Dana 44

Ahh, the venerable Dana 44! Cool, goes well w/the 9" rear, why did they go to the eight inch? to save money?
Pm on zf build should B there. Lemmie no if not.
cf
BTW: most don't like the TTB but it too can B built!

 

I'll give you the point on durability. But have you ever driven one of these with the 4 speed OD? They are helpless between 35-50 mph. 2nd is too short and 3rd is too tall. Add a little hill, a little load and a curve or two and it takes all the fun out of your day.

ymmv.

 

Its a good durable tranny but I agree with you. It does not like hills at all!! Or a strong head wind. Shifting between second and third theres a big gap.

 

Have you compared gear ratios? Are you planning/willing to change your axle ratios?

SROD ratios:
Ratio #1: 3.01 1st, 1.78 2nd, 1.00 3rd, 0.79 OD and 3.01 Rev. (3.8 spread)
Ratio #2: 3.25 1st, 1.92 2nd, 1.00 3rd, 0.78 OD and 3.25 Rev. (4.16 spread)

ZF ratios:
5.72 1st, 2.94 2nd, 1.61 3rd, 1 4th, .76 OD (3.86 spread)

M5ODR2 ratios:
3.91 1st, 2.24 2nd, 1.49 3rd, 1.00 4th, 0.80 OD (4.88 spread)

T18 "granny low 4spd" ratios:
6.32 1st, 3.09 2nd, 1.69 3rd, 1.00 4th (3.09 spread)

There's two things you have to look at: one is the gear spread across normal driving gears, and whether you're willing to re-gear your axles.

If you're not hauling & using the granny gear, the only advantage of a ZF over your SROD is a different 3rd gear placement, unless you're willing to re-gear your axles to the 3.25-3.50 range.

M5OD is quite wide, but lemme tell you, I've driven two (30Kmi, and 100K mi), and there's a valley between 1&2, and OD is just a small change from 4th. It's obnoxious. Same regearing comments about the ZF apply- you'd have to regear this one, otherwise you're loosing some of your OD. There's also the reliability aspect- leaking oil plugs and worn/bent shift forks are essentially guaranteed by 100K mi, and rebuilt units are not cheap. Many shift like "an axle handle in a bucket of bolts". Neither of mine would engage 1st in cold weather, and both had a noisy 3rd gear. I believe it's an old Mazda design (read: little 4cyl) that was "supersized" for the F150/Bronco/Explorer, and never did well.

There's many threads in the 87-96 forums about replacing an M5OD with a ZF, but not many actually do it, because smallblock-bellhousing ZF units are expensive and rare.

If you're willing to regear, the 300-6, granny-low 4spd and 3.00 axles (3.25 if you have bigger tires) is a classic combination. It's a long time between shifts, but it's very smooth and suits the 300 well. Your .8 OD SROD and 3.73 gears have almost the same final drive ratio (in OD) as the granny-low and 3.00 axles.

Another option, if you're wiling to spend $300-800 on adapters and not have to regear, is the NV45005-speed transmissions out of Chevy & Dodge trucks.
NV4500 Transmission Bellhousing Adapter Plate | NV4500 This site uses Dodge transmissions, which gets you a better 3rd and a better OD, and they're readily available. As you can see from the link, NV4500 is a common swap in all kinds of trucks- Jeeps, Yotas, Fords and Chevy's alike.

Dodge NV4500 ratios:
5.61 1st, 3.04 2nd, 1.67 3rd, 1.00 4th, .73 OD

Or, you could just wind your truck out another 500RPM in 2nd gear to avoid bogging/lugging in 3rd.

 

BB88,
Thank you! Now we have some REAL info - the ratios. That's the straight dope. For the NV 4500 the dodge is suggested as an easier swap. Some like the NV (what is it?) 3550 for "smother more car like shifting" (again, the dodge is suggested).
One piece of info - some of us like the ZF for the L/R 2 PTO "ports" AND lower over all weight.

 

If you need PTO ports, and the ZF has 'em, then it's an excellent solution.

NV3550 ratios:
4.01 1st, 2.33 2nd, 1.39 3rd, 1.00 4th, .78 OD
(rated for 7800 GVW, 300ft-lbs).
Used in Jeep Wrangler/Cherokee since 2000.


NV3550 is a wide "truck" tranny, but with good gear spacings. 1st is going to feel "steep", but it's got progressively smaller smaller spacings, so it'll be nice. If you regear, you could have a deep overdrive (1700RPM@60 w/ 3.25 gears, 1550RPM with 3.00 gears)

Novak has a SBF/NV3550 adapter for $343.
Adapting Ford Engines to the Jeep NV3550 Transmission

Divide a gear by the next higher gear, and you can get "relative" spacings- even spacings means your RPM range in any gear will always be the same. Progressively smaller spacings are very smooth-driving. Anything much above 1.6 spacing is a "wide" shift. 1.3 is getting to be "close ratio" car gearing. If it's evenly wide like a T18 (1.82 and 1.69, 2-3 and 3-4) you have to rev up with every shift, and it doesn't seem intrusive. It's when the ratio spacing is erratic like the M5OD, that driving gets obnoxious.

Look at your final-drive ratio in each gear, too (gear ratio x axle ratio) (tire size factors in too, but let's assume "stock" tires). "starting off" final drive ratios should be 9:1 or higher. 10:1 or 11:1 are "performance". My F100 is 9:1 with the T18 & 3.00 axle, but the 300 has the torque to do it. Your SROD & 3.73 is 11.2:1 or 12:1, depending. My previous F150 (300, 3.55 axle, M5OD) was 14:1, and that was way to steep for a daily driver. 1st gear was a short jerk, just enough to wind up the suspension tight, before you got to the 2nd, which seemed LONG by comparison. You'll have an even worse time with the M5/NV3550 with your 3.73 gears unless you run big tires.

I wouldn't go any lower than 9:1 final drive ratio in 1st/takeoff gear with your 300. In fact, stay north of 10:1. My wife's Impala has a 2.92 1st with 2.86 "MPG" axle, for a 1st gear final drive of 8.35, and it can't get out of it's own way! 1-2 shift is usually at 25mph. The 9:1 in my F100 is usually OK, but if there's any sort of hill, I have to use granny1st (19:1 final) to get moving- now that's a wide shift!

All my calculations are based on the factory 24" tires on my truck. Circumference is linear with diameter, and taller tires equals a "shorter" final drive ratio. So if you have 30" tires (measure from the center of the wheel hub to the ground and double it), then for the same axle/tranny combination, your final drive ratios are 24/30 smaller than mine because you have larger tires. For example, assume 24" diameter tires are baseline, and that we both have 3.01 SROD & 3.73 axles- only you upgraded to 30" tires. My "starting" ratio would be 11.23, but yours would be (24/30)*11.23=8.98, which is a big difference. All my final-drive ratio recommendations are based on 24" 'factory' tires. If you do have 30" tires, then whatever ratios I recommend, you need (30/24)=1.25 times as much ratio to get the same acceleration and shift points.

I did a lot of research when I had my M5OD F150 about what to swap it with. I decided on a T18 & 3.08 axle. Unfortunately, that truck got totalled by a moron driver before I could do anything with it. If I'd known about the NV3550, I probably would have chosen that.

What diameter tires do you run?

 

a deep overdrive

Now, that's what I'm lookin 4 - 2,000RPMs or below on the hwy (55+mph).


Look at your final-drive ratio in each gear, too (gear ratio x axle ratio) (tire size factors in too...

NOW my FTE membership is payin off! It's alot of factors, but must be calculated in for accurate choices.

Hope U got all of this Coolguy!

Final Q ("what sz tires do U run" is where I start all calculations) - 33" W/me.

 

Do you have a tachometer on your truck? With 33s you're already running a deep overdrive! Your 33/3.73 combo is like a 2.73 "mpg" axle on a "factory" truck, and you have OD on top of it. Your 60mph cruise RPM is already in the 1500-1600 range. Pick one of the "wide" ratio trannys- your 3.25 (max) 1st gear ratio in your SROD is 8.8:1 1st gear, which is on the short side. You must have to slip the clutch pretty good on hills.

I'd look real hard at that NV3550- that 4.01:1 1st gear with your "2.73" axle/tire combo would equivalent to 10.8:1 "factory", and that's "just right".

NV3550, and let us know how it goes! The M5OD people would love you for some swap tech...

 

I've got 33x12.50's on my truck. 60mph @2000rpms actually about 67 according to my gps. Which I would say is pretty close.

 

my gps

What model? what 's it cost?

I got 411 rear gear/projected 33" tire and having a math hassle with the ZF...I can't project what would work best. I'm closer to all-off-road than all-on-road, altho this lill' bob tail Does need to get to each job "over the road", have a long trip ( i.5 hr to 5 hr) now n then, haul a boat over the rd 2 X a yr. (1/2 hr).

So my only constants are the tire sz (33") and ZF (5. something thru .76 I believe). I don't think I need to swap out the 411 in the rear to have good grunt in the haulin and still MPHs on the road. Just can't work the numbers for confidence and playin w/options. Can U walk me thru it again...

Mr Math Challenged

 

24" tire / 33" tire = .72 "tire factor"

granny gear (towing) 5.72 x 4.11 axle x .72 tire-factor = 17:1 towing 1st gear

2nd gear (DD) 2.94 x 4.11 axle x .72 tire-factor = 8.7:1 DD 1st gear

OD .76 x 4.11 axle x .72 tire-factor = 2.24 highway cruise

2.24 OD is a great highway ratio. 1600-1700RPM @ 60. You'll have no problem going way fast at low revs.

8.7 DD 1st is borderline. Your 3spd column/floor shift tranny (if you're talking about the truck in your sig) is 3.01 1st, which is very close to the ZF 2.94 2nd/DD 1st. If you're OK with 1st gear on your existing tranny, then you'll be OK with the ZF. Granny-low transmissions almost always get driven without 1st gear- 5speeds become 4, 4speeds become 3. The ZF would be the same as your exising 3-speed, with an overdrive, and a boat-pulling gear.

17:1 towing/granny is just fine for towing. That's what granny-low is in my truck, and it'll move anything (with the 300).

What engine?

NV3550 jeep tranny would work well in your application with your 4.11 axle (170/6 or 300/6). The 4.01 1st would be 4.01x4.11x.72 = 11.8:1 1st, which is good. That'll let you move your boat, and be easy to drive at the same time. A 170 will never have much oomph in OD, so be prepared to downshift to pass, and with any truck, never tow/haul in OD.

 

Again BB88 comes thru! U listening CoolGuy?
Lemmie peruse THESE factors!
Thanks,
cf

 

Yep I'm listining! Very helpful info thank you!

 

BigBlu-
Looks like you did the figuring for the ZF? I don't see all 5 gears, do I? Oh - U show what I currently have? Now, this is the 6cyl, called the heft, U sure U don't have figures for the more available/common ran and ren? which is the 2 60s/70s V8 tranis?
Same "tire factor for 24 thru 33 inch tires? I think stock for the Bronk was 27" (I got close to 31" now & wanna stop @ 33" for 8/8.5" ground clearance @ diffs [frnt&rear]).

<If you're OK with 1st gear on your existing tranny.>

Kinda spins the tires, gotta B careful.

<The ZF would be the same as your existing 3-speed, with an overdrive, and a boat-pulling gear. >

So it WOULD be like addin a 'top' and a 'bottom' to my current trani if I switched to the ZF? Exactly what I'm lookin for BrotherMan!

<be prepared to downshift to pass, and with any truck, never tow/haul in OD.>

6cyl R OK for a lill' luggin and do it regularly. Down shifts are part of the results. And yes all should know the dangers of no engine breaking.

(There's quite a few who put the NV3550 in these rigs, & some the ZF but on V8s)

<What engine? >

Also in sig. But I'd like to transplant an 80/81 250. I think it had a big alum. plenum on top,. don't know if it will fit under the hood but must have been a rudimentary/early FI of some sort. (A dream w/my income, but why not the diesel if dreamin? Some have this great 300 but it's as long as a train car! Some move the fire wall, others go forward [not sure how]). The 250 bolts right up to the ZF. There is the hydrol vs mechanical clutch change, however. I'd like to keep the (axles, transfer and) frnt/rear gears, now I hear from U, I suppose...

Am enjoyin this 'paper test' on possibilities. "Time to head in", sure to be a few min tossin a & turnin about this B 4 sleep comes. Should I thank or curse you??? ;-}
Thank you, of course,
cf

 

Hey I lied to you guys! I found my gear tag that was on the rear end. I knew I kept it when I changed the rear end gasket. Put it in my glove box! But the ID tag says 3L50 9 6C24. If I read that right it says 9" limited slip with 3.50 gears?? Not sure what the 6C24 means. So not the 3.73's I was thinking.