Trans front seal leak

(Aristides Balanos) #1

Dear friends,

i have a slight leak from the front transmission seal, nothing serious, but the pan is wet and there is a drip on the floor every now and then,.
I was thinking to ad a Trans Leak Stop additive, with the hope that it will soften the seal, leave it for a couple of weeks and then change the transmission fluid and filter.
I am intending to power flush it so none of the old fluid stays inside.
Does this stuff work or will I do more harm than good ? I have never tried it before.
Any preferred brand or product ?

Thank you,

(Paul Wigton) #2

Likely won’t hurt, though, I’ve seen fairly dismal results with it.

(Frank Andersen) #3

Don’t think you should start now, Aristides…:slight_smile:

Honestly; ‘a drip now and then’ is neither here nor there as long as the level is maintained. Or are you, against all odds, expecting the additives to be a permanent solution…?

xj6 85 Sov Europe (UK/NZ)

(Jochen Glöckner) #4


as much as I support your proven penchant for perfection; in this case I both doubt that a full rebuilt is warranted to replace the offending seal and that any mechanic-in-a-bottle will help.

Though it may be deaf advice at this time of the year - I bet the seal would regain its properties with extended use of the car; could it be that it just has started to get dry and hard with lack of exercise? Southern France should at least be salt-free. Maybe you take the chance for an extended run over the week end?

Good luck


75 XJ6L 4.2 auto (UK spec)

(Carl Hutchins, Jr. ) #5

My vote is “No”, and like Jochen I understand and admire Aristides bent for perfection.

I did it once. but, only part I. No swap out the old fluid and filter. I got some more miles, but the leak returned, big time. But, I had given the IHC to my son. so it was his to resolve…

Carl ….

(Aristides Balanos) #6

Thank you gentlemen for your responses.
I see your point, I think I will leave my perfectionism pass on this.


(Pete55Tbird) #7

My experience with transmission SNAKE OIL was as follows. I owned a 96 Pontiac Bonneville that I bought new. 3.8 V6 4L60 A/T. After 15 years or so it developed " morning sickness". This means until the fluid temp in the transmission warms up and softens the rubber seals on the various transmission parts too much pressure
is lost and you get delayed gear engagement or no gear engagement. The snake oil softens and swells the
seals and restores normal function until you get a chance to either fix or sell the car.
I used Lucas Trans X and it worked as advertised. I kept the car almost 2 years after adding the additive.
I STRONGLY ADVISE AGAINST power flushing any A/T as the chances of crap being dislodged from inside
and ending up in the valve body are too great.
If it drips get a drip pan. Pete

(Carl Hutchins, Jr. ) #8

I “cured” morning sickness in the Mopar Ttorqueflit
used in my 79 IHC Scout II. Dropped the pan and fond the filter screen almost clogged with a jelly like goop. I replaced it and toped off the fluid. It was a messy job. Only “good” part was the high ground clearance. No jacks, ramps or stands needed, just roll under!! I could do that with a degree of alacrity at the time. That time gone…



(Aristides Balanos) #9

Advice duly noted…

(Aristides Balanos) #10

Same same with my Range Rover… Put it in high possession and just roll under.
Why didn’t Jaguar think of that?

(tony) #11

If you fully drain & refill the trans 3-4 times, that greatly purifies the fluid

A power flush conducted by AT pros uses ~15L on a large trans anyway

even a power flush, you still have old & new fluid mixing in the pump & torque convertor.

I recently did repeat drain & refill cost about $120 in trans fluid, calculate ~98% purity

(Frank Andersen) #12

It basically swells the seals by dissolving them, Pete - leaving the problem for future owners. And ‘snake oil’ works equally on all seals - whether they are good or bad. I’d rather live with an external leak…:slight_smile:

On the other hand; an expensive box overhaul will otherwise be required. On the second other hand; morning sickness may have various causes - as Carl implies…

xj6 85 Sov Europe (UK/NZ)

(W. Schuster) #13

I had my trans. leak regularly, especially when it was standing around too much,
since then I only fill my trans. case to about 1/4 inch over the bottom dipstick and it stopped
the leaks.
Mine leaks because the oil flows back into the pan when sitting around.

(Pete55Tbird) #14

Good morning Frank. A whole generation of GM cars sold in the US from the late 1980s well into the early 2000s have or will experience “morning sickness” You start the car on a chilly AM and
when you put it into gear NOTHING, No movement. The various seals are harden until the A/T
fluid warms up, soften the rubber and seals.
In a perfect world you would have car towed to the dealer and have the transmission overhauled.
This could cost $3500 and UP. Or buy snake oil for $7 and drive your beater another 2 or 3 years
at which time it will have serious rust issues and be junked. This is what is called "A NO BRAINER "

(Frank Andersen) #15

Or fluid expands to the useful level as it heats up, Pete…:slight_smile:

‘Morning sickness’ is a very rear topic in this forum - and with an external leak I would hesitate to use additives to cure that. My point was just to exhaust other possibilities when a box fails to perform…

xj6 85 Sov Europe (UK/NZ)