This is on my 1988 XJ-S V12 US spec. with 64K miles.
A few days ago, the car
​​​developed a whining sound that comes from the transmission, it can be heard in parking and in neutral with a steady whine, but once in drive, the whining increases with the rpm and some times, with the gear changes, it disappears for a very short period. The transmission feels fine and changes gears as always. This whining began suddenly, I removed 7 quarts of fluid through the dipstick tube (kind of brownish color) and replace it wit fresh Dex/Merc fluid but the whining continues.
I've read that the o-ring on the pickup tube can let air in and develop cavitation and this whining, but can the o-ring fail suddenly just by itself? Has any one had this issue on their transmission? If this is the case, changing the filter and making sure to install a new o-ring properly seated will solve this issue, but, I don't know if it will be as simple as that.
I don't know much about automatic transmissions and don't really know if this could be something else, like the torque converter, or even the transmission itself...
Any opinions?

TIA

Alfredo

 

The TH400 transmission does have a gear while in first, that's the way the gears mesh and is normal. However, whine when parked isn't normal. You checked the fluid level when it was hot, engine running and in park?

If the filter is original, an O ring could certainly crack and cause air to be sucked in. However, I would have expected a loss of drive in that case. I am really surprised you got that much out from the dipstick, I would have expected no more than about 4L to come out, that's a typical amount that is in the pan. Dropping the pan to change the filter isn't that difficult to do, just messy.

It can be common that when changing the filter, the old O ring gets left behind and when the new filter is put on, the old O ring gets pushed up into the transmission. That can case the filter to crack, as it will be forced into place by the bottom of the pan. I woudl be wanting to change the filter and inspect the pickup tube and the hole it goes into, make sure there isn't an extra O ring in there.

 

Thanks for your reply, I did check the level when hot and was between the two marks on the "hot" side. The 7 quarts were gravity drained with a clear hose about 1/4" in a 3 day period, almost drop by drop, left the hose all day and in the morning had to suction again, and fluid would start coming out again, as if the pan was filling slower than the hose was able to pull the fluid, I hope I'm been clear.
I will drop the pan after I drain the fluid agan (will take me 3 days to drain as much as I can) and hope to see a craked o-ring or something obvious.

 

Assuming it's the transmission and not the power steering pump, the 2 most common causes are a dirty (plugged) filter or a damaged o-ring on the filter tube. It's common practice in the transmission trade to install 2 o-rings on the filter tube to try to avoid the pump sucking air. If your transmission has a plastic filter pickup tube, these tend to harden and shrink with time and there are metal ones out there. Any GM T400 tube will work as long as it is for a passenger car (shallow) pan. Later pickup trucks had a deeper pan and longer pickup tube.

 

Tyee,
Thanks so much for your reply, I am draining as much fluid via the dipstick tube and will be dropping the pan to install a new filter and the o-ring in the pickup tube. I've read about the double o-ring, I wasn't sure about it but I think there is nothing to loose by doing that... I've seen the metal tubes and will probably also follow your advice...

 

Looks like you are on the way to fixing the problem. Remember that when draining the fluid there will still be quite a bit in the torque converter. Not sure how to gid rid of that. If the transmission hasn't been serviced in a long time that fluid would best be replaced.

 

For all you transmission experts. Why don't they put a drain plug in the transmission pan? Seems like such a simple thing to do to facilitate servicing.

 

Doesn't facilitate servicing and actually prevents it by presenting the option not to check or replace the filter. If you are at the point where you think the fluid needs changing then so does the filter and it is a good time to inspect the sumps contents which you cannot do with it in place or a drain plug.

If the fluid is burnt or bad then the transmission needs work anyhow, no point putting off the inevitable.

Only way to purge the torque convertor is to run the fluid through a purge machine, I don't think any Jaguar convertors had drains in them though some do - the juice isn't worth the squeeze - if you're concerned just change it out a couple of times which is a messy and horrid job ...

I bought a sump with a drain plug, it is still on the shelf.

 

Some have 'em.

My XJR/6 with the 4L80E had a trans drain plug. And the ZF transmissions have 'em as well, at least the ones I've worked on.

Cheers
DD

 

A number of Ford transmissions had drain plugs on the torque converter too.

 

A drain plug makes a filter change so much less messy as, obviously, the bulk of the old fluid is drained off before dropping the pan. Plus, a drain plug makes it irresistibly easy to freshen the transmission oil as a matter of routine servicing.

So, you drop the pan, clean it, replace the filter, add new fluid. Good. The drive the car a bit, drain and refill again. Repeat 3-4 times and you've got all fresh fluid. Then do a drain-and-refill every 10k miles or so to keep the refreshing the fluid. It takes only 10 minutes and, if nothing else, cannot possibly do any harm!


Take it off the shelf and install it on the car. The fluid changes will be much less horrid, I promise!

Cheers
DD

 

I will be dropping the transmission pan this week (have nevere done it before), and for what I've read, the biggest hassle is removing the transmission mount, other than that, it's just removing a few bolts and making sure the pickup tube and o-ring are properly seated. But I have read the option of permanently removing the collision bracket, it has been said that there is not really a need for it and if removed, you gain acces to drop the pan with out messing with the transmission mount, any thoughts?

 

I removed the bracket on my both V12 cars and nothing bad ever happened as a result.

Cheers
DD

 

Can confirm that neither of the two 1996 XJS with the ZF 4HP24 transmissions had a drain plug. I did purchase one with a plug from a scrap yard since some do come with the drain plug. Can't tell you why some have them and some don't....

 

Good plan.

 

I have a sump plug on the ZF transmission in my AJ16 4 litre. However, I no longer use it to drain the fluid.

I syphon the fluid out of the dipstick / fill tube before dropping the sump to replace the filter. There doesn't seem to be much difference whether I syphon it out or drain via the sump plug. I also take the approach mentioned by Doug to do multiple fluid changes.

Presumably, if one syphons the fluid out of a V12 auto sump first, it then makes the filter change considerably less messy as well.

Paul

 

Some do. My 94 12 with a 4L80E had a drain plug.

 

Quick tip to avoid a spill while dropping the pan: Put longer bolts at each corner. Lower the pan onto the longer bolts to leave a space for syphoning out the remaining fluid.

HTH, Dave

 

Update, I have my 87 up on the hoist and it has a deep (3") pan but I know I've rebuilt customers units that had a shallow (2") pan. The transmission has been rebuilt before I bought the car so it might not be original. The filters are the same, just the pickup tube and retaining bolt change.

 

An update and a question. I removed the transmission mount with no major issues, of course the rubber bushing (cotton reel) is gone... I have a new black rubber one from SNG, I hope it will last. The question is, how do I install this rubber bushing into the triangular mount, should I use a press and brute force? If so, what do I use for lubrication? Petroleum jelly, ATF, silicone grease, detergent?
And just to make sure, this all goes to the trash can, correct?
Tomorrow will drop the transmission pan and hope for the best..