I have an 87 Olds 98 with 130,000 miles. When I am driving in OD up a
hill, the transmission will start to chatter. I can usually relieve
it by shifting back to Drive. However, it even chatters some in
Drive. I changed the transmission fluid about 12,000 miles ago but
the fellow simply flushed and did not change the filter. I have tried
a couple of the additives but they don't seem to help. Any advice
will be appreciated.
are sure the trans is making the chatter to me it sounds like you got a
little of bad gas when you get bad gas and going up hills the values will
chatter put the high grade of gas in your car and see if that fix the
problem everytime i ised the cheap gas my car chatters
Question - if you push down on the gas pedal and force the transaxle
to downshift to third gear (while still in overdirve mode) do you
still get that chatter?
If the chatter goes away in 3rd gear but still in overdrive mode, I'd
suspect the 4th gear clutch has a problem. If you still have the
problem in overdirve range but in third gear, more likely the 3rd
roller clutch is not holding. The power flow is different between 3rd
gear in overdrive range VS 3rd gear in drive range: in 3rd gear in
drive range the 4th clutch is not applied and 3rd roller clutch is
effectively locked by the input clutch..
Neither is a cheap repair - either would require removal of transaxle
and a teardown (though the 4th clutch is the first clutch in the
gearset). . I'd first have the pan pulled and the filter assembly
replaced, since low line pressure (which can be caused by a partially
plugged filter) can lead to clutches slipping. Look CAREFULLY at the
pan for signs of either excess metal debris (which points to the 3rd
roller clutch) or excess friction material debris (4th clutch).
130K on a THM440-T4 before rebuild is actually not too bad
Hope this info helps.
I know it is bad form, but let me follow up my own message with an
item I forgot. If the problem is still present in 3rd gear in BOTH
ranges, then the 3rd clutch (different item than the 3rd roller
clutch) may be the cause.
BUT first thing: pull that pan, replace the filter and put some fresh
Dexron III in that transaxle. Fresh fluid and a filter that allows
full flow will do wonders.
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