Now I know this may be a common problem with the TP's, and I am well aware that many may say that I should just replace it with a manual, but this just isn't an option since my sister will be getting the car in the near future (she can't handle manual).

I've got a few problems with the transmission relating basically to the car losing a ton of power recently, and the transmission seeming to slip significantly while under load. There is also a fairly abnormal vibration while travelling at constant speed which feels like it is coming from the transmission. While accelerating onto a freeway with even a slight uphill, the car stays in gear 2 up until about 80k's and takes forever to get to that point. It never used to be that bad!

The issue was just starting to develop a few months before I got the new engine, but has significantly worsened since replacing the engine. I guess it is expected though, since it is a brand new engine, which has lots more power compared to the old one (which was totally stuffed). I have changed the transmission fluid (which was brown after about 2 months) and this has not changed the situation at all. The fluid is starting to turn brown again now too. TPS and all sensors are working correctly and are adjusted properly, as is the idle and everything else.

Anyways enough background - I am going to talk to a specialist tomorrow and see what they reckon, but after driving a magna with a completely stuffed engine, yet finding the car running way better than mine, I am fairly convinced it must be the transmission. How much might a new set of clutch disks cost to replace or to get the box rebuilt? I don't want to get a new transmission from the wreckers, as this one has technically only done about 150,000km and is fine other than the clutches it seems. Any suggestions?

Hmmm, not really any suggestions no sorry. I'm pretty much nearly in the same position as you, but my options are clear: manual rebuild.

Since working on my cheap as sigma, it's given me a lot of engine knowledge and knowhow, etc. So I'll be using the sigma while mine is off the road while I rebuild it, and since I've started my new really well paying job I might even turbo the wagon after I convert it.

But this isnt for a while, hopefully the trans lasts another 4-6 months in mine so I can get everything sorted out first.

Yours might even too, just depends what sort of driving your sister does and how much driving I guess. Otherwise maybe drop a whole recoed trans in would be the easiest?

Thanks for the replies... seems there aren't too many people in the forums these days who work the first gens any more! For the moment, I'm not entirely sure how my sister drives, as she hasn't even got her L's yet lol. I just want the car to be safe and run properly so it doesn't cause any problems to her. My brother is also learning on this car... so I guess it is a real learner's car now haha. Other than the transmission, the rest of the car runs perfectly. It idles smooth, it is good on the fuel finally, and has heaps of power to boot now (in my opinion lol).

Tried a second TCU and it behaves exactly the same. Now that the engine has worn in a bit, it is becoming a bit more clear cut that it is definitely the transmission. If I give it a few revs and it tries to change gears anywhere above about 3200 RPM it tends to sorta slip into the next gear (ie. it loses all power for about 4 seconds during the change and feels as if it's badly slipping... 4 seconds is way too long!). It seems to be across all gears too, but is significantly noticable going between second and third. Strangest thing that I still can't understand though is why the TCU is not producing any codes. Only thing I can imagine that would make that happen is if the slipping isn't bad enough for the TCU to register it as a problem :confused:

I did a stall test the other day, and it was just inside the spec range. It seems that in D it is about 50 RPM from being out of spec. It also mainly slips lots once the car has warmed up, as when it is cold it runs perfectly.

Yeah mine was similar when it was cold it would grab each gear better but when it warmed up it started to slip bad. When it's cold the Trans fluid is alot thicker so the auto wont slip as much. Mine got that bad that I couldn't go above 20km/h it would just be revving in first at 4000rpm and it wouldn't even change into second. I kept trying to drive it for a for a bit then it made a clunk and stalled. After that it would make a grinding noise whenever I selected anything except for park. I got it towed to a Auto Trans place they said there was heaps of metal shavings in the oil pan so I got a recoed one put in for $1600.00 A bit expensive but I just wanted it going again. If I had time and another car I would of got manual put in instead.

Warned ya that putting a new motor in blows up the transmission!

(Well, it's happened to me, but then again, what hasn't?)

Yeah mine was similar when it was cold it would grab each gear better but when it warmed up it started to slip bad. When it's cold the Trans fluid is alot thicker so the auto wont slip as much. Mine got that bad that I couldn't go above 20km/h it would just be revving in first at 4000rpm and it wouldn't even change into second. I kept trying to drive it for a for a bit then it made a clunk and stalled. After that it would make a grinding noise whenever I selected anything except for park. I got it towed to a Auto Trans place they said there was heaps of metal shavings in the oil pan so I got a recoed one put in for $1600.00 A bit expensive but I just wanted it going again. If I had time and another car I would of got manual put in instead.

Yeah sorta similar to mine although nowhere near as bad ;)

I was quoted about $1000 to get mine completely reconditioned, although that includes me having to source and pay for the clutches etc. too...

Part the reason the transmission slips more while warm too is that when cold the clutch material is a bit harder than when it has warmed up, so the clutches grip worse when warm.

And gav... yep I had a feeling I would start to loose the transmission soon with the new engine... i was just hoping it wouldn't get worse =\

I guess for now i'll just keep an eye on it and make sure it doesn't get too much worse. It seems to have settled down a bit recently, so maybe it still has a bit of life in it yet. :doubt:

I am happy to walk you through the box
so you can fix it yourself --
you already have the repair manual