down shifting

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slowdown

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This is my first mopar 4 speed so I am not sure if what is going on is normal. When driving say 45 mph in 4th gear should I be able to just down shift to third after letting off the gas an slowing down a little. Seems like it won't down shift till the car slows down enough to go into a lower gear. Is this normal? I was watching a youtube video of a small block mopar doing the 1/4 and at the end of the race he was dropping gears and slowing the car down, I could hear it revving while he was down shifting. I can get it to down shift but only after slowing down and revving the gas pedal a little and it will down shift. I had a rock crusher when I was a kid and I don't remember having to do this when down shifting. The car shifts fine other then this question.
 
Did you rebuild it? Does it only do this going into 3rd or does it do it going from 4th to 2nd.
 
It mostly depends on rpm, gear ratio and to degree tire size.
Basicly, if you have to force it, it shouldn't be done.

It could be some worn out parts within that doesn't effect normal driving.

My friend forced his during a race, he made it go into 3rd and quickly popped the engine.
 
X2^ i can down shift into third at 40 or 45 . Check and make sure your shift linkage is adjusted properly
 
71DodgeDemon340 said:
Lmao ^ i sure hope he is :blob:
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it takes time but you can shift without it but the reason i ask is his first sentence...

"This is my first mopar 4 speed so I am not sure if what is going on is normal. When driving say 45 mph in 4th gear should I be able to just down shift to third after letting off the gas an slowing down a little"

slows down and takes the load of to shift, but if you dont get the rpm's right its not going to into the other gear...
 
If the clutch is releasing clean, here's what you should be able to do............

In the past, I've ACCIDENTLY shifted from 4th to 1st at highway speed. Now I did get it into gear, and realized before I completely engaged the clutch, so no, I didn't over-rev the engine

So to be crystal clear here's what I'm referring to

Let's say you are running 70-75 with a "normal" geared car, 3.5 or so rear axle. You put in the clutch, you leave the throttle alone, you should be able to stuff it right into 1st

HERE IS WHY you don't want to do that...........with the car going that speed, and even with the clutch "in" (to the floor) that clutch disc is gonna be spinning at a VERY high RPM

Let's "just say" in my old RR, 70 mph was close to 3K RPM in 4th. With a 4 speed, say, 2.47 1st gear, this means the disc will be spinning at 2.47 X 3000, or 7400 RPM

My point, though, is this...........

IF the clutch is releasing "clean"

and IF the gearbox and syncros is in good shape, it SHOULD go into gear. "It might" take a little more "push" on the shift lever to do so, but it should not grind
 
X2^ mine would grind a little bit going from fourth to third. Re adjusted the shift linkages and it went in just fine.
 
You probably have a diaphragm pressure plate with a standard 5 1/4 inch pin spread on the clutch pedal. You need to go to a 6 inch pin spread and the clutch will release properly. Or get a borg&Beck/3 finger pressure plate. Just a thought of what could be wrong. There is a thread on this find it.
 
Oldmanmopar said:
forth to third has nothing to do with shift linkage adjustment.
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The way my linkage was adjusted it wasnt going into third all the way and would only grind going from fourth to third never made a sound going from second to third. Anyways i adjusted the linkage to where i could tell third was going in all the way and it fixed the problem. I had to much throw going into fourth and not enough going back into third
 
The tran has been rebuilt and has new clutch p plate and throw out bearing. I am pushing in the clutch when shifting. I haven't tried double clutching it, but it does shift fine. I wanted to down shift and use the clutch to slow the car and it didn't want to do it unless I slowed down a little or I revved it a little while slowing and then it would go into a lower gear. I know they aren't like a modern 5 speed that down shifts at almost any speed, but I just was wondering if this was normal.
 
The lubricant you are using could be causing problem also, but downshifting from 4th to 3rd is a completely normal function and shouldn't resist unless there is a worn syncro or worn face on the gear for the syncro.

If all else works correctly then it is a syncro function or lubricant problem.
 
It seems to me that you need to learn to blip the throttle. Without blipping, your syncro-rings will give up sooner or later, leading to grinding, leading to clutch-tooth damage and an early rebuild. It may seem cool to slow the car with compression braking but until you learn how, the brake pads/shoes are way cheaper to replace. just saying.
 
AJ/FormS said:
It seems to me that you need to learn to blip the throttle. .
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"Blipping the throttle" does absolutely nothing to help save the syncro rings. Unless the clutch is dragging, and that in itself is hard on them.

You must DOUBLE CLUTCH and use (blip) the throttle for engine RPM to affect syncros.

But this thread is more about the OP being ABLE to go from 4th to 3rd at a reasonable speed and RPM, something he didn't seem to be able to do.


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When I used to get in a speed contest in my 340 cuda in high school. I would go straight from 4th to 2nd to get on it. We called it the "famed double down-shift". This was usually when going 35-40 mph as most races occurred on the fly. There was no blipping the throttle, went to second smooth as silk.
Rod
 
Not sure about American cars but you only really need the clutch for starting off, usually in first. As long as you are off the throttle, the trans should shift.

I would say you have a problem.
 
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