying the truck didn't come with it - at least Ford's documentation says it didn't.  You can see the Master Parts Catalog's information of transfer case applications at Documentation/Driveline/Transfer Cases.

And, by the way, the calculator has the t-case gear ratios in it as well.

The calculator is great - thanks for pointing it out.

I appreciate the NP205 information, it's invaluable to know what's original and what's not before I start trying to fix things and order parts.  I've gotten burned a few times already with that scenario already.

Your shifting experience is due to wear and damage. Most likely shifting forks and synchronizers. The shifter cane is hardened steel, but even minor burrs or wear can drastically affect how it shifts. I tried to switch shifter canes on my T19 for a taller type with a threaded knob. The tip on the donor cane looked visually perfect, but the truck wouldn’t shift into 3rd at all. Upon closer inspection I found some extremely small defects and filed them with a sharpening stone. It would then shift into all gears but not as smoothly as the original shift cane so I put it back. There is also a hardened locator pin in the shift tower that prevents the cane from rotating. If this pin is worn or loose it can make shifting nearly impossible. Since the shifter is often removed when servicing the clutch or other maintenance, this pin has a tendency to be misplaced and replaced with something else that is softer or the wrong size. A sawed off drill bit shank is a common substitute. If you have a Borg Warner, check this pin and it’s hole in the shift tower casting. Wear or play will make it shift like crap even if the shift forks and synchro’s are still in good shape.

The T19 that I like so much came out of my 86 F350 diesel. It has the 4.02 first gear, and I drive it like a true 4 speed, not a 3 speed plus a crawl gear. For my F150 with 3.00 axle gears it is perfect. 1st is just right to start out in with 235/85 R16 tires and the close ratios are just right for the low revving straight six. Dropping from 4th to 3rd on a grade is right where you need it, not an engine screaming defeat that slows you down even more. When it was in the diesel F350 it was paired with 4.10 gears. When loaded heavy they were just right. When driving empty it was a tad annoying. It wasn’t geared low enough for me to skip 1st, and I was already reaching for 3rd by the time I got through an intersection in city traffic, and it desperately needed overdrive. Your axle gears and tire size will have a lot to do with which T19 suits your needs. That and the power band of your engine. My experience has been with a 6.9 diesel and 300 straight six, both with very low rpm torque peaks.

Thanks, Jonathan. I knew you’d know.

Thank you all, this is extremely helpful!

I'm going to keep my eyes open for a 4.02 T19.  They're not as readily available as I first thought, but I'm sure one will come up eventually.

The engine going in will be built for low-end torque, so that might just be the ticket.

Good luck with the hunt.  Something will surely turn up.  

BabeTheBlueOx wrote

Thank you all, this is extremely helpful!

I'm going to keep my eyes open for a 4.02 T19.  They're not as readily available as I first thought, but I'm sure one will come up eventually.

The engine going in will be built for low-end torque, so that might just be the ticket.

I am building a 6 cyl truck for a similar purpose and I went with a T19 as well, except I bought the 5.11 version. A quick and easy way to identify a T19 when it's on a truck is toploading, cast iron top and bottom, and dual PTO covers. If I remember correctly you can't identify the version with casting numbers but you can find them with the application chart. According to Novak's webpage on the T19, you are looking for a T19A.

When I bought mine I went through car-part.com and had junkyards send me pictures of the casting numbers until I got a bite. That way you can also find one with the big block bellhousing "for free" and sell it on ebay for big bucks. All the parts I needed for the rebuild were available but definitely not easy to find.

Not all diesels came with the 4.02 version. If that’s the one you really want, be sure to put it in gear and count rotations before buying.

Note that the NP205 only has a low range ratio of 1.96:1, which is rather mild as transfer cases go. Paired with a 4.02 version T19 your first gear is 7.88:1. This is still more stout than a 2wd with a “granny” 4 speed, but might not be low enough for some 4x4 uses, especially if you have tall-ish axle gearing and big tires. Just something to be aware of since your 4 low range isn’t as low as the chain driven transfer cases.