Post #7 of this thread. He sparked a thought and then I remembered about the customers car.

 

Addicted2boost --

1) yes. The noise disappears switching from D to 4 with a fixed leading throttle position at 50+ or so to put the driveline under a bit of a load vs steady-state cruising on level ground at, say 70-80.

2) I went back up the list and saw the message from mglagleder. Looks like an ATF change is on my list for the next service. As I'm not equipped to do this, I have to debate whether to have the pan taken down with a new gasket and the filter/s changed/cleaned at the same time on a 30k-mile car with no leaks. (either option is far preferable to a transmission or diff replacement!) As an aside, I remember when I was changing oil on my '89 xj40 and my '97 xj6l, i would drain 3 quarts of ATF from the transmission at the same time so that every 3-5k I was slowly sending fresh fluid into the tranny. Can't do that as easily with a "sealed for life" transmission.

3) thank you, sir, for having far more memory cells than I do. This getting old stuff really sucks ... but driving Jags makes it at least tolerable.

Cheers.

 

It’s no problem. I try to help out when I can.

What I would do if I were you is to take the car to a well known transmission shop (NOT AAMCO), tell them you want a complete transmission fluid flush and the updated main pressure regulator valve even though your mileage is minimal. I also wouldn’t even mention the issue your having with the torque converter. Trust me, you don’t want to introduce another story on top of why your really there. Just say complete fluid flush and updated main PRV and you’ll be good.

 

Thanks, kind sir, for lending your expertise to this query and, I would suspect, many others. After finding a reputable shop I shall heed your advice.

Best wishes.

Eliot

 

If servicing the trans doesn’t help, try using 75W250 in the rear end while you source a new diff, definitely quiets it out down in the meantime.

Loss of pinion preload usually results in growl when you get off the throttle.

 

Addicted2Boost — I got sidetracked by a check engine light and feared it was the transmission. Just Left Bank running lean (vacuum leak, O2, whatever).

I found a highly recommended transmission shop. Before I enter the door, can you tell me if the flush and main PRV change will address the humming noise I get at the lockup point, or is it more in the preventive maintenance department for high pressure problems down the line like the A drum and valve body?

Further driving reveals the Humming noise at the lockup point is pushed off speed wise if I am in Sport Mode, but still appears at the point the transmission goes to 5th and begins looking for the lockup. My observation is the drop in rpms at lockup is pretty minimal ... though anything helps in the mileage department.

Thanks, sir.

Eliot

 

The flush will take care of the noise you have when the TC locks up. If they have the machine there, it’s actually called a transmission fluid exchange. “Flush” vs “exchange” both have the same set goals, to replace 100% of the fluid but with different methods to replacing them.

Having them replace the PRV is most definitely a preventative and a serious piece of mind in protection against A drum failure.

On a properly operating transmission, you should see about a 500 engine rpm drop when the TC locks up in OD above 45 mph. If you’re seeing more like 200 rpm’s, it’s likely that your TC clutch is slipping and causing that noise you hear.

This is the PRV from Transgo that will go in my wife’s low mileage 00’ XJ8 very soon.

 

Any updates on this?

 

My apologies for not having gotten back to you., Yes, there/‘s an update. No, there’s no change.

Backstory: I went to the trans shop everybody I know in the auto business around here said was the only honest, no up-sell, no doom-and-gloom operation in our county. I asked for the valve replacement and fluid exchange, and also asked for a filter change protectively. Because of their reputation, I did tell them about the noise inasmuch as I don’t like surprises. They did not try to sell me anything, but did very strongly wave me off Flushing the box. They said better to do a “drain and fill” which would take up to 8 liters. Ultimately, it took five. They test drove the car, heard the noise between 50-60. The owner said they listened to it on a rack and could not trace the noise to the transmission. He said he thought it might be a U-joint or something engine-related. One of the first things I did was have the U-joints lubed when I got the car home, began experiencing the noise and had it serviced.

I was delayed responding because I have been struggling with a check engine issue (lean both banks), and ultimately took it to a well-regarded independent, jag-only shop here in the DC area (Top Line). While diagnosing the CEL (don’t get me started on what they were asking for parts) they also drove it and heard the hum. They asked for two hours labor to diagnose it. I’m going to hold off a few months once I get it back from the CEL and pursue the noise at that point unless you have any further suggestions.

Thanks for following up and apologies again for not being more responsive.

Eliot

 

Once upon a time there was an extremely good Jag shop in Falls Church, across the street from the Volvo dealer. My old boss, a VP at TRW and later CIO for both DOD and Christians in Action, swore by them.

When you says you lubed the u-joints, I am guessing you mean the zerk fittings on both output shafts alongside the dif (?). Still, once on a lift and in gear, they should be able to hear the noise at about 1500 to 2000 rpm. Maybe exhaust vibrations; or diff bearings. If not, a tire shop needs to listen while balancing the tires while on the car.

 

I could understand to be wary of a full flush on say 130k mile transmission but certainly not 30k miles. Anyways, I’m assuming they installed the pressure regulator valve?

 

i don’t know about the ZF but flushing the early W5A580 is asking for trouble, especially if you use the torque converter drain plug

 

Why is that? I thought these were bulletproof transmissions in the R’s?

 

The early 580s have problems with the a little copper bushing falling apart and shredding the planetary gears, all the eastern european shop owners tell me to never drain the TC or flush just the pan and filter. The valve bodies in cars made <2000 can also have broken pressure regulator springs in the valve body which cause rough shifts.

 

The Don Beyer Volvo shop is still there. I used to have my 122S and 140/240/DLs serviced there on occasion. I am not sure what Jag shop might have been across the street, but there’s a place near Merrifield called London Auto that some have recommended. It does a fair number of jags but they do anything British. There’s also a joint just south of Springfield that does nothing but Jags called Top Line set up 25 years or so back by a woman who was a Jag Tech and which has built a pretty good reputation with folks in our area, and I also heard from a fellow now hanging out near Vegas who used them when he was TDY here. Top Line just made a check engine light go away for me.

Re the U-Joints, yes, I mean my local fellow who does the basic stuff for me put grease into the U-Joints via the zero fittings. I thank you for the other suggestions. I have found that the noise I hear is not present/or at least not as much, if I put the car into sport mode and go through the 50-60 range in sport. I’m not bright enough a diagnostician to figure out what that means. I do have to doublecheck that the noise isn’t present in sport at the point it finally drops into 5th and the TC locks up.

 

Yes sir, the new pressure regulator valve was put in, and I had them replace the filter while it was open. The report I got was that the pan magnets were pretty debris-free, which was good to hear.