possible gearbox problem?

[monda2]

Hi All

I have a problem with my girlfriends 91 civic si - auto, (done 230,000kms) when cruising, so light throttle whether its at 60, 80 or 100 kph, it feels like it (sort of - hard to explain) skips gears, the revs drop 200approx revs when this happens but its doesn't seem to change gear as such!

I have changed the gearbox oil with honda MTF, made a slight difference but not substantial!

Could it possibly the TPS? Is the gearbox on the way out, when accelerating its fine, only happens when cruising or feathering the throttle

Any help appreciated

Cheers
Ben

[bennjamin]

Fyi you should use honda auto gearbox fluid not manual mtf.
Your issue might be slipping inside - try going thru the D , D3 , D2 and L etc to try and replicate the same issue.

[monda2]

sorry my mistake i did use auto fluid, just changed my manual box with MTF was thinking bout that, good idea will try tomorrow

[rotary_snail]

Might be the lockup clutch in the torque convertor having problems.

[monda2]

Ok I tired driving holding it in each gear and it seems to be fine using this method so this issue only happens when its in Drive when cruising, could this be the clutch slipping?

[~Sp33~]

Sounds like a conventional automatic with overdrive working the way it was designed to.

It's not anything to be concerned about.

[monda2]

no overdrive on this though! doesnt feel or sound great, not to fussed though just would like to know whats going on as it never did it previously!
seems like a clutch issue!

[bennjamin]

so did u change with fresh honda ATF ? Remember you will need to flush it up to 5 or 6 times to fully remove ALL old fluid from the torque convertor

[monda2]

Benjamin

no didnt flush it, but did use fresh honda ATF

just read through in the DIY section, no one really explained flushing, someone said to put some cheap oil in , drive around for a week then drain and fill with the honda atf?

You suggested flushing it 5 or 6 times, using cheap oil? - fill then drain, fill, drain, fill, drain etc? with the cheap stuff then a final fill with honda atf? Is this what you meant?