Second Gear

[rat4spd]

First, the physics of accelerating a truck from zero to 2 MPH in 3 seconds is no different than going from 2MPH to 4MPH in 3 seconds, or 100MPH to 102MPH in 3 seconds. Speed is relative.... it is all F = MA Notice that F = MA doesn't mention speed.


Acceleration=Change in velocity (ergo...speed) divided by time.
This formula neglects things such as rolling resistance, wind resistance, difference in frictional losses, and the difference in power applied off idle as opposed to throttling through the gear.

However, I digress....and will still use second gear.

 

[Billy Bobbed]

Ive seen alot of people that use these trucks as mud boggers,stump pullers,creek crossers,hill climbers,snowmobles,and try to pull anything out that they can.That could be a couple reasons why they go out.Then a couple weeks down the road the trans goes out.Then say they been driving it lke an angel,that cant be it.I seen alot of people on youtube just trashing these trucks.I would say they have it in 2nd gear in the low side of the transfer case.Who knows.

 

[stumps]

First, the physics of accelerating a truck from zero to 2 MPH in 3 seconds is no different than going from 2MPH to 4MPH in 3 seconds, or 100MPH to 102MPH in 3 seconds. Speed is relative.... it is all F = MA Notice that F = MA doesn't mention speed.


Acceleration=Change in velocity (ergo...speed) divided by time.

And your point is?

Show me how the force required to accelerate at 1g changes when you go from 0 to 2MPH, 2 to 4MPH, and 100 to 102MPH.

This formula neglects things such as rolling resistance, wind resistance, difference in frictional losses, and the difference in power applied off idle as opposed to throttling through the gear.

Imagine that! I simplified things .

Since we are talking about first and second gear, and we are arguing about whether it is ok to start in second, vs first, I should think that wind resistance, rolling resistance, and frictional losses would be pretty darn close to the same in either case.

However, I digress....and will still use second gear.

Since I doubt I will be the one fixing your transmission, it probably won't affect me whichever way you choose.

The nature of free advice is you can follow it or not as you choose.

I will leave you with this one last data point: If you use the clutch in exactly the same way starting off in second as you do in first, your clutch, and transmission input shaft, will be seeing 1.78 times more torque starting out in 2nd gear than they will starting out in first. If the clutch chatters in 2nd, but not in first, it will be considerably more than 1.78 times.

-Chuck

 

[tm america]

my guess would be the trans that have broken second were not broke from starting out in second as the engine torque is very limited at near idle. but instead they get broke from downshifting into second at to high of a speed as then the second gear see the full load of the truck and cargo.if you are downshifting to early on most vehicles it will just blow one side for the clutch off. but since these trucks have a ceramic clutch and the trans has a weak link in second.i would bet they are failing for that reason not starting off in second. you have to look at the way the keyways and keys have failed if they were ripped off one way. it would mean on accell the other would mean deccell. i rebuild transmissions for a living and know that you cant just guess at why they failed. you have to do a little detective work and look at the way they failed so you can do the proper things to fix the issue. i start in second most of the time my motor is turned up more that most. i have been doing this for at least 6yrs loaded or not no failure of second .i do not use my trans for engine braking in second . maybe this is why mine hasnt failed?

 

[Billy Bobbed]

I cant get mine in 2nd gear when I down shift,im almost at a stop before I can get it in 2nd gear.

 

[rat4spd]

And your point is?

You said speed was not in the equation. That's my only point.

Show me how the force required to accelerate at 1g changes when you go from 0 to 2MPH, 2 to 4MPH, and 100 to 102MPH

Can't do it using a simplified equation. Surely you understand the effect of wind resistance are substantail at 100 MPH as compared to 2 MPH.

Since we are talking about first and second gear, and we are arguing about whether it is ok to start in second, vs first, I should think that wind resistance, rolling resistance, and frictional losses would be pretty darn close to the same in either case. .

Agreed. However you extended the example to 100 MPH.

Since I doubt I will be the one fixing your transmission, it probably won't affect me whichever way you choose.

It indeed will not, as I will probably part the truck out anyway. This truck isn't an LS6 Chevelle or an L88 Corvette, it's just a big military truck.

The nature of free advice is you can follow it or not as you choose..

Fair enough

I will leave you with this one last data point: If you use the clutch in exactly the same way starting off in second as you do in first, your clutch, and transmission input shaft, will be seeing 1.78 times more torque starting out in 2nd gear than they will starting out in first. If the clutch chatters in 2nd, but not in first, it will be considerably more than 1.78 times.

My contention has nothing to do with comparing first and second gear.

 

[Billy Bobbed]

When I drove today, I took of in 2nd gear all day.I cant go back to 1st gear.I drove my deuce reg. and bobbed with 46 inch tires.I cant take off in 1st gear etheir way.In my opinion there is not enough momentum to go from 1st to 2nd.Did they ever put lower gears in some deuces.It takes off so much better in 2nd.

 

[tm america]

first to second sucks. try going second trans low transfer case then pull trans fer case up to high then drive out the rest of the gears it gives you close to the same ratio as in first but that way it is syncronized

 

[wldrbob]

when we drove our old 4 speed grain truck with bull low you could not shift from first to second unless you were reved right to the max i think it did only 2 or 3 mph seemed prety slow anyways. empty we always started out in second and sometimes in the yard where it was hard ground loaded .. it could hold 150 plus bu of wheat 9000 lbs or so a bit overloaded for a one ton lol. the motor was not great but we never hurt the trans.

 

[stumps]

When I drove today, I took of in 2nd gear all day.I cant go back to 1st gear.I drove my deuce reg. and bobbed with 46 inch tires.I cant take off in 1st gear etheir way.In my opinion there is not enough momentum to go from 1st to 2nd.Did they ever put lower gears in some deuces.It takes off so much better in 2nd.

I must be missing something. Are you saying your truck has stopped before you can get into 2nd gear? If so, something is wrong with your truck.

-Chuck

 

[Billy Bobbed]

I must be missing something. Are you saying your truck has stopped before you can get into 2nd gear? If so, something is wrong with your truck.

-Chuck

No im going about 10 mph.

 

[Billy Bobbed]

It might be less than that,probably more like 5mph

 

[stumps]

It might be less than that,probably more like 5mph

That is about all you should expect out of 1st gear. I typically let the truck get to 8 or 9MPH with my stock deuce... 9MPH is the red line.

The gearing is such that whatever RPM you get to in first gear, the RPM will need to be a little more than 1/2 that much in second gear. For instance if you get to 2400 rpm in first, second would like to be about 1300 RPM... (That holds for all gears except 5th, which wants more, half again as much more (2000RPM)).

Bring the engine up to 1300-1400 RPM as you let the clutch out in second gear. Let the clutch slip a bit to get you over the hump, if necessary. That small amount of slippage is far better for your clutch than the large amount required to get it going from a dead stop in second gear.

-Chuck

 

[jdmcgowen]

Well I'm not sure about the whole starting out in second, but my truck doesn't like to shift out of second when I'm down shifting to a stop. I'm guessing my syncro's are probably messed up, but I'm not sure what kind of a fix that is, so I haven't tried to tackle it. If it's an easy fix, I may try it. I thought at first my clutch wasn't disengaging, but my clutch doesn't engage until the pedal is about 1 1/2 to 2 inches from fully out position. Any ideas here?

 

[stumps]

Well I'm not sure about the whole starting out in second, but my truck doesn't like to shift out of second when I'm down shifting to a stop. I'm guessing my syncro's are probably messed up, but I'm not sure what kind of a fix that is, so I haven't tried to tackle it. If it's an easy fix, I may try it. I thought at first my clutch wasn't disengaging, but my clutch doesn't engage until the pedal is about 1 1/2 to 2 inches from fully out position. Any ideas here?

There is more to the clutch than just the clutch disk. If your pilot bearing (the bearing in the end of the crankshaft that centers the transmission shaft) is gummy, the transmission guts will continue to turn at engine speed when you press the clutch pedal. That could be putting enough force on the gears to make it hard to slip out of 2nd.

Try depressing the clutch, and putting pressure on the shifter towards neutral, and then speed the engine up a little, and then letting it slow down. It should slip out of 2nd when the engine passes from driving the transmission to being driven by the transmission.

-Chuck

 

[jdmcgowen]

I'll try that Stumps, thanks for the input. Been driving this thing for a year now and I'm still learning it's quirks.

 

[m-35tom]

chuck, you don't have to 'slip' the clutch to start out in 2nd with an empty truck. if you do, you have an engine power problem.

it is much more likely for the disk to not slide easily on the input shaft and thus still have a small drag on the flywheel. you can check this by drpressing the clutch at a stop and trying to engage 1st or rev. if the disk is dragging it will want to grind slightly. if severe, more than slightly.

tom

 

[stumps]

chuck, you don't have to 'slip' the clutch to start out in 2nd with an empty truck. if you do, you have an engine power problem.

You keep saying that, but either you don't know what "slipping the clutch" means, or you are intentionally trying to talk people into breaking their trucks.

In first gear, 2600RPM = 9MPH therefore,

800RPM x 9MPH/2600RPM = 2.8 MPH

In second gear, 2600RPM = 16MPH therefore,

800RPM x 16MPH/2600RPM = 4.9 MPH

If you don't slip the clutch, you are asking your truck to instantly accelerate to 2.8 MPH if you are in first gear, and 4.9 MPH if you are in second. That is just plain wrong!

So which is it?

-Chuck

[This post is much meaner than I meant for it to be - Sorry! -Chuck]

 

[mudguppy]

chuck, i think there's a gap between what you are saying and what Tom is saying.

when you spoke of slipping the clutch, you also mentioned applying engine throttle.

when Tom speaks of not slipping the clutch (as have i), he is just talking about easing the clutch out with the engine at idle. yes, obviously the clutch still is slipping some, but not near as must as, say, driving a gasser car and having to apply gas and clutch simultaneously. so, if you have to apply throttle during let-out, then your idle is too low, gear selection is too high, or the truck is laden.

i drive how Tom refers - let the clutch out to get you moving. once the clutch/engine rpms are matching and fully engaged, then apply throttle. this manor only exposes the transmission to 'let-out torque' of the engine from a stand-still.

driving this way (in whatever gear you want to start in) virtually eliminates torque spikes through the trans. this is also the method used by OTR drivers..... well, those that still shift, anymore.

 

[DUG]

If I kill second gear in the process, it deserved it.

Please do not mind the reply, If your second goes , and it may never , It will only be driver error, not the trucks fault...Now i am just stating a fact because so many guys blame there trucks when things go wrong, Like the tires got me stuck is the one that makes me laugh the loudest...just saying i am sure u said it in jest, But it will only go if it is over driven and/or over loaded,none the trucks fault ...Randy

No I'm sure he said it with 100% seriousness. Rat always blames something for his troubles - ask him about the Mt Dew bottle that broke his tooth or the door that smashed his finger. So if his 2nd gear goes, it WILL be the trucks fault and that gear DESERVED to die and the only one getting screwed is Rat, who will have to use his checkbook, massive tool collection and new garage to set things right again.