funky 3rd gear

[1990LTD]

I don't know what the problem is but the CV sometimes bucks a little..I don't know if that makes any sense. When I'm accelerating in (through) 3rd it pulls fine but if I'm cruising in 3rd with light throttle, that's when it happens - It sounds/feels almost like there's water or something in the gas.. but only light throttle cruising in 3rd. RPMs stay constant, no drops or spikes at all, and everything else about the car is normal. No lights come on in the dash.


I wish I knew how to better explain what's happening.

[Nathan in MI]

Does it do it only at a certain RPM, and do you ever experience it in any other gear than 3rd? I would try locking it in first gear and running it up to the RPM range where you've been experiencing it and see if it still happens. If not, I'm tempted to blame your torque converter.

[gadget73]

When was the last time the fuel filter was replaced? Tune-up parts in good shape/recent ?

[1990LTD]

nope, only seems to happen in 3rd, and i just drove for about 30mins without it happening, so its not a constant thing whenever im in 3rd. as far as tune up stuff goes, plugs/wires were new when i got it about 3months ago...fuel filter was replaced as soon as i got it. like i said, about 3 months ago...maybe time for a new one? oil filter gets changed with the oil regularly and the air filter looks great. what other stuff is involved in a tune up?

[1990LTD]

also, i dont recall it only being at a certain rpm but i will find out when i leave work in a few hours

[gadget73]

plugs, wires, cap, rotor, air filter, fuel filter are usually what I consider a tuneup. PCV valve if questionable, but that doesn't really affect how things run too much. If your motor is tired, it may be fouling the plugs though. Check the two rear plugs, those are the most likely to be oil soaked if theres a problem.

[1990LTD]

1500 revs...and only sometimes

[johnunit]

I'm having a VERY similar issue, if you're having this at 50-70kmh and it's a slight bucking. I hope it's not the same thing though, because that increases the odds it's a tranny issue, considering our engines are so different.

[1990LTD]

yep right around 60kmh. if i put it into od around 60 it'll shift and the problem goes away. doesn't do it at 1500 revs in 4th.

[1990LTD]

oh, and I dropped it into 1 and brought it up to 1500rpm and it's fine...but it wants to shift way too friggin early. hopefully the early shift point problem will be rectified once i get TV cable grommets in the mail from Scott....

[mrltd]

I had the same problem with my 91. I replaced everything but the transmission.



I ended up getting rid of it because of it.

[gadget73]

Early shifting and clutch chatter are both symptoms of low TV pressure. Could very well be the whole problem.

[1990LTD]

They're both symptoms? Good to know, thanks, gadget73 (I can't remember your real name haha). I am really hopeful that it's the whole problem..

[1990LTD]

Also, is 'clutch chatter' the proper term for what's going on? What exactly IS clutch chatter? I'm assuming it's either what my car has or is very similar to it...but mechanically, what's she doing?

[gadget73]

when I had mine screwed up, it bucked and hitched because the clutches were slipping. If you've ever driven a manual with a screwed up pressure plate or a really dead clutch that slipped, its kind of similar. Its the clutches engaging and disengaging rapidly because there isn't enough line pressure to hold them engaged. Its not good for the transmission at all, so I'd be getting that bushing replaced asap.