News:

The ORG - No shonky business!

Main Menu

Transmission Death?

Started by brettj, 16 August 2009, 06:24 PM

brettj

I think I may have destroyed my 75 450SE today. On my way home from work I noticed that the car was starting to lose power and buck a bit. I felt this happen once before about a week ago and thought it was my fuel pump going bad. Well anyway, on the ride home today the car started to buck and then would not accelerate past 20 mph nor would it shift out of low gear. I was about 3 or 4 miles from home, so I just kept driving. As I drove the  tach was reading 3000 RPM unless I took my foot off the gas.

I made it home and shut the car off.  Found  a trail of transmission fluid in the driveway.  Opened the hood to find transmission fluid all over the valve covers, alternator, fan, coolant recovery tank and the air cleaner had sucked some fluid in as well. Under the car there is a large amount of transmission fluid in the passenger side wheel well.

So, did I damage my transmission driving the car in this condition? If the transmission died, why would fluid shoot all over the place?  Is it time for a transmission rebuild? Did I ruin my motor too?  HELP!!

oscar

Damn Brett!  Any clue to where the oil came from?  I'm guessing a transmission cooler line perhaps.  See if you can clean up the spill, top up the fluid and start it again and try find the leak first.  It might not be as bad as it looks since you haven't driven it for too long whilst it's sprung a leak.  Have a close look at the two rubber sections of hose that go to the bottom of the radiator.  They're available separately as replacements.
1973 350SE, my first & fave

brettj

I can't figure out where the oil came from. I've got to get it on a lift. The cooler lines were my first thought but the one  right under the radiator looks dry. Hopefully its something simple like that but with my luck its rebuild time! Rebuilding the trans is not something I really want to get into. Perhaps I should just sell the car.

geiz

You say the transmission fluid was also in the front section of the engine bay.
I think it's nearly impossible that it's coming from your transmission directly.
Like Oscar said, make everything clean and start it again seems to be a good solution.
(Maybe you have to refill with enough transmission fluid first)
Is it also leaking without the engine running?

TJ 450

It could also be a problem with the radiator core/transmission cooler... the fluid would get thrown around the engine bay when it hits the fan.

Oscar's on the money. 8)

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Papalangi

My '65 Mustang would blow transmission fluid out the dipstick tube if I ran it at high revs for a too long a time.  Have you got drips running down the underside of the hood?

Michael
'83 300SD, I'm back!  It's the son's new car (12/2020)
1976 450SEL, 116.033  Sold it to buy a '97 Crown Vic.  Made sense at the time.
1971 250C, 114.023
1976 280C
1970 250/8

brettj

What a mess! There is transmission fluid all over the engine bay. None is on the underside of the hood. I agree with Oscar that one of the cooler lines broke. The car has been transported to my mechanic. I tried to look under the car while it was on the flatbed and couldn't really see any broken lines. What I do know is that every bit of transmission fluid must have leaked out of the transmission. Its all over my driveway.

The transmission will operate correctly in park, reverse and neutral but will not work at all in drive. Perhaps that is due to the loss of fluid? My mechanic hasn't gotten a chance to diagnose the problem yet. Hopefully there will be some news tomorrow. I'm very concerned that I ruined the motor and transmission.

wbrian63

You shouldn't have harmed the motor even if you lost all your transmission fluid. The transmission is another matter. It has been my experience that losing just enough to allow massive slippage inside the transmission is worse than having a catastrophic loss of fluid where everything just stops working entirely. So long as you don't run it for a long time, a transmission without any fluid shouldn't be harmed - it takes fluid to engage all the clutches, bands, etc. The fluid also provides lubrication for the planetary gears and bushings, so running it without fluid for more than just a few moments is a very bad idea.

In general - if the transmission slips - that's bad. Just like riding the clutch on a manual-transmission car. Huge amount of heat buildup and resulting degradation of clutches and bands.

The bright side of having transmission fluid everywhere under the hood is things will clean up very nicely. It's got a lot of detergent in it, and will help to remove old caked oil, etc on almost anything it touches. On my 6.9, the suspension system fluid had been replaced with transmission fluid. There was a leak at the pressure hose connection to the pump, which got onto the accessory belts, where it got tossed all over the place. Where I've been able to clean, all it's taking is a quick squirt of brake cleaner and everything is spic-and-span. I'm even seeing dirt and grime "sliding" off the front of the engine...

Keep your chin up and hopefully the source of the leak will be something simple like a cooler hose, and all the car will require to be road worthy again will be a new hose and some additional fluid - and then a good underhood cleaning.

Regards
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V

brettj

Thanks for the encouragement! I did drive the car about 4 miles when the transmission went out just to get home. Hopefully that didn't destroy everything inside it. Still no word from my mechanic. I will call him in the morning. Usually no news is good news!

brettj

Good news! Got work from my mechanic and it looks like my transmission was not damaged. Oscar you were right. The high pressure hose burst. At the shop, they installed a temporary hose and  put in 5 quarts of transmission fluid. The transmission seemed to work well. So right now I'm waiting for new cooling line hoses to come in from MB.

I'll keep you posted.

oscar

Great news brett.  wbrian raised good points I never thought of particularly about operating with low fluid compared to no fluid.  Sounds like you were lucky enough not to stress the A/T for too long before parking it.

On another note, I'm trying that engine bay cleaning method you spoke of wbrian.  So far so good. It works better than engine degreaser that's for sure. ;)

1973 350SE, my first & fave

TJ 450

That was an excellent outcome. If the hoses are the early type without the springs, they can deform and restrict the flow as well.

I found that when I was working on my 6.9's transmission, my hands became spotlessly clean. However, washing the ATF off is another story. 8)

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

brettj

I did notice how clean the areas that were hit by the transmission fluid became in my engine bay even without wiping it down. The wheel well area even started to take on a shine!

wbrian63

The shine is nice, but it will track dirt like nobody's business. As I noted before, it responds very well to a shot of brake cleaner - don't even have to wipe it down.
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V