M5OD why did they choose the ratios they did for each gear?

[85_Ranger4x4]

I wonder how many people bitching about the tall 1st gear have ever actually driven a transmission with a respectably deep 1st gear. All that spinning mass doesn't do great things for shifting. The M5OD is actually really well spec'd out for what it is and what it got installed in. I've grossed 12k combined with my Ranger and other than wishing literally every gear was lower I can't find fault with the splits.

Low range in the transfer case covers for the transmission just fine since you can upshift at a ~5mph roll pretty well. The sliding dog in every transfer case I've ever had apart is beveled to facilitate this. That said, even ignoring the lack of synchro, this is a really shitty upshift on account of the huge gear split and reduction in RPM. The only reason it actually "works" when loaded is because the following gear (1st, high range) is sufficiently deep. This huge 1st/2nd drop is exactly what driving The 1.68 split of the normal 1st/2nd is actually pretty good because you can maintain RPM and acceleration.

What the M5OD could use, other than a deeper reverse, is a 6th gear below first.... Which is exactly what they did on the new Broncos.

Yeah, a creeper gear would be nice. Like dad's old T18.

Low range is nice, really puts first/reverse where I wish they were to start with and I am glad to have the ability to easily pop into 2lo on a whim. It's sitting parked in the barn in 2lo actually. To be fair my low range is only 2:1, most are like 2.75ish to one, many offroad tcases are more like 4:1.

I have mulled a doubler or even a ZF5 and maybe a regear to fix low range for offroad and od. As it is i cant fix one with regearing without making the other worse.

Broncos also have super deep axle gearing as well. My wife's on 32's has 4.46 gears, here I am on 31's with 3.73's...

 

[Eddo Rogue]

Changing rear diff will not bring the gears closer together - almost nothing you can do to do that, it will change your shift points (so instead of shifting at 20/30/40 you will do 25/35/45 or similar). If you are considering a diff swap, probably the best thing you could do besides staring at the chart is plug in all the relevant into this https://www.blocklayer.com/rpm-gear and then seeing where your shift points are... I haven't seen enough of a consistency in my traffic jams to get obsessed with moving shift point from 25 to 20 or 30, but speedlimits around here are very set and that is what I match to (65 state roads, 75 interstate)

I maybe said it the wrong way, I meant like rpms between shifts are lower...or like each gear is less "long" right?

 

[Eddo Rogue]

Unloaded and up to say 12k pounds total weight everything is perfectly fine, cruising at say 62mph is right around 2000rpm in 5th which is perfect for the engine, even 200rpm faster and the fuel starts flowing faster and the mileage goes down no matter what gear... If I got some stage one injectors, a tuner and an intercooler to gain 75hp I'm pretty sure I could just hold 4th on the long hills around here which would be perfect, it's on the list which I need to do this year.

By "screaming" what is your cruising speed and rpm now as well as gear ratio? If you can't hold first in parking lots I'm assuming 3.55 or 3.73. I'm pretty sure you might be overthinking what is bad rpm to hold for long periods, on my 2.3L the fuel mileage goes down when I hold over 3000rpm, in my V8 Explorers it seems to be 2k, the 4L is likely somewhere inbetween...

in my '90 with 5.13 gears and 35" tires it works pretty good for me with the lack of bottom end, with a 4L I don't think that would be as necessary and would probably want 4.56's or it wouldn't be highway friendly as I'm sure 3k at 60 isn't ideal but the 2.3L doesn't care...

Its has 3.73 stock 8.8" ...by screaming I mean if I had a 6th I would have shifted into it already lol

 

[Shran]

I wonder how many people bitching about the tall 1st gear have ever actually driven a transmission with a respectably deep 1st gear. All that spinning mass doesn't do great things for shifting. The M5OD is actually really well spec'd out for what it is and what it got installed in. I've grossed 12k combined with my Ranger and other than wishing literally every gear was lower I can't find fault with the splits.

Low range in the transfer case covers for the transmission just fine since you can upshift at a ~5mph roll pretty well. The sliding dog in every transfer case I've ever had apart is beveled to facilitate this. That said, even ignoring the lack of synchro, this is a really shitty upshift on account of the huge gear split and reduction in RPM. The only reason it actually "works" when loaded is because the following gear (1st, high range) is sufficiently deep. This huge 1st/2nd drop is exactly what driving The 1.68 split of the normal 1st/2nd is actually pretty good because you can maintain RPM and acceleration.

What the M5OD could use, other than a deeper reverse, is a 6th gear below first.... Which is exactly what they did on the new Broncos.

My old tow rig was an '85 F250 with a T19 and a 460... I have a T18 in my F150, a NP435 in my '86 Ranger, and have driven countless other old 4 and 5 speed trucks. Towing is an entirely separate discussion- that, and offroad stuff, is about the only time the low first gear is useful. I think just everyday use is the topic at hand, and IMO a SLIGHTLY lower 1st/2nd/3rd gear would have been nice. This is the gearing for our M5OD's:

Gear --- 2.3, 2.9, 3.0 ---- 4.0
1st 3.72 3.40
2nd 2.20 2.05
3rd 1.50 1.31
4th 1.00 1.00
5th(OD) 0.79 0.79
Reverse 3.40 3.40

Personally I think something like 4.00, 2.50, 1.60 would have been a good split. Especially for a 2wd truck powered by a 2.3 that may have had a 3.08 axle ratio. Some of the T19's in the big trucks had close ratio transmissions that had a 4:1 ratio first gear, those were very usable. I believe mine was one of the rare wide ratio ones, but there were a couple years that had a low first gear but only behind a 460.

Side note and somewhat to your point: have you driven anything that was way off the other way? That will really make you appreciate the M5OD for what it is I think... Take the SROD in the late 70's/early 80's F100's for example... I had one of those behind a 300 inline six, those have a 3.07 first gear. The lowest available was 3.25 for my 1980... I am fairly sure it was higher than that, probably 3.00. I remember not needing to shift out of 1st until I hit something like 30mph and had to ride the clutch forever or it would jerk around and stall out. It was totally useless for a lot of truck stuff but it was also kind of fun to drive once you figured out the clutch.

 

[Brain75]

I'll throw out something else.... and then agree with Shran.
So back in the hunt for a transmission for my 1948, I found out lots of stuff about how the industry changed - switched from expensive large machined splines to cheap small rolled splines, longer shafts since the smaller splines are weaker and so on and so on.
The big take was when the oil embargo and crunch hit everything pendulum swung to fuel efficient. Then throughout the 80's and into the 90's it was all about power to deal with the emissions strangulation.
Whether it was true or not, Ford/Chevy/Dodge kept chasing "power" under the belief that was what consumers wanted. A closer ratio transmission works better on a more powerful plant and gives the illusion/feel of more acceleration (at the expense of more often / closer shifting).
Since Shran's numbers became a headache to read after the formatting the forum software did I will post a snippet of my old research, reposting his numbers beside the T-5 options - you can see the less powerful 4 cyl in both Ford and Chevy used wider trans and the most powerful the closer transmissions. Personally I wish they would stick with the wider ratio no matter the power, I hate "useless" gears when 2nd and 4th are so close together why bother to use 3rd.

As far as my agreeing with Shran - have you ever driven some of the worse trans... I put the T-5 "medium" (from a 1990 V6 S-10) into my 1948 and it made it driveable, the old T8 was horrible. The ole 1981 F-150 with the NP435 was pretty miserable, basically all the bull nose 80's F-series I have driven were not fun to drive... I can't say I drove any cars that were stick other than an Opel (no idea what transmission it had) and some other rare things so not too much experience with too close, but ridden in a few mustangs that the guys only used odd numbered gears.

A snippet of my research from the winter of 2011/12 - just to give you a feel for some of the other transmissions discussed.

 

[arse_sidewards]

Rolled splined are stronger than cut for equivalent size for all the same reasons forged is better than milled from billet.

 

[Shran]

basically all the bull nose 80's F-series I have driven were not fun to drive...

You should take my F150 for a rip.

There were two types of bull nose trucks: those where you hit the gas, and waited; and those that let you know exactly what you did.

The EFI 302's that were in 85 & 86 F150's were pretty potent for the time period. I have a T18 in mine and while that is certainly something that shifts like a school bus, you have all 180 horses right there. 2nd & 3rd gear are so much fun, I especially like getting onto the interstate with a loaded trailer in 3rd gear and just letting it eat at WOT... true dual exhaust and glass packs is just so good.

First few times I drove it I was just totally shocked that it took no effort to speed in that truck. This was my land speed record - I have no idea what "M" equals but it's pretty frickin fast in a 40 year old truck.

 

[Curious Hound]

My 88 F150 4x4 with EFI 5.0l and manual 5 speed was very nice to drive. Wish I had that truck back.

 

[Eddo Rogue]

I really have no complaints about my M5OD. A lower first would be nice offroad. But for normal driving, its’s fine. I rarely use 5th anymore. But thats due to aerodynamics. 6” lift, altered body shape, big heavy tires, etc. and it has grown to over 5,000 lbs. My truck isnt like anyone elses. That’s why i haven’t really chimed in here until now. But my little transmission works hard for me.

Thats the perfect situation for a simple axle gear swap. lower ratio would give you a lower first and you can use 5th. If I had an extra gear I never use, that would solve my problem, I would swap the 3.73 for 4.10 or even 4.46 and be a happy camper.

Now if you not only used 5th, but it was still too low. and 1st still to tall....then you would have my conundrum.

 

[Eddo Rogue]

My buddy had a single cab F150 w the 302 and 5spd...I think it was T5, '92 or '94 IIRC. This was 25 years ago. He sold it and then got a '92 ranger w autofab 16" travel kit. He was one of those guys that always had something super cool, but never held on to it long, was always buying and selling.

I also drove his brothers suburban w a muncie 4 spd granny 1st. It was a military surplus or something. had metric gauges lol. He put a Mark V 454 in it...ah the good old days of pushrod big blocks.

I had a 2.9L ranger for a bit...dont know what 5 spd was in it. it was an absolute dog, couldnt get out of its own way. It was lifted on 33" but had been regeared...still an absolute pig.


late 80's early 90's square body fords were/are my favorite.