towing with a straight shift
CO River Rat
Joined: Feb 2004
Posts: 3,209
Likes: 0
From: Lake Havasu City AZ
Jared -
This is from Ford's new vehicle warranty:
"Note: Brake pads, brake shoes, brake discs, clutch and any other friction related components are not covered when replacement is due to wear and tear, but they are covered against manufacturing defects for the duration of the Ford Base Warranty"
Based on the above, Ford would NOT be replacing clutches under warranty for wear and tear.
Steve
This is from Ford's new vehicle warranty:
"Note: Brake pads, brake shoes, brake discs, clutch and any other friction related components are not covered when replacement is due to wear and tear, but they are covered against manufacturing defects for the duration of the Ford Base Warranty"
Based on the above, Ford would NOT be replacing clutches under warranty for wear and tear.
Steve
Hotshot
Joined: Oct 2002
Posts: 18,488
Likes: 22
From: The Big, Oregon
If a clutch dies at 10-12k, it gets replaced under warranty. If you burn up another one within the warranty period, it's usually declared abuse and is not covered.
I have dealt with this in a dealership situation before.
I have dealt with this in a dealership situation before.
Cargo Master
Joined: Jun 2008
Posts: 2,752
Likes: 5
From: Stillwater, OK
The manual trucks typically came with a 3.5 rear ratio, or higher and as a result if they had a high tow rating then Ford would be replacing clutches under warranty. The manuals tended to be the fuel economy trucks, plus the transmissions were a bit on the weak side. They just couldn't hold up to a full size truck towing a real trailer with a V8.
even in the 5-speeds, 1st was 5.72:1
1st gear on a torqshift is 3.11:1 a torque converter would have to have a 1.8x multiplier to match a manual... I can't find the low gear ratio for a 98 right now...
CO River Rat
Joined: Feb 2004
Posts: 3,209
Likes: 0
From: Lake Havasu City AZ
Actually, torque converters have a multiplier of around 2; here's one article with some good info: Torque Converters Explained
Steve
Steve
Cargo Master
Joined: Jun 2008
Posts: 2,752
Likes: 5
From: Stillwater, OK
The difference in speeds creates the vortex flow through the stator, and applies full torque multiplication (2:1). While this multiplication phase makes tremendous power, it also generates tremendous heat and drastically reduces efficiency: if the converter were to stay in this phase continually (as it would if your stall speed was too high) the transmission's life would be greatly shortened, and efficiency would suffer. To adjust for this, as the vehicle picks up speed and the drive train (turbine) speed catches up to that of the engine (impeller), the converter gradually reduces vortex flow, until the entire assembly is turning at nearly the same speed in the coupling phase. This increases efficiency and reduces heat.
The article is written referencing unloaded vehicles, not overloaded ones. When towing with an automatic, if your load is such that your torque converter can never lock up (or worse yet, you're towing without a lockup converter) you are essentially just burning fluid...
oh, and a 2x torque converter, running at 90% efficency would result in a gain of 1.8x
Hotshot
Joined: Oct 2002
Posts: 18,488
Likes: 22
From: The Big, Oregon
You're talking Super Duty, I was referencing the 5speed in the F150, the M5R2. First in the M5R2 is 3.75, which is great for my diesel project, but not for the OHC 4.6 and 5.4. Neither of these had very good off-idle torque at that time, so you'd have to slip the clutch.
Cargo Master
Joined: Jun 2008
Posts: 2,752
Likes: 5
From: Stillwater, OK
so you'd have to slip the clutch
When you slip a clutch, you've stored energy in the flywheel... with more HP stored, the faster you try to let it out, the more torque it puts though the transmission... it isn't quite as smooth, but does the exact same thing as a torque converter.
Post Fiend
Joined: Jun 2002
Posts: 13,873
Likes: 3
From: Atlanta GA
It comes down to clutch material surface, it's holding power, and when it is going to slip when exposed to so many foot pounds. Sometime this can be over come by gearing.
Example: My B2 with a 5 speed on a steep hill, will slip backwards down a steep hill when parked. When put into 4WD LO it will not. If I upgrade to a 4.0 clutch starter it has far more grabbing power simply because there is more surface area on the clutch disc.
Same thing with the brakes, a 7.5 will not hold a B2 on a very steep incline, a 8.8 will. Surface area vs. force applied.
Same holds true with a clutch and that is why diesels have huge dual mass clutches and can tow almost as much as an automatic diesel.
.
Example: My B2 with a 5 speed on a steep hill, will slip backwards down a steep hill when parked. When put into 4WD LO it will not. If I upgrade to a 4.0 clutch starter it has far more grabbing power simply because there is more surface area on the clutch disc.
Same thing with the brakes, a 7.5 will not hold a B2 on a very steep incline, a 8.8 will. Surface area vs. force applied.
Same holds true with a clutch and that is why diesels have huge dual mass clutches and can tow almost as much as an automatic diesel.
.
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Senior User
Joined: Apr 2008
Posts: 176
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From: Arizona
You're not storing energy in the flywheel when you slip the clutch. The clutch just connects the engine to the transmission/drivetrain. When you slip the clutch you are actually limiting the amount of energy being transferred to the wheels. The goal in slipping the clutch is to help match the speed of the engine to the speed of the vehicle (which includes gearing). If you don't match the speeds correctly you can either bog the engine, make the vehicle jump erratically since the engine speed and vehicle speed are trying to "match", or overcomes the friction limits of the tires - burn rubber. Slipping the clutch actually loses power, it's transferred to heat. Same as a torque converter.
And to contradict what I just said, there is a small amount of energy stored in the flywheel, but it is small relative to the output of the engine. (The engine does not spin for 5 minutes after you shut if off due to all this energy.)
Cargo Master
Joined: Jun 2008
Posts: 2,752
Likes: 5
From: Stillwater, OK
you're right, I meant "dump the clutch" ...It takes all of the energy stored in the flywheel & rotating assembly and instanly transfers it to the drivetrain... If the engine can't keep up after the quick boost, you stall...
slipping it just heats an unvented friction surface, but can still be used as a useful tool. Slip the clutch with the input side moving much faster than necessary to get the output side moving, and you can drop the speed of the input side to match and go.
yes, but the power output of the engine is a point output... alone it cannot do anything, because work is dependent on time. if time =0 work =0. The power produced by the engine is turned to energy by the rotating assembly, and eventually work by the moving vehcle.
once the vehicle is rolling, it acts as an energy accumulator (flywheel) itself, which is why the flywheel doesn't have to store that much energy...also why it is nearly impossible to stall while rolling.
slipping it just heats an unvented friction surface, but can still be used as a useful tool. Slip the clutch with the input side moving much faster than necessary to get the output side moving, and you can drop the speed of the input side to match and go.
there is a small amount of energy stored in the flywheel, but it is small relative to the output of the engine.
once the vehicle is rolling, it acts as an energy accumulator (flywheel) itself, which is why the flywheel doesn't have to store that much energy...also why it is nearly impossible to stall while rolling.
Elder User
Joined: Nov 2006
Posts: 973
Likes: 2
From: Texas
Slipping the clutch allows the engine to produce more power at a higher rpm while trying to get the truck moving while the trans spins at a lower rpm.
Most people that tow with a manual don't realize that you DO NOT slip the clutch. You must let the engine bog down and pull the load. Before i swapped to a ZF-5 i would lug the engine down to 500rpm or so when pulling loads up steep hills at super slow speed. A manual trans is much stronger then any pre-2000 auto trans. Newer auto trans' have become much stronger, but its still hard to match the strength of a manual. Its hard to bet a gear to gear transfer of power.
Ford just did want to deal with the warranty issues of the clutch.
And one thing i noticed is that the 92 truck tow ratings are much more consistent between manual and auto, they also dont have different rating for f150-f350, just differences for engine, trans, rear gear ratios.
Most people that tow with a manual don't realize that you DO NOT slip the clutch. You must let the engine bog down and pull the load. Before i swapped to a ZF-5 i would lug the engine down to 500rpm or so when pulling loads up steep hills at super slow speed. A manual trans is much stronger then any pre-2000 auto trans. Newer auto trans' have become much stronger, but its still hard to match the strength of a manual. Its hard to bet a gear to gear transfer of power.
Ford just did want to deal with the warranty issues of the clutch.
And one thing i noticed is that the 92 truck tow ratings are much more consistent between manual and auto, they also dont have different rating for f150-f350, just differences for engine, trans, rear gear ratios.
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JSowell23
1987 - 1996 F150 & Larger F-Series Trucks
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