Hello, the TH400 transmission on my XJ12 started making a hissing/whining noise. Based on knowledge in the book, I decided to do a service in hopes that it was just the oil filter loose and the pump sucking in air. After dropping the pan, the filter was firmly in place but at the bottom of the pan I found two or three metal chunks like this..



I went for a test drive today after fitting the new filter and filling up with fresh Mobil ATF 220 (Dexron IID). The trans is still making the same whining noise in all gears, even in neutral and park (attaching a sound clip of the noise below - don't mind the other vibration sounds, my wheels were horribly unbalanced).

I didn't want to put too much load on the trans, but it also seems like it tends to slip under higher load, I went on the highway for a while and at 60 MPH the engine is almost at 3000 RPM, is that normal?

Either way it looks like this problem will cost a bit more than just new ATF and filter. Any suggestions before I accept the defeat and take it to a transmission shop?

 

Doesn't look or sound promising. Something inside the trans is breaking apart.

And 3000 rpm should be more like 80 mph so yes, I'd say you have some slippage; possibly a torque converter failing?

Cheers
DD

 

I;m with Doug.

That TH400 is strong, but when it does that, you need to bite the bullet.

At least there is plenty of knowledge out there.

Make SURE they flush the cooler lines, it is normal practice, but a few words asked never hurt.

 

Rebuild the trans, nothing else for it.

 

Thanks for the feedback everyone, normally I would agree that it's a no brainer to have the trans rebuilt. It's frustrating though because it was supposedly rebuilt by the previous owner, however I don't know the extent of the job so it may have been just a service as well.

Since the trans is no good, I am starting to get ideas if it isn't a good time for a change. I might look into a manual swap out of curiosity, but I assume there is no cheaper alternative to rebuilding the current TH400.

 

I'm no transmission expert but it sounds like the torque converter has given up. At 3000 rpm the car should be doing 80mph in top gear