Hi guys!

I have some problems with the transmission from our 67 Delta 88.
The transmission pan was very leaky and so I replaced the transmission filter and changed the fluid. There was no seal for the pan left :-)

But now, it is still leaking and I donīt know where the problem is.
I can imagine that the problem are the seals which are going from the transmission to the engine. I canīt explain better because my Englisch is not very well and I donīt know the English word for the seals I should replace.

Thanks for all your help!

Ben

 

Ben from what little I know about transmissions, I do know that the level is critical, and if it is "over-full" it will "burp" out the filler / dipstick tube.

There is a specific procedure to follow when checking the fluid level:

1) Trans / engine at operating temp
2) check while running
3) either in gear or neutral, I think N but it's important.

I'm sure someone with better knowledge will correct me if I'm wrong and also hint at another area.

I have 3 TH400 and all of them leaked at some point (and the wagon still does a tiny bit)

 

The dipstick tube is good place to look. It has an O ring or rubber grommet seal that might be bad. You could probably replace this your self.

The rear seal where the drive shaft connects at the yoke might be bad. You could probably replace this your self.

It could be the front seal where the torque converter rides. This is a bigger job and transmission would have to be removed.

Its possible the manual selecter shaft seal is bad. This is where the shifter cable connects to the linkage. Its like an O ring but thicker/larger. This is simple to replace also.

I would suggest that you clean the transmission very well, and place a clean piece of card board/corragation under the transmission.............wait for it to leak again to find the location. Make sure the transmisson is not over the full mark on fluid.

 

Assuming the case is not cracked, there are only a handful of possible leak sites. First and most obvious is the pan gasket. Next are the case penetrations - the manual shift shaft, the speedo cable, the kickdown electrical connector, the fill tube, and the vent tube. There is the tailhousing to case seal. There is the front seal at the converter and the pump-to-case seal, Finally, there is the output shaft seal. The converter and pump seals will both appear to leak out the bellhousing, so these may be tough to differentiate, but all the others are pretty well separated and easy to see. As noted, check for over-filled oil and also verify that the pan wasn't warped when reinstalled. It's very easy to overtorque the bolts and distort the pan.

 

Hi Guys!

Thank you very much for the answers. I try to figure it out and will respond.

What kind and brand of transmission fluid do you use? Are there any secrets?

Ben

 

I use whatever I have, I tend to buy Chevron or Shell products, hardly ever need to use any though that all 3 of mine are relatively dry underneath - took some doing but all in all, pretty dry

 

I had the same issue on my 66 Starfire. Changed the gasket and it still leaked. Mine ended up being where kickdown eletrical connector. It is on the drivers side about midway back, you will see two wrie that go into the tranny. The bad part is that you need to remove the pan again to get it off with out breaking the brittle plastic connector. I put new O-rings on it and it still leaked a bit after a few days on the lift, but after driving it the leak stopped. I did add some Lucas tranny additive, so either that or the tranny fluid heating up helped the o-rings swell a little and seal.

Another trick I learned is to use a hammer and dolly to straiten the bolt holes out on the flange. They holes will tend to suck in towards the tranny over time. I know you can just buy a new pan, but with a little less than 30 minutes in it, I had a good pan. I also used some rtv on both sides of the gasket and torqued it to the spec on the tranny seal. I tightened it to 100 in lbs then waited an hour to tighten it 125 in lbs. The seal actually said 120, but 125 was easier to see on the torque wrench...lol

 

Hi Jeff,

which kind of Chevron do you use.

I am really confused about the specifications from all the different oil types. Do I need a ATF or a Dexron oil? I imagine thats more easy to find the right one in the US :-)

For the last change I used a Castrol ATF TQ DIII. Was this OK or did a big mistake?

Ben