Pretty sure my Trans Am needs a new rear main seal

Crashnburn

Crashnburn

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Crashnburn
And not the kind that eats fish. When I bought the car about 5 years ago, Tony, my mechanic said it would eventually need to be replaced. I’ve kept it under control with an additive that makes seals swell but it’s not working now. The car goes through a quart about every 100 miles.

He’s not anxious to replace it because it’s a lot of work to pull the engine. There are much better seals than the original rope seal, so replacing it should be one and done.

What I like about Tony is he’s not anxious to do a big ticket job. I’d say he does good work, he has a 3 week backlog. Also, except for one time, the Firebird runs better when I get it back than it did before the problem happened. And he fixed the problem that one time.
 
I meant rear main seal. That’s what happens when I type with my oversized fingers.
 
Crashnburn said:
The car goes through a quart about every 100 miles.
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A quart every 100 through the rear main seal.


Just saying in California your neighbors may drop a dime on you...

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In California, any significant release or threatened release of a hazardous material requires immediate reporting by the responsible person to the Cal OES State Warning Center (800) 852-7550 and the Unified Program Agency (UPA) or 911. The UPA may designate a call to 911 as meeting the requirement to call them.​
 
I meant rear main seal. That’s what happens when I type with my oversized finger
 
What year, and which engine? I replaced a couple of them while the engine still on the car, but it can be very frame and engine specific.
 
Can't he just drop the transmission and do it? Not that it's tons quicker than just pulling the whole thing out, but it should save a little time/effort.
 
PaulS said:
Time for a new car. What caused the seal to fail??
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Rear seals are sometimes more of a consumable item on older push-rod engines. Some try to replace the rope-style seal with a one-piece viton seal, but I'm not convinced that one is better than the other.
 
Yanking the engine isn't THAT big of a deal in all but the most modern firebirds, although it does suck just for a seal. I'm guessing it's a legit Pontiac engine as I believe they used rope seals right to the very end in 1981. If it's a second gen like mine, you can't get the oil pan off with the engine in the car.
 
You said rope seal. 1989 Pontiac T/A with Buick Turbo V6?

You can drop the pan and pull it out or push it forward to uncover the rear main cap. When you pull the cap off, you can either grab the upper seal with needle-nose, or if it’s really bad, use a short length of copper wire to push it out. You want a two-piece rubber/neoprene seal. Clean the seat with solvent, put some RTV on the upper half, and slide-push it in (might need to have someone turn the crank). Don’t put it flush, offset by about 1/8”. Tiny dab of RTV on ends, then a very thin stripe on the cap parting line. Reassemble. I’ve done this twice (at least; on different vehicles, lol).

I believe there was a good write up on BuickV8.com

Edit: here it is
www.v8buick.com

BOP 455 Rear seal Install- Step by Step

I have had a few folks ask for this, and don't mind sharing. Once again, as I mention in every "how to" I post.. this is how I do it.. and it's been...
www.v8buick.com www.v8buick.com
 
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Crashnburn said:
And not the kind that eats fish. When I bought the car about 5 years ago, Tony, my mechanic said it would eventually need to be replaced. I’ve kept it under control with an additive that makes seals swell but it’s not working now. The car goes through a quart about every 100 miles.

He’s not anxious to replace it because it’s a lot of work to pull the engine. There are much better seals than the original rope seal, so replacing it should be one and done.

What I like about Tony is he’s not anxious to do a big ticket job. I’d say he does good work, he has a 3 week backlog. Also, except for one time, the Firebird runs better when I get it back than it did before the problem happened. And he fixed the problem that one time.
Click to expand...

Don' t know the Trans Am, but pulling an engine is not as ominous as it may sound. You can do it yourself if you have the luxury of working on it over several days.
 
SoonerAviator said:
Can't he just drop the transmission and do it? Not that it's tons quicker than just pulling the whole thing out, but it should save a little time/effort.
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That was my thought, if a Manual Transmission is a great time to put a new clutch in it also.

But I know nothing about trans-am, have just replace a few clutches and seals.

Brian
 
ElPaso Pilot said:
A quart every 100 through the rear main seal.


Just saying in California your neighbors may drop a dime on you...

Logo-Header-Main.jpg
​
In California, any significant release or threatened release of a hazardous material requires immediate reporting by the responsible person to the Cal OES State Warning Center (800) 852-7550 and the Unified Program Agency (UPA) or 911. The UPA may designate a call to 911 as meeting the requirement to call them.​
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That place is literally a hand grenade toss stones throw from where I work.
 
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It’s a 1981 TransAm with the Pontiac 4.9L engine. 3 Speed Automatic with torque converter lockup.
Naturally Aspirated

(The only Turbo I know about for this car is the 4.9L Turbo)

It a Special Edition like the Bandit sans T-Tops.

Too many memories with my wife to sell it. If I wanted to get rid of it I could drive it to a car dealer and finding a buyer would be like shooting fish in a barrel.
 
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Any engine old enough to have a rope seal in it should be easy to R&R so the seal can be replaced, even for an amateur working on it in their driveway. If you're dumping a quart of oil in the car every 100 miles, I bet the undercarriage is an absolute mess.

Pulling the engine to replace the seal may also be a good excuse to make some other improvements and wash the engine bay at the same time.
 
Crashnburn said:
It’s a 1981 TransAm with the Pontiac 4.9L engine. 3 Speed Automatic with torque converter lockup.
Naturally Aspirated

(The only Turbo I know about for this car is the 4.9L Turbo)

It a Special Edition like the Bandit sans T-Tops.

Too many memories with my wife to sell it. If I wanted to get rid of it I could drive it to a car dealer and finding a buyer would be like shooting fish in a barrel.
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Cool.. Black with snowflake wheels? My first car was a 1980 turbo trans am Indy pace car ed. I still have it, but it hasn't run in years. I think I mentioned in my panther thread that it burned all my money when I was in high school, but it was a lot of fun.

It was leaking maybe half as much as yours when I got it; pulled the engine to replace the seal and discovered all the bearings were grooved, so I had it rebuilt. I probably only put 10k miles on it before it was leaking again.

It's on the short list to get running again and get advertised for sale. Who knows maybe I'll fall in love with it again when I get it running, but I think I'm ready to let it move on to someone who wants to restore it.
 
Make sure you've checked the obvious stuff, like smoke coming out the exhaust, or plugged pvc system. 1 quart per 100 miles is a lot.

Those are cool cars. I had a buddy who had a late 70s Trans am with the 6.6 and manual transmission. That thing was scary fast. He worked as a police dispatcher and would blast through speed traps at about 80 in the city. Fun car.
 
FWIW ... many times the rear seal is leaking because the rear main bearing is worn and needs to be replaced. If you're going that far ...
 
mondtster said:
Any engine old enough to have a rope seal in it should be easy to R&R so the seal can be replaced, even for an amateur working on it in their driveway. If you're dumping a quart of oil in the car every 100 miles, I bet the undercarriage is an absolute mess.

Pulling the engine to replace the seal may also be a good excuse to make some other improvements and wash the engine bay at the same time.
Click to expand...
On the bright side, leaking that much oil helps keep the undercarriage from rusting!
 
Crashnburn said:
It’s a 1981 TransAm with the Pontiac 4.9L engine. 3 Speed Automatic with torque converter lockup.
Naturally Aspirated

(The only Turbo I know about for this car is the 4.9L Turbo)

It a Special Edition like the Bandit sans T-Tops.

Too many memories with my wife to sell it. If I wanted to get rid of it I could drive it to a car dealer and finding a buyer would be like shooting fish in a barrel.
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I'd love to see a picture.
Of the car... not the dealer, or the fish.
 
Zeldman said:
Don't know what the problem is. I mean add a quart every 100 miles and change the filter once a year...
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Reminds me of a joke. Went something like this. Guy gets a termite inspection. Inspector says your house is clear but there are termites in your wood pile. When that’s gone they’ll move to the house. We should treat the wood pile. Guy says how much will that cost. Inspector gives him the price. Guy says I think I’ll just buy them another cord of wood.
 
I’d probably be inclined to engine swap it with a drivetrain that’s more inspired and more interesting to drive. As overdone as it is these days, it’s hard to beat an LS swap. Fantastic torque curve, lots of power, better mileage, and starts every time you turn the key. What’s not to like?
 
Ted said:
I’d probably be inclined to engine swap it with a drivetrain that’s more inspired and more interesting to drive. As overdone as it is these days, it’s hard to beat an LS swap. Fantastic torque curve, lots of power, better mileage, and starts every time you turn the key. What’s not to like?
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Standing in front of the judge? lol
 
unsafervguy said:
easiest solution is pull the motor and replace it with a 6.6 with a B&M low rise blower.......
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But the cooler solution is a 6.6 with a really big polished blower sticking up through the hood.
 
SoonerAviator said:
No blower through the hood, it would impinge on the screaming chicken on the hood. Turbos are a better solution.
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I'm sure a nice custom solution could be devised for that. Pinstripers can do amazing work.
 
Call me old fashioned, but a second Gen bird with a shaker needs a NA Pontiac 400 or 455, with the holes on shaker cut open. That sucking sound as the engine gulps air, fuel, & money is half the fun.
 
Jim K said:
Call me old fashioned, but a second Gen bird with a shaker needs a NA Pontiac 400 or 455, with the holes on shaker cut open. That sucking sound as the engine gulps air, fuel, & money is half the fun.
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A worked-over 455 is the answer. Enough torque to twist the frame in half, lol.
 
Drop a crate hemi in there with a Tremtek 6 speed and quit screwing around. The wife will complain.... until that first drive.
 
Pictures are coming up. My wife loved everything about the car but the AMUs I poured into it. Unfortunately, the CoVid jab killed my wife. California Air Resources Board (CARB) puts the cabash on dropping older engines into the car and 1979 was the last year of the Pontiac 400. Also, the chassis is engineered for the low deck 301 to save weight.

I’m surprised I have such a leak. The previous owner overhauled it not so long ago. Maybe they didn’t get a good seal then. I had at least 40K more miles on my Firebird Formula 400 and never had a problem with that seal. It had a 4 speed manual with a Hurst Shifter and a racing clutch. The PosiTrac was standard. I miss its acceleration.

The shaker hood was designed to allow a higher rise carburetor for the higher displacement engines. Sort of gilding the lily for this car.
 
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