Mopar Muscle Association UK

Hi All - Happy New Year

My 75 Coronet (318 auto) has a leaking gearbox, I originally thought it was just a few drips, but I recently filled up with trans fluid, only to discover it had spilled its guts all over the driveway (and down the drain).

Now I hadn't even driven the car (due to a knackered battery), so was wondering if anyone can give me any pointers where it could be leaking from/what to look for?

I also replaced the battery hoping to start the car, but now it doestn't fire up man, it just gets better....

Any advice would be appreciated - I am on a real tight budget, as my Charger should be ready in June and I still need to pay for the remainder of the work on it!

Damn - why do I have such an expensive hobby

Common leaks are from the pan gasket, The dipstick tube seal, The gear selector shaft seal, the tailshaft seal, and the input shaft seal.

If it dumped out very quick I would suspect the selector shaft or the dipstick seal.

Hi Dave

it dumped out most of it overnight.....

I'll have to get under the car at the weekend, clean it all up and see what I can find.

Are the seals easy to replace?

Replacing the dipstick seal is a piece of cake, the tailshaft seal is not too much of a problem, you need a highly trained leprechaun to get the selector shaft seal replaced with the gearbox in situ and I'd rather not talk about the input shaft seal

re; filling trans, optimum level and filling. Does the fluid need to be warm or hot after running for a few miles before filling, or will idling do?
Got a slight weep on mine somewhere that I`m trying to identify. Must finish deGunking underside of 30years of grime

ive done the input shaft seal twice on diferent vehicles , i also had one that would dump fluid if it was left for a couple of weeks without being used but lost none when it was in regular use. it is a pain to do.

Neil. It has to be fully warmed up, been used in all gears, and idling in neutral when you check the level. Get yourself one of those long flexable funnels to top it up without making a mess.

A lesson i learned: dont overtighten sump bolts!!!!
This distorts the pan an it'll never seal again unless carefully hammered flat again
If unused for a while the cork gasket will dry out an just stark leaking for no apparent reason, prompting the uninitiated to tweak the bolts a coupla turns. Then a month later, same again. Then again.... then you take the pan off and learn that lesson

I personally prefer the rubber gaskets to the cork.

Ivor,
I'm confused! Whats the big deal with replacing the input shaft seal? I know books have a habbit of overstating the ease with which some jobs can be done, but a book I have (which is excellently written and easy to follow) reckons its a straight forward job (albeit with the engine out). Apparently its just a case of removing the torque convertor, removing the old seal and using it to drift a new one into position. The book (How to Rebuild Big Block Mopars) reckons this seal should alsmost be done as a matter of course if the engine is out - even if the seal isnt leaking. Did you suggest its a pain BECAUSE the engine must come out?

My engine is out at the moment, and the seal isnt leaking. If its a swine to do any way I will leave well alone.

Appologies if I have over simplified this job, but its the way the book put it accross.

Replace the seal Clivey or you may find it leaks after you put the engine back in.

It is a VERY easy seal to replace. Don't pay any attention to Ivor. He is as mad as a box of frogs.

has your speedo drive started to come out of the box?

this will emapty a certain amount of oil onto the drive.


Daveg

I think it was the taking the engine/box out bit that ivor was refering to.

Preciseley James...now if Dave can change the input seal with the engine and box still in, I will be impressed.

Mad? Surely not?

Well if your going to talk in riddles a man like me with only little brain is bound to get confused!