slack in drivetrain?

[Drew99GT]

Does anyone elses car have severe "slack" in their drivetrains/drivelines? What I mean is, when I let off the gas in my car ( 5speed manual Toyota Corolla) I get some jerkiness and a general feeling of a lot of slack in the tranny etc. It mainly does it in 1st gear for sure, and 3rd and 4th at higher rpms. I also get the slacky play in the driveline if a hit the gas; I get a serious jerk. It seems like every manual trannny equipped vehicle I've ever had has been like this. I don't really get any clunks or anything like would indicate a tranny input bearing or CV joint. It's just hard to drive sometimes cause it's so jerky when hitting the gas, or letting off the gas; at low speed I even have to just shift to 4th so the jerkiness isn't so bad, like in parking lots and such.

 

[Ferb]

Driving my girlfriends '92 Mazda 626 i get that a lot. It's such a light car that it gets massive engine braking in low gears.

Just have to nurse it-- i think it's the nature of a 5-speed.

But if you want to talk about jerk, my father's new Mitsu Lancer Evo. sheeesh. Boost comes on so early you're lighting the tyres in parking lots all the time.

ferb!

 

[acranox]

My car does this a little. A jerk when I take my foot off the gas, and a jerk when I go back on the gas.
But I'm 99% sure that in my car, it's cause by the fuel cut off valve.
I drive an 87 Honda Accord. The fuel cutoff valve shuts off fuel while coasting to save on gas. And so when the engine is still cold, it hardly jerks because the cutoff valve doesn't start working until the engine is warm.

I don't remember having this problem with my Fuel Injected 94 Civic...the system was probably more intelligent than the carb on my Accord.

 

[eljefino]

A lot of the time it's loose motor mounts. They come from the factory pretty soft (for comfort) and only get softer. Many aftermarket companies have stiffer mounts; it's satisfying to put the power down and chirp the tires instead of having the engine bounce around.

 

[drm7]

What I interpreted as 'slack' in my F150 5.8l was really a bad u-joint. It would 'bang' when you backed off the gas then accelerated again. Felt like slack. May want to check yours.

 

[Drew99GT]

Well, I don't have U-joints, just CV joints (FWD), and they are in perfect condition.

 

[acranox]

quote:

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Originally posted by eljefino:
A lot of the time it's loose motor mounts. They come from the factory pretty soft (for comfort) and only get softer. Many aftermarket companies have stiffer mounts; it's satisfying to put the power down and chirp the tires instead of having the engine bounce around.

---

Right, I forgot about that. That's the second theory I have about my car....being that it's 16 years old I'm sure the motor mounts are in trouble. I'd really like to replace them, even with OEM units, but I'm sure it's a PITA job, or really expensive to have a shop do it.

 

[Drew99GT]

I've looked at my mounts, and they look fine; the rubber is still lookin great. That doesn't mean they are sloppy I guess though. Guess I'll take it in and have them checked, cause I ain't messin with this car no more

 

[Chris B.]

I asked this befor also. I noticed this in my 1996, 2000, and 2003 Silverados a manuel 1989 s10
and some time in my 2002 Camaro. It seem to be normal to have slack and depending on how you gas the engine cam take it up harder or smoother.

 

[Drew99GT]

Chris B, I tried searching for your post, but didn't find anything?

 

[Kestas]

There's a term for it in the automotive industry. It's called "tolerance stackup"... very important for transmission engineers.

 

[Chris B.]

Drew, It was a few months ago and now that I think of it I might have asked it over on LS1tech.com on the truck forum but can't say for sure, I'm sorry. I do remember talking to a few gentelmen that seem to know their stuff and said this was perfectly normal.

 

[Drew99GT]

Thanks Chris.

 

[geeeman]

quote:

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There's a term for it in the automotive industry. It's called "tolerance stackup"... very important for transmission engineers.

---

There's a term for it in the parking lot...

It's called "rubber-banding".

Some cars do it more than others...The cause?
Anything between the gas pedal and the tire that has a little bit of slop...

 

[Robbie Alexander]

Mine is AWe-FuLL
very hard in my truck.
It was bad when new.
All the dealers said it is normal for some of them to do that
After I went over 100K changing the fluid about five times
Then the dealer says It was a factory default in a part in the Rear-end... shoulda got it fixed under warranty (those jerks).
So I fill it with fluid and go 200K+++ and drain

Then I put a little cleaner in there to do a short flush and after about 13K the noise and feel got about, well much stronger... Did a couple short flushes, and am back on the extended drain... Same with the tranny on the fluids.

I am almost at 400K lacking a couple weeks or about 3K.

 

[Chris B.]

Drew, are you a member at LS1tech.com? If you are do a search in the truck forum under "transmission shifting" and you will have a few good things to read.