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Author Topic: leaky transmission 85 Eldorado  (Read 1840 times)

Offline James Landi

  • Posts: 2376
  • 2007 XLR
  • Name: James Landi
leaky transmission 85 Eldorado
« on: October 20, 2014, 01:08:05 PM »
Just turned two hundred thousand miles and running fine,  my 85 Biarritz runs great except my transmission leaks oil at the very rear cover that appears to enclose the entire back side of the transmission.  Sometimes, when I use the car regularly, the transmission does not leak; however, if I leave the car over the winter, the oil loss is approximate four quarts.  I am nearing the end of the service life of this transmission? Any thoughts on repairs or concerns?   Am grateful for your consider option.  Janmes

Offline mgbeda

  • Posts: 623
Re: leaky transmission 85 Eldorado
« Reply #1 on: October 20, 2014, 04:48:58 PM »
I don't know much about '85 Eldorado transmissions, but, in general, a leak, even a bad one, is in no way a sign that the transmission is dying (unless you run out of fluid; that'd be bad).  Sometimes seals leak more after long storage because they dry out and shrink a bit.

-mB
-Mike Beda
CLC #24610
1976 Sedan DeVille (Bessie)

Offline bcroe

  • Posts: 3893
leaky transmission 85 Eldorado
« Reply #2 on: October 20, 2014, 06:31:26 PM »
Quote from: James Landi
  Just turned two hundred thousand miles and running fine,  my 85 Biarritz runs great except my transmission leaks oil at the very rear cover that appears to enclose the entire back side of the transmission.  Sometimes, when I use the car regularly, the transmission does not leak; however, if I leave the car over the winter, the oil loss is approximate four quarts.  I am nearing the end of the service life of this transmission? Any thoughts on repairs or concerns?   Am grateful for your consider option.  James

That TH325R4 trans is similar in layout to the 79-81 TH325 and 66-78 TH425.  You
need to look under there and see where the leak is.  One problem with these is the
chain cover on the back side, which can develop a leak at the bottom edge.  Best fix
isn't a cork gasket, but some of that form-a-gasket to glue it on.  Probably not possible
without removing the trans.  The bottom pan could leak when sitting a long time, as
the fluid can slowly drain out of the torque converter and overfill the lower section.  Or
any of the ports near the bottom of the trans.  The other big one is the final drive mount
facing the front of the car.  Generally all these can be fixed in the car, but not easily. 

The other issue is, all the soft parts in the trans are reaching their age limit.  Rubber
turns hard and doesn't seal.  The seals that can really damage the trans are on the
pistons that engage the clutches.  These can turn a simple "tune up" trans redo into
a "major overhaul".  The leaking outer seals are a hint at the situation inside.  If the
trans needs to come out I'd surely have it gone through before any serious damage
can occur.  Bruce Roe

Offline James Landi

  • Posts: 2376
  • 2007 XLR
  • Name: James Landi
Re: leaky transmission 85 Eldorado
« Reply #3 on: October 20, 2014, 06:59:07 PM »
Thank you gentlemen for your insights.  The hundreds and thousands of smooth shifts, thirty years of seasonal weather changes, and the limits of service life of these hundreds of parts are cause for real concern.   Would you recommend any of the national franchises for a major rebuild ?

Offline Dave Shepherd

  • Posts: 2422
Re: leaky transmission 85 Eldorado
« Reply #4 on: October 20, 2014, 07:10:47 PM »
Most likely not, do your homework here and find someone who has done this before and is confident doing r and i is not easy either.

Offline cadillacmike68

  • Posts: 3438
  • Still crusin'
  • CLC Number: 15823
  • Name: M Santos
Re: leaky transmission 85 Eldorado
« Reply #5 on: October 20, 2014, 11:04:32 PM »
James,

Seals, etc can be replaced without rebuilding the transmission. Don't let a trans shop talk you into an expensive but unnecessary rebuild. Find some place that can replace the seals. And try to at least get it out around the block twice a month.
Regards,
"Cadillac" Mike

Offline jsanford

  • Posts: 63
  • Name: Jeremy Sanford
Re: leaky transmission 85 Eldorado
« Reply #6 on: October 21, 2014, 12:30:22 AM »
At 200K miles it does not make much sense to go to all the trouble and expense of pulling the transmission and then just doing a re-seal. Ask around and find a good local shop that will take the time and care to do a quality rebuild.
Jeremy
Sacramento, CA
1981 Eldorado
2016 ELR

Offline 76eldo

  • Posts: 6648
  • CLC Number: 22443
  • Name: Brian Rachlin
Re: leaky transmission 85 Eldorado
« Reply #7 on: October 21, 2014, 07:49:20 AM »
If you think an additive like Lucas or Trans X might stop
the leak I would give that a try. 

I'd like to hear more about what you have done as preventative maintenance in order to get 200,000 miles out of the car.

Thanks

Brian
Brian Rachlin
Huntingdon Valley, Pa
CLC # 22443
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

Offline TJ Hopland

  • Posts: 10183
Re: leaky transmission 85 Eldorado
« Reply #8 on: October 21, 2014, 09:19:15 AM »
I can't remember if its the 425 on my 73 or the 325 on my 80 but one of them leaks out the dipstick / filler tube.   Its like someone mentioned earlier when it sits the fluid drains out of the converter which raises the level in the pan so it gets high enough to become a problem. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Offline cadillacmike68

  • Posts: 3438
  • Still crusin'
  • CLC Number: 15823
  • Name: M Santos
Re: leaky transmission 85 Eldorado
« Reply #9 on: October 21, 2014, 10:03:15 AM »
That's why you can't let it sit for 4 months. At least get it out and around the block.
Regards,
"Cadillac" Mike

Offline mgbeda

  • Posts: 623
Re: leaky transmission 85 Eldorado
« Reply #10 on: October 21, 2014, 02:46:40 PM »
Do not, no matter what, go to a certain national chain whose name I'm not allowed to mention.  (Hint: it rhymes with Spamco.)  They use unbelievably cheap, no-name parts and do shoddy workmanship.  I made this mistake on poor old Bessie, and went through four (4) transmissions before I finally gave up and redid their lousy work myself.  Not to mention they damaged the wiring harness and flywheel and losing the flywheel cover.  Absolute nightmare.  Thanks for reminding me.  Where's my nerve tonic?

-mB
-Mike Beda
CLC #24610
1976 Sedan DeVille (Bessie)

Offline bcroe

  • Posts: 3893
leaky transmission 85 Eldorado
« Reply #11 on: October 21, 2014, 04:07:24 PM »
Quote from: cadillacmike68
James, Seals, etc can be replaced without rebuilding the
transmission. Don't let a trans shop talk you into an expensive but unnecessary rebuild.
Find some place that can replace the seals. And try to at least get it out around the block
twice a month.


The seals on the clutch pack pistons CANNOT be replaced without complete dis assembly,
and they are the ones that will burn up the insides when the piston loses pressure.  Its
not the trans shop talking, its me who has rebuilt and installed 60s & 70s transmissions
in every one of the 5 cars I own.  Bruce Roe

Offline cadillacmike68

  • Posts: 3438
  • Still crusin'
  • CLC Number: 15823
  • Name: M Santos
Re: leaky transmission 85 Eldorado
« Reply #12 on: October 22, 2014, 12:01:33 AM »
Bruce, I'm not talking about internal problems, but rather front main seal, shift solenoid, speedo cable & rear seals, etc. These can be replaced.

If the transmission has internal issues, then yes some sort of rebuild is necessary, but that's not what was hinted at in the OP.
Regards,
"Cadillac" Mike

Offline James Landi

  • Posts: 2376
  • 2007 XLR
  • Name: James Landi
Re: leaky transmission 85 Eldorado
« Reply #13 on: October 24, 2014, 04:21:16 PM »
I can't remember if its the 425 on my 73 or the 325 on my 80 but one of them leaks out the dipstick / filler tube.   Its like someone mentioned earlier when it sits the fluid drains out of the converter which raises the level in the pan so it gets high enough to become a problem.

Hi Brian,   You asked about how I kept my 85 Biarritz running for over 200,000 miles... After replacing two 4100 engines that I babied, a very good friend "re-engineered" a 265 2 barrel Olds Cutlass engine into the space left by the original and two other 4100's.   Several nice surprises occurred as a consequence, not the least of which is that my wife and I can go on long trips and not worry about a massive engine failure.   I must add, though, that I just sold my 1983 for parts that had a GM rebuilt 4100.  This one ran reliably for 250,000 miles (that I put on the car) with nary a major issue. 

 

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