cobalt

So at 80k miles i just did a complete overhaul on my 04TT. Serpentine belt, plugs, filters differential, trans-axle and tranny fluid. Also gave it new brakes and tires> I figured I would be set for a while. Drove the car up to Vermont some 700 miles round trip. It was like driving a new CTT all over again.

I noticed as I got into traffic on the way home that I am now experiencing a slight clunk occasionally when it downshifts between 15 and 30 mph. This only happens on deceleration and it is not consistent but my wife said she could feel it in the passenger seat. Considering I did not have this before and if it is the valve body some speak of why would I have this problem with fresh fluid. Some have stated that fresh fluid helps this case it only stated after the fresh fluid. I used Porsche fluid and filter and temp was correct for overflow so what am I missing? .

wrinkledpants

Take a look at the bell housing and see if you're leaking fluid through that drain hole. Otherwise, I'd do the top-off process again and cross your fingers. I'm not a fan of Porsche trans fluid, but it in itself shouldn't cause downshifting harshness.

cobalt

Thanks no signs of leaking but will try the top off process again. I only used the Porsche fluid for the trans which cost enough. The others I used Mobil 1 75w-90. Everyone I spoke with said the OE stuff is best for the tranny. Other than this I was amazed how well it drives after 11 years. Other than being a royal PITA I am thinking fluid changes at less than 40k intervals from now on. These are worth so much more than market value for driving pleasure. Only down side is the dated Nav and no bluetooth.

hahnmgh63

I too would just say review the process. Start it up cold and then pull the filler plug, monitor the temp and start adding if it isn't dripping anything. Once full I would plug it by 35'C rather than waiting for 40'C. Most work better in cooler climates slightly over filled than slightly underfilled.

cobalt

Guess it is worth a try

Thanks

1BadAction

Cobalt, did you ever get this sorted?

cobalt

Funny you should bring this up. I did, it ended up being the cardan shaft support. I just replaced it with the Vertex upgrade and the clunk is finally gone. I guess I was lucky with the mileage on it. A lot of my friends had it fail at 50k miles. I highly recommend checking it if you hear any clunking.

The fix is overpriced for what it is but is far easier than replacing it with new or a rebuilt unit. The biggest problems were removing the bonded rubber from the bearing and repacking the bearing with the shaft still in the truck.

It was driving me crazy because the fluid was correct from the beginning.

Despite these problems I am amazed how a 12 year old truck can be as good today as it was when new.

endless_corners

Nothing like an outside problem to crop up while performing a bunch of other maintenance to throw you off the trail. I'm glad you figured it out and got it sorted.

cobalt

How true

Thx me too.

Km1.8t

Any vibration in the new mount? I have read some reviews that indicate a small vibration as the new mount is a lot more stiff than the rubber on the OEM shaft. I replaced the whole shaft and kept my old one, thinking of trying the mount next time. Glad you found your problem.

I have had my S for six years and it has been really problem free other that the known items that can be easily replaced. It is worth much more to me than anyone would would ever pay and is still a great driving car. Too bad it is not a Turbo though.

bweSteve

Glad to hear you got that worked out Anthony.

winter blues have me perusing RL on a daily basis now. 2-4 inches tonight too.

Guess it'll be another week+ before the roads clean up enough to take the 964T out for a spin again.

=Steve

cobalt

No vibration I have observed yet. It has only been driven a few hundred miles since I did the fix last weekend. I did take the time to make sure that the frame was not touching the body in any way other than the bracket it is affixed to. It is a tight fit and I can see how this could touch one side or the other and possibly send vibrations into the body. If anything it seems a little more precise when applying the gas quickly after being on the brakes. I was considering using the Colorado driveshaft rebuild for a little less $$$ but this won out. I have a bunch of projects going on.

Steve, We are getting snow now. The roads were finally cleaned of salt and now it looks like the turbo will sit for a few more weeks. Bummer.

1BadAction

I wonder if the GTS is different? Vertex says it works with the V6, S, and turbo S, but not the GTS. Might just be an oversight in their compatibility list. Right now mine isn't clunking or vibrating, but I do want to know what common quirks these things have so I can have a fix ready if they happen. Glad you found the problem.

cobalt

Good question. I would suspect they are all the same. I will be changing out the snow tires on my GTS next week I will check and see. I should have but never thought to check my cardan shaft while doing all the fluid changes. From what I can tell it was going for a while and it has a very small rubber ring that holds the bearing to the carrier. I would assume if you push and pull on the shaft and it gives any the rubber mount is starting to fail and should be replaced before it leaves you stranded. The new piece holds it solidly in place.

The car was running fine pulled in to get gas and as I pulled into traffic and got on the gas hard it let go and made this awful thumping noise. Interestingly if I was at speed under minor load it was fine. So I was able to limp it the 6 miles home so long as i had no hills and took my time accelerating.