krnluve24

Kindly need some advice.
Car has 170k miles and auto transmission bangs/clunks shifting from 2 - 3 gears at around 25 - 30 mph or so. It does not happen if I accelerate moderately or fiercely say from a dead stop to whatever speed all the way to the last gear. It only does it when I'm cruising in traffic at low speed and bangs as it changes from 2nd to 3rd with very little throttle. Usually I combat this problem by ease off the throttle before it shifts but it doesn't always help. This engagement problem only happens at this specific gear change, there are no other issues with the trans. Anyone has any ideas? Thanks.

I just want to add that the loud bang/clunk noise sounds similar to switching from park to reverse on a hill without parking brakes on...

slowcivic2k

When did this start? Is the transmission full of good fluid? Etc....


Diagnosing from an arm chair, it would sound as if you have a pressure release problem in 2nd gear. This would allow the transmission, for a split second, to operate in two gears at the same time. This is normally experienced with a slight deceleration due to the two gears binding up. Extra throttle in theory would make this less apparent, as more power is applied to overcome the binding, resulting in a more natural shift.

A stuck 3rd accumulator would also be suspect. Not likely, but relevant.

krnluve24

It has always done that since I got the car 30k miles ago and I drained and refilled the ATF once roughly 15k miles ago. The fluid came out pretty dark like it had never been changed. If this is a pressure release problem in 2nd gear, which component is causing this? I fairly hands on with cars but I never really worked a automatic before other than removing it from the vehicle. Thanks slowcivic2k.

slowcivic2k

Again, from an armchair, a bang is produced by the preceding gear, as the bleed port does not evacuate fast enough from the previous (2nd) clutch, resulting in two gears at the same time. At no point can the next gear be suspect unless the next clutch is shown to be leaking from its control circuit (IE applying when it should not have any pressure).

An engine mount or defective axle can be suspect as well, but given gear dependence, and again, from an armchair, is not likely.

crashomatic

I am having extremely similar issues as OP with my 1991 Accord with a fresh F22B and tranny swap. New axles and mounts were part of the swap. I have been driving this car for 21 years and only experienced a bang about once every two years when aborting a sudden heavy accelleration at high speeds when I suddenly let off the gas. Now I experience this bang thirty or more times a day under extremely gentle driving conditions.
This bang showed up with the swap
When driving with a heavier foot and positive torque there is perfect shifting but when gently driving with nearly no torque there is a very bad BANG when shifting from 2nd to 3rd gear, mostly, but sometimes happens from 1st to 2nd.
I also have aquired a hideous vibration after 68mph in the front that high speed balancing is not getting rid of.

The previous reply above this one caught my attention as well as OP's descriptions of what seemed to induce the bang.

The original swap was October 2016 and I just swapped the rebuilt original tranny that sucked bad with a JDM tranny that pairs with the F22b more appropriately. I was hoping this fresh transmission would take care of the bang but tbere was no change in this very bad bang.

​​​​​​​I hope someone understands and can help. I am very frustrated with this swap project.
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