How long does new ATF take to help?

[Ayrton]

I was curious. Some people have reported that minor automatic transmission issues get cleared up with fresh fluid. Does that normally happen right away or does it take a while?

Car is 95 Nissan Altima.

Whenever I first get on the throttle, from a dead stop, I have quite a bad vibration. It's primarily in my throttle pedal as a driver, but if you're a passenger you feel it as being in front of you and in the floor.

It does it pretty much every time you are coming from a dead stop unless you use no throttle at first from the stop and let the car get moving before gently pushing throttle.

However, if say there is a yield sign and you ALMOST come to a stop not fully, you can push throttle as hard as you want and it's smooth as can be. Only happens from dead stop.

I have changed lots on car. Engine mounts, struts/springs, both axles, control arms, etc. etc. All made the car drive beautifully but this vibration is awful.

I did an ATF change today, had not been done since about 40,000 miles ago. I put in Mobil 1 ATF again.

If it was going to help, would it have helped pretty much immediately?

Not sure what else to try. Many thanks for reading.

 

[oggb]

As far as I've ever seen if there's a difference to be made it's immediate.

 

[Donald]

If you had Mobil 1 in there before, it probably did not need new ATF at 40K miles.

In reality you really don't want new ATF to make a difference. If it makes no difference, that means your ATF was not too bad. If it makes a big difference then it was probably not doing the transmission much good.'

Bring it to an indy transmission shop for an opinion.

 

[Towncivilian]

Have you checked your engine and transmission mounts?

 

[Ayrton]

Originally Posted By: Towncivilian
Have you checked your engine and transmission mounts?


Yes, all four were replaced three months back. It was my first attempt at correcting the issue. The mounts were bad, but it didn't fix this.

Thanks for all the replies.

I do seem on to something with the transmission suspicion I guess. Thanks again.

 

[Towncivilian]

This probably won't help much, but try adjusting your accelerator & cruise wires - see page FE-3 of the factory service manual and EL-157 respectively.

 

[Roadkingnc]

Sounds like a bad inner cv joint

 

[hypervish]

It can be immediate on older cars, but newer cars learn how the transmission behaves and how you behave when driving it. So, if you want immediate results pull the battery cables, wait a few minutes and put them back on. That should reset the ECU and the learned values.

 

[mechtech2]

This still could be suspension or a misfire.
The trans may be fine.

Additives in a new fluid may help right away, or take hundreds of miles to get in the pores and be effective.

 

[HerrStig]

I don't think new fluid is the answer.

 

[Ayrton]

Originally Posted By: Roadkingnc
Sounds like a bad inner cv joint


Yes, this is what I always suspected.

However, again...

Both Axles, Struts/Springs all the way around, Tie Rod Ends, Sway Bar Links, Sway bar bushings, etc. etc. have all been replaced just in the past couple weeks.

Thanks again all!! Great information as always.

I guess there just won't be an easy solution.

 

[ac_tc]

Hesitating engine..
A bad cv joint..
It shakes as i understand in first gear so no lock up
or second shift, cant be tranny.

 

[RF Overlord]

FWIW, I changed the fluid on my recently-acquired 2000 Grand Monkey as I had no maintenance history on the car. Fluid looked decent, but the car was showing initial signs of the infamous torque converter clutch shudder. After the first drain & fill, the shudder was greatly reduced. After the 2nd D&F a week later, it was completely gone. Been gone now for over 300 miles. I'll do a third D&F when I change the motor oil again in 4,000 miles and I expect that will be it for a while.