348 Shifting Problem

Check your fluid levels to make sure that's not it. Warm up the transmisison for a bit. Shift at a normal pace, not speed shifting. Try double clutching to see if that helps on the up shift. Could be linkage, like cable binding if you are lucky. If not, yes, something internal. Use Redline trans oil, not the Shockproof stuff, though. Generally the transmissions do not fail if treated reasonably and maintained with fluid changes. They do not take abuse well, however.

 

Fro normal driving, double clutching usually takes care of that for me.

 

Shifting at 2k is too low, IMHO.

Kai

 

+1

thats your problem

 

Try shifting closer to 3k

 

What RPM are you now shifting at? Shifting lower than 3k is BAD for an engine as there are "minimum" rpm shift points for each gear - usually they fall around 3k for min.

 

I would agree that shifting at 3k or higher will help. Also it helps to to start your shift while the rpms are still rising. When the clutch is depressed all the gears in the box are slowed by the fluid drag and mechanical friction. If the rpms are dropping (off the throttle) when you start the shift it just makes everything slow down even quicker and makes for a poor shift. Ideally you want to disengage the gears just as the rpm falls off. You can actually feel that the gears have almost no load on them from either accelerating or decelerating.

On another point "double clutching" is used for down shifts not shifting up and it is also accompanied with throttle "blip" to raise the rpms. If your double clutching a 348 on the up shift........that's a bad thing.

 

When my 348 developed the clunk sound on shifting, it was due to significant wear in the clutch shaft splines.

 

I have to say that once everything is up to temp in my 348, I can shift to any gear at any rpm without any problems at all. very smooth all the time. I am going to count myself lucky.

 

I owned a 348 and it never "clunked" at any rpm on shifting.
and you didn't have to double clutch it to have it shift smoothly.

 

OK -- wasn't clear in my first post and admittedly skimmed the OP. Sorry, it happens sometimes I rarely have any reluctance from my transmission at any RPM when upshifting when it's warm, and I usually don't drive it until it's pretty darn hot. I will say that the whole car seems more fluid when it's kept on the boil.

I DO, however, find that normal, around town downshifts are much less "clunky" and faster when the car is double clutched. My car's previous owner confirmed this, and many other F-car owners have stated that double clutching smooths out their transmissions as well. I guess it depends on your car.

I think you and your mech are spot on in the last post, emailben. When I first got the car, I was terrified of the $10K transmission rebuild, but I learned that it likes to be really driven...under the right circumstances and within reason, of course.