Not too great of pics as it was getting dark and couldn't see crap but is anything to be gained from these pics. Cars been sitting a couple months and nice pool of red under it. Seems like it's mainly under the tq converter. You can see some fluid on the pan and exhaust. Any guesses of where it would be most likely leaking from while sitting? Was told it had a new trans put in 5-10yrs ago... clearly it had.

 

If its Red and on the convertor, is more than likely the convertor/pump seal, and/or the large o/ring that seals the pump to the casing.

The fact its sat a long time, I would clean it up with degreaser, and run it.

Some fresh fluid would do no harm either.

The TH400 does "drain back" when not used, and that overfills the pan, and the gaskets leak. The selector shaft seal is another weak point.

Look carefully, as the power steer is right there, and that fluid is also Red, and any fluid can appear to coming from one place, the place it drips from, where in fact it is "flowing on" from another.

 

I had a situation where my XJS stat for a few months, I had just topped the trans fluid before laying her up at my mothers place. When I went back 3 months later there was a huge pool of trans fluid under the car.

The converter had drained back and the fluid was coming out of the dip stick tube at the 1/2 way join. GM realised this on later cars (not XJS) that use 1 piece tubes with a dip stick that has a seal on the top.

 

I'm with Grant.


But, I would add a thought. Was there ever a dust cover over that big ol' converter?
If so, did you remove it to look? If so, was the inside of that cover covered in red ATF?
If so, yep TC seals. If reasonably dry, look elsewhere.


As in trans cooler lines.


Carl

 

I've never owned a car with a big old American th400... at first I was almost frightened when I looked and saw no cover under the converter. Ha I thought the pan was missing. There was no cover when I bought the car so no clue if there was fluid inside the case. I'm going to get some better photos tomorrow.

 

Unsure on the V12 application. But, the GM transmissions I've seen do have them.


The 4l60E in my lump is related to that TH400. It has a tin cover. But, It also came with a slick ribbed alloy unit.


I can almost see the flange on the bell housing, which is where a cover would be seated. See about four threaded holes ?


But, in practice, many run around bare. They can be a bear to refit. Could not resist the awful pun!!


In moderate conditions, it doesn't seem to hurt anything.


If you find so, a wrecker or trans shop can probably provide one.


Carl

 

I've never owned a car with a big old American th400... at first I was almost frightened when I looked and saw no cover under the converter. Ha I thought the pan was missing. There was no cover when I bought the car so no clue if there was fluid inside the case. I'm going to get some better photos in a little bit here.

 

Well I tried to get a few more pics of the trans today. Very difficult to see exactly what's going on. It appears that the main leaking is coming from the front of the pan more towards the drivers side. The bolts with red drips are in the front and left side. I know it's easy to be an armchair mechanic but any help would be appreciated. Am I looking at a bunch of money or a crapload?! Could it just be a gasket? If it was a tq seal wouldn't it be draining off the converter? You can see on the one photo the left cat looks like it's cooked a good bit of fluid. Thanks

 

Most likely the gasket has:

1) Dried up.
2(Bolts TOO tight, thus cracking that gasket.
3)The tin pan itself has the gasket side of the bolt hole "raised" due to overtightening, so simply bash them back so its flat again.

Simple, should be, BUT, if your car still has the "stupid" collision bracket at the rear, it becomes a PITA. I remove that bracket, then the trans pan basically drops down like any "normal" auto trans.

Some markets have the exhaust in the way, which can make lowering that pan fiddly at best.

Pre draining the fluid is aways a top idea, or you will be baptised in trans fluid. Some LUCKY owners have a drain plug, most do not, so suck the fluid out via the dipstick tube, then you will only be baptised with 1/2ltr as apposed to 4+ltrs.

I gave up on trans pan gaskets years ago. I replace the pan with a well placed bead of Hi-Temp RTV, and use 4 guide studs, and never have leaks again from that area.

OR

Some suppliers have a "rubber" material pan gasket, which is good.
Some suppliers have a cardboard type material, which is better than the cork that is normally supplied.

Looking at your snaps, I dont really see any oil from that convertor seal.

 

well that's fairly good things to hear. From getting under it and the pics, it looks like the gasket to me. I had a photo of the mount but deleted it...so not sure if I have the collision bracket still in place or not. Thank you for the tips on not getting too bathed in fluid. My buddy has an industrial pump so I can use that to get most of it out. If using a newer rubber gasket should I use some silicone gasket sealer or just install dry? Thank you again for the help. I'm glad I found this forum.

 

I use a "dressing smear" of RTV on any gasket.

This will help with the trans mount.

Jaguar TH400 transmission mount explained.pdf



#9 and 18 are the prime items of the collision bracket.

 

FYI, the special washer No. 28 and the spacer No 27 are shown in the WRONG order in this Jaguar diagram. The special washer goes on the rod first, THEN the spacer underneath it.
Greg

 

Forgot again, thanks Greg.

I have done so many of these I keep forgetting the drawing is wrong.

 

My 89 came with a cover over the bottom of the torque converter... Wouldn't want to miss that (personally).

 

Btw... Why are sump (oil pan) and converter both blue!? Higher stall possibility?

 

Cool, thanks... pretty sure I recall it being in place.

 

From what I was told a "new" trans and tq converter were installed before it was parked for about 5-10 years. For all I know it might be a beefed up trans.

 

Lots on input leading to focused diagnostics and repair plans.


1. Yup, I thought it odd that there was no cover on that converter. In the last pictures, I see the holes for the bolts. An oddity, when my son and I attacked an issue on my car, we found that the screws that fastened the converter to flexplate/flywheel were the same length and thread as those that fastened the cover over the converter. A whole other story there for another time.


2. Agree, blue and blue are probably the mark of the rebuilder. Stock, smooth shifting or a tad jumpy? To each his own.


3. The scratch on the trans pan suggests a smashed TC converter. Solved (?) by dumping it!!!


4. Were it my car, I'd get a replacement and install it.


5. Side bar. Neat little ripples on the TC. Move air and add cooling ? Heat is generated
in the converter. heat is the enemy of any auto box.


6. I'm with Grant. Two reasons. One, try the easies first. Leaky pan gasket quite likely.


7. Tis messy, but, I've done it and lessened the mess. Big pan under it. Kept the pan as level as possible during the process. If your shop floor is an issue, get a big tin pan to "protect" it. If not, lie mine, laundry detergent cleans pretty durn good.


8. I prefer the rubberoid gaskets. But, cork has and will do. Too tight on the screws is counter productive. The tin will be raised around the holes on the sealing flange. As Grant opines, a few taps and a back up will make them flush again.


9. I use a sealant to attach the gasket to the pan and keep it there as I get the screws started. In olden days, Permatex Red or even Indian Head gasket shellac did the job.


10. Fresh red fluid is good news as opposed to stinky dirty brown.


Your adventures also serve as a great tutorial in the archives.


Good work, keep it coming.


Carl

 

Thank you for the advice. I noticed the big scratch in the pan as well. Probably did take out the housing. I only got to drive it about a half an hour before parking it and from what I recall it had a bit of a "crisp" shift. Wasn't like shifting in butter. I might just try and find a new pan as this one might have gotten wonky from whatever hit it looks like it took. Whenever I do repairs I take a bunch of pics so hopefully I can help others

 

Appears it's still there...so do you just undo the 2 flat head screws and the the pan bolts or do you have to undo the whole thing?