7MT Tech

[KH_59]

Getrag-Ford says the 7MT (officially, the 7MTI550) is baseline rated at 550 Newton-meters (406lb-ft), but is scalable to as much as 800Nm (590 lb-ft) in passenger car applications.


They reference the Pickup Truck and Light Commercial Vehicle segments in their tech sheet, so it would seem likely this transmission design will be coupled with various engines going forward (in other vehicles, at least).

https://www.getrag-ford.com/files/theme/downloads/6MTI550_Manual_Inline_Transmission.pdf

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[Hoofnmouth]

Kinda cool looking! Better than that red slime blooded mushy shift whenever it wants to heavy chunk of s#@t.
Come on august!

 

[BLTN]

Marginal capacity for a tuned 2.7, though...even a hot 2.3 tune may push it.
Work on it, Getrag - We're counting on YOU!

 

[Toccoa]

Kinda cool looking! Better than that red slime blooded mushy shift whenever it wants to heavy chunk of s#@t.
Come on august!

I feel like you’re holding back. ?

 

[Blksn955.o]

Stupid integrated bell housing. Cant wait to get my hands on mine...

 

[Laminar]

Getrag-Ford says the 7MT (officially, the 7MTI550) is baseline rated at 550 Newton-meters (406lb-ft), but is scalable to 650N-m (479lb-ft).

Read it again. The 650 value is for Light Commercial Vehicles (delivery vans), for Passenger Cars it goes up to 800Nm (590 lb-ft).

Marginal capacity for a tuned 2.7, though...even a hot 2.3 tune may push it.
Work on it, Getrag - We're counting on YOU!

See above.

 

[attworth]

I wonder which spec Ford is putting in the Bronco. 406 ft lbs doesn’t leave much room for tuning. Cobb gets 378 out of the mustang, and accounting for 15% drivetrain loss that’s 445.

 

[KH_59]

Read it again. The 650 value is for Light Commercial Vehicles (delivery vans), for Passenger Cars it goes up to 800Nm (590 lb-ft).

Good catch. Original post updated. Thanks!

 

[Laminar]

I wonder which spec Ford is putting in the Bronco. 406 ft lbs doesn’t leave much room for tuning. Cobb gets 378 out of the mustang, and accounting for 15% drivetrain loss that’s 445.

It's really hard to put a real number to what a transmission can take. The biggest risk to a transmission isn't usually peak power or torque, but a combination of weight, traction, and shock loading. Given the same input power, a large truck with big wheels and tires would stress the transmission differently than a small car on skinny all-seasons.

Rock crawling or towing or drag racing or road racing all load a transmission differently and 400ft-lb hitting the trans during a drag launch on a prepped surface is different from building up 400ft-lb down a long straight on a road course, which is different from bouncing up a rocky trail.

The problem we have is this: Everything Ford says is marketing. Every statement made, every engineering detail divulged, every number or capacity released to the public has been very carefully vetted and designed specifically to serve a marketing purpose. We will not know what take rates they projected for the manual with either engine. We will not know the designed strength of each gear in the transmission or the safety factor built in to their rating. We won't know what the actual fuse in the drivetrain is, even though Ford knows - is it the half-shafts, or the driveshaft, or the transfer case, or the transmission?

The only theory I've heard that I've liked so far is that the 2.7 with the crawler gear would put a monumental amount of torque on the downstream components.

400lb-ft x the 67.8 crawl ratio of a 10A/sas is 27,520 lb-ft after all of the torque multiplication.

310lb-ft x the 94.9 crawl ratio of a 7M/sas is 29,357 lb-ft which is definitely in the same ballpark.

400lb-ft with the manual would be 37,960lb-ft, a significant increase for the transfer case, driveshaft, diffs, and halfshafts to handle, especially when coupled with the heavy Sasquatch 35s.

 

[Hoofnmouth]

It's really hard to put a real number to what a transmission can take. The biggest risk to a transmission isn't usually peak power or torque, but a combination of weight, traction, and shock loading. Given the same input power, a large truck with big wheels and tires would stress the transmission differently than a small car on skinny all-seasons.

Rock crawling or towing or drag racing or road racing all load a transmission differently and 400ft-lb hitting the trans during a drag launch on a prepped surface is different from building up 400ft-lb down a long straight on a road course, which is different from bouncing up a rocky trail.

The problem we have is this: Everything Ford says is marketing. Every statement made, every engineering detail divulged, every number or capacity released to the public has been very carefully vetted and designed specifically to serve a marketing purpose. We will not know what take rates they projected for the manual with either engine. We will not know the designed strength of each gear in the transmission or the safety factor built in to their rating. We won't know what the actual fuse in the drivetrain is, even though Ford knows - is it the half-shafts, or the driveshaft, or the transfer case, or the transmission?

The only theory I've heard that I've liked so far is that the 2.7 with the crawler gear would put a monumental amount of torque on the downstream components.

400lb-ft x the 67.8 crawl ratio of a 10A/sas is 27,520 lb-ft after all of the torque multiplication.

310lb-ft x the 94.9 crawl ratio of a 7M/sas is 29,357 lb-ft which is definitely in the same ballpark.

400lb-ft with the manual would be 37,960lb-ft, a significant increase for the transfer case, driveshaft, diffs, and halfshafts to handle, especially when coupled with the heavy Sasquatch 35s.

The fuse is gonna be those ifs shafts ,we will see though?

 

[attworth]

It's really hard to put a real number to what a transmission can take. The biggest risk to a transmission isn't usually peak power or torque, but a combination of weight, traction, and shock loading. Given the same input power, a large truck with big wheels and tires would stress the transmission differently than a small car on skinny all-seasons.

Rock crawling or towing or drag racing or road racing all load a transmission differently and 400ft-lb hitting the trans during a drag launch on a prepped surface is different from building up 400ft-lb down a long straight on a road course, which is different from bouncing up a rocky trail.

The problem we have is this: Everything Ford says is marketing. Every statement made, every engineering detail divulged, every number or capacity released to the public has been very carefully vetted and designed specifically to serve a marketing purpose. We will not know what take rates they projected for the manual with either engine. We will not know the designed strength of each gear in the transmission or the safety factor built in to their rating. We won't know what the actual fuse in the drivetrain is, even though Ford knows - is it the half-shafts, or the driveshaft, or the transfer case, or the transmission?

The only theory I've heard that I've liked so far is that the 2.7 with the crawler gear would put a monumental amount of torque on the downstream components.

400lb-ft x the 67.8 crawl ratio of a 10A/sas is 27,520 lb-ft after all of the torque multiplication.

310lb-ft x the 94.9 crawl ratio of a 7M/sas is 29,357 lb-ft which is definitely in the same ballpark.

400lb-ft with the manual would be 37,960lb-ft, a significant increase for the transfer case, driveshaft, diffs, and halfshafts to handle, especially when coupled with the heavy Sasquatch 35s.

I think in the Engineering Explained video of the 7MT, he talks about how Ford likely limits torque output in C gear because of that huge torque number.

I drive like a granny, and I’m super conservative off road, so hopefully I won’t break anything too quickly. Haha.

 

[tlowell01]

The problem we have is this: Everything Ford says is marketing. Every statement made, every engineering detail divulged, every number or capacity released to the public has been very carefully vetted and designed specifically to serve a marketing purpose. We will not know what take rates they projected for the manual with either engine. We will not know the designed strength of each gear in the transmission or the safety factor built in to their rating. We won't know what the actual fuse in the drivetrain is, even though Ford knows - is it the half-shafts, or the driveshaft, or the transfer case, or the transmission?

The only theory I've heard that I've liked so far is that the 2.7 with the crawler gear would put a monumental amount of torque on the downstream components.

I guarantee every comment Ford has released has been carefully vetted by Design, engineering, marketing, and legal. If John Q. Public and their lawyers didn’t sue companies for everything under the sun, they might be a bit more open about things. As it is, if Ford released the theoretical maximums of the transmission (in addition to their “official” ratings), and the transmission didn’t hold up to the maximum ratings, all of a sudden Ford is in an actionable legal situation.

As far as the 2.7 goes, the take rate of the MT isn’t going to be high enough to justify engineering and certifying another power train option. It’s as simple as that.

 

[Laminar]

I guarantee every comment Ford has released has been carefully vetted by Design, engineering, marketing, and legal. If John Q. Public and their lawyers didn’t sue companies for everything under the sun,

It's more for competitive purposes. No way am I revealing to my competitors our internal processes, standards, or calculations.

As far as the 2.7 goes, the take rate of the MT isn’t going to be high enough to justify engineering and certifying another power train option. It’s as simple as that.

 

[tlowell01]

I’m getting a MT too, but I have no illusions how many they are going to sell with MT. I doubt the MT sticks around more than a couple MY’s.

 

[Rocketeer Rick]

The only theory I've heard that I've liked so far is that the 2.7 with the crawler gear would put a monumental amount of torque on the downstream components.

400lb-ft x the 67.8 crawl ratio of a 10A/sas is 27,520 lb-ft after all of the torque multiplication.

310lb-ft x the 94.9 crawl ratio of a 7M/sas is 29,357 lb-ft which is definitely in the same ballpark.

400lb-ft with the manual would be 37,960lb-ft, a significant increase for the transfer case, driveshaft, diffs, and halfshafts to handle, especially when coupled with the heavy Sasquatch 35s.

This is a good start, but does not account for two important things when determining how much peak torque the driveline will see.

1) Impact factor. This is an additional multiplication factor that accounts for the inertial wind up and release that occurs when you perform a drag-style launch. It is hard to predict accurately, but for a manual transmission with a plate clutch, this can be 2.5-3:1. For an automatic, the torque convertor dampens the impact some, so here the factor might only be 1.5 or 2:1. This is, as I said, an extra factor that you multiply with all the gear ratios that you also multiplied the engine torque by. So, from that point of view, your peak torque numbers are actually low.

Also, tied to this, it is most likely that the torque multiplications would disregard low range in the t-case, and would probably use 2nd gear - since 1st is a granny gear and does not act as the 1st gear in normal operation. With the low range and crawl gear, the assumption is likely to be that the duty cycle of these gears is only at low speeds and in crawling scenarios. No one in their right mind will wind up the engine and dump the clutch while in crawl/low range - that's a fast way to break the transmission output shaft, or other things.

2) Tire traction. Everything I just said is true and needs to be considered, but the actual limiting factor of max torque is tire traction. You can only generate the torque that you have enough traction to support; this comes from Newton's 3rd law. So, the tires are usually the fuse in the system - you will max out the tires (and spin them) typically way before you see 27K lb-ft on the axles. For a point of reference, even the GT500 - supercharger and everything - only puts down about 15K lb-ft at the axle before the (stock) tires break loose and spin.

A 4WD/AWD car can put down more, but it isn't double, due to dynamic weight shift. And, of course, the engineering team has to look at it in a 2WD mode as most severe, since that's the case when the tires will see their highest friction coefficient (grip levels) on dry asphalt.

The bottom line here is this - if the Sasquatch tires are Bronco's worst case scenario in terms of inertia and grip, as far as the driveline is concerned, then that limit is the same regardless of which engine is in place. If the 2.3L Sasquatch can max out and spin the tires, then the V6 won't add more peak torque to the driveline.

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