My differential started making noise so I checked the oil level and was surprised to find ATF in it. So I thought maybe I overfilled my trans and it forced it in. But after changing the oil and draining and refilling the trans, it still is making its noise. I was so upset I just parked it for tonight. Is the seal blown? Is my diff crapped out now? How hard to fix. I couldn't find any posts that dealt with this situation so any help would be appreciated.

Assuming this is auto trans? Differential dipstick on the passenger side, auto trans dipstick on the driver side.

How much fluid drained from the diff? How much and what type did you put back? And have you checked the condition of the fluid since the change?

 

Might also be good to know what year and how many miles on the car?

 

Generally once a diff starts making noise it is too late, the damage has been done, and there is no reversal without replacement.

Yes it is an automatic. It is a 97 Legacy wagon with the 4eat. I can tell it has been opened before. I drained at least two quarts from the differential. I was getting ready to do a full trans fluid change, but this beat me to it. Everything else seems fine. It shifts and drives good, but now has a whine like a banshee. Is this a fix I can do for not a lot of money. It has been 20 years since I've pulled a trans, but I'm poor so gotta be frugal. Or should I just get a trans from the junk yard?

Also I put a quart and a quarter of 80-90w in.

You don't need a whole transmission - the front diff can be removed and replaced without dissasembling the whole thing. You will have to remove the transmission from the car and then find a good used front diff to put on it. Shouldn't be too hard - they don't fail very often.

 

GD

You don't need a whole transmission - the front diff can be removed and replaced without dissasembling the whole thing. You will have to remove the transmission from the car and then find a good used front diff to put on it. Shouldn't be too hard - they don't fail very often.

 

GD

 

true, but where is the leaking seal and how hard is it to fix??

Sounds more like someone just filled it with ATF. I would imagine the seals are accesible but I'm not sure on that one. I haven't had to change one.

 

GD

Probably easier to just replace the tranny the trannies don't fail often either.

Yes but it will probably be cheaper to find a 4EAT at the junk yard (look for a car that already has the engine pulled) and then remove the diff and buy that. A diff is probably half the price of a whole tranny. I think my yards charge $45 for diffs vs. probably around $100 to $150 for an automatic tranny. If you haven't got the money then you have to sacrifice the time. My sugestion was simply to save him money on the repair - said he needed to be frugal.

 

GD

There is a seal between the front diff gear oil and the ATF via the input shaft. If it fails it could I suppose allow ATF into the gear oil. Of course it is quite possible a previous owner or shop put ATF in there instead of gear oil. If you drain the gear oil (well ATF that's in there) do you see a lot of shavings/metal stuff? If so it probably let the gears chew themselves up real nice since it needs the GL-5 gear oil for the extreme pressure additives which ATF doesn't have.

 

I think you guys are making this out to be simpler than it is. If the ring gear has worn, the pinion gear will also be worn. So that should be changed with it.

Then you have to deal with setting pinion depth and backlash correctly or else it will all happen all over again.

If you replace just the differential and ring gear, the worn pinion will make short work of the "new" ring gear and then you're in the same boat again.

 

 

I say drive it 'til it quits and replace the whole trans.

Sorry I didn't reply back sooner, crazy week. My sister lent me the money so I stuck in the shop. They just resealed it. They said the main shaft seal tube is what went. They also said all the sound was from the diff not having any gear oil but atf in it. I also had new CV's put in so that may help as well. Thanks for all the advice. I was about to go to the junk yard and get one there.

I'm glad you got a fix made. Let us know whether or not it still whines, will you?

 

As an aside, I do find it a bit humorous that so many are saying that an ATF, which is also a gear oil and will often (usually?) have protection levels of roughly a GL-3 to GL-4 level, has destroyed the diff. Humorous because so many run GL-4 gear oils in their M/Ts, which have the same hypoid front diff as the A/Ts have, and never think twice about it.

There is a seal between the front diff gear oil and the ATF via the input shaft. If it fails it could I suppose allow ATF into the gear oil. Of course it is quite possible a previous owner or shop put ATF in there instead of gear oil. If you drain the gear oil (well ATF that's in there) do you see a lot of shavings/metal stuff? If so it probably let the gears chew themselves up real nice since it needs the GL-5 gear oil for the extreme pressure additives which ATF doesn't have.

 

 

That is it. The shaft housing for the torque converter has seals that wear out. Nice research.

 

Wish more people would research and give answers that have merit instead of opinions that are uninformed.