Yet another metric 200 question

mike britt · 10-02-2024, 10:56 PM

What causes the front pump seal to blow out. I just got this transmission and put it in my car and it blew fluid everywhere. The seal was out of the pump completely. I don't know much about the thing like who built it. I thought it was odd that the cooler ports were plugged.

Henrys Toy · 10-03-2024, 05:46 AM

Quote:

Originally Posted by mike britt

What causes the front pump seal to blow out. I just got this transmission and put it in my car and it blew fluid everywhere. The seal was out of the pump completely. I don't know much about the thing like who built it. I thought it was odd that the cooler ports were plugged.

Good morning Mike and to all,
Without knowing whether this trans is in a Stocker or a Super Stocker, internal pressure will push out the front pump seal. GM has a retainer for the front seal but you might need to check that the vent for the case isn't blocked or restricted. Depending on who actually built the unit and who's valve body has been installed will determine why the cooler lines are plugged. My McClay unit has a loop, my Leon trans is plugged. You might want to reach out to Mark Yac. that comes on this site, he might be able to give you some guidance. If someone in Mike's area knows of a good builder, maybe you could chime in here and get Mike some help.
Have a Good Day.

Respectfully,
Henry Kunz 1534 H/SA

Mark Yacavone · 10-03-2024, 12:11 PM

Mike, I've never seen a chronic case of seal blowout. Depends on how much pressure is behind it, and why. Is it a 350 converter conversion? Has the stator support been replaced? never used Loctite on a front seal but I suppose you could.
Most transmissions have an internal cooler bypass for cold climates. Usually one would completely remove the bypass and let the fluid make the loop internally. Not a big deal, if you don't want to run a cooler..I do, always. . One run ,every three or four hours? No big deal... Gas and go, turn 'em and burn 'em in a hot climate, late rounds? Different story..

ss3011 · 10-03-2024, 04:41 PM

Two ways to cure this problem. first is to make sure the converter bushing is in good shape and has the proper clearance to the converter neck, second is to open up the drain back passage that vents behind the converter seal . A 200 has a cast iron pump and the press fit for the seal is pretty robust. The 4L60 had an aluminum pump, and had a problem losing the converter seal , so a seal retainer was designed that pressed on over the seal to retain it, due to loss of press fit as the aluminum pump expanded as it heated up. Cast iron pumps don't usually have this problem. Your problem is probably caused by excessive leakage getting into the pocket behind the seal, so that clearance between the converter neck and the bushing is probably where that leak is coming from. Let us know what you find !

mike britt · 10-03-2024, 07:04 PM

This is a G/SA car that is not real fast. I did replace the seal and it was a tight fit. I also found that the converter snout looked burnt so I put a new converter in it. I will run it tonight and see what happens. It looks like the stock pump and maybe stator too in it.

mike britt · Yesterday, 04:33 PM

Ran the car last night and did not have any issue with front seal. We will see how it does at the national in Ennis. Hope it?s faster than the turbo 350 I just took out.

10-02-2024, 10:56 PM	#1
mike britt Member Join Date: Mar 2013 Location: Italy, Texas Posts: 148 Likes: 230 Liked 43 Times in 19 Posts	Yet another metric 200 question What causes the front pump seal to blow out. I just got this transmission and put it in my car and it blew fluid everywhere. The seal was out of the pump completely. I don't know much about the thing like who built it. I thought it was odd that the cooler ports were plugged.

10-03-2024, 12:11 PM	#3
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,642 Likes: 2,749 Liked 4,820 Times in 1,832 Posts	Re: Yet another metric 200 question Mike, I've never seen a chronic case of seal blowout. Depends on how much pressure is behind it, and why. Is it a 350 converter conversion? Has the stator support been replaced? never used Loctite on a front seal but I suppose you could. Most transmissions have an internal cooler bypass for cold climates. Usually one would completely remove the bypass and let the fluid make the loop internally. Not a big deal, if you don't want to run a cooler..I do, always. . One run ,every three or four hours? No big deal... Gas and go, turn 'em and burn 'em in a hot climate, late rounds? Different story.. __________________ Real life never quite adds up.... Jay Farrar

10-03-2024, 04:41 PM	#4
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 896 Likes: 67 Liked 232 Times in 109 Posts	Re: Yet another metric 200 question Two ways to cure this problem. first is to make sure the converter bushing is in good shape and has the proper clearance to the converter neck, second is to open up the drain back passage that vents behind the converter seal . A 200 has a cast iron pump and the press fit for the seal is pretty robust. The 4L60 had an aluminum pump, and had a problem losing the converter seal , so a seal retainer was designed that pressed on over the seal to retain it, due to loss of press fit as the aluminum pump expanded as it heated up. Cast iron pumps don't usually have this problem. Your problem is probably caused by excessive leakage getting into the pocket behind the seal, so that clearance between the converter neck and the bushing is probably where that leak is coming from. Let us know what you find !

10-03-2024, 07:04 PM	#5
mike britt Member Join Date: Mar 2013 Location: Italy, Texas Posts: 148 Likes: 230 Liked 43 Times in 19 Posts	Re: Yet another metric 200 question This is a G/SA car that is not real fast. I did replace the seal and it was a tight fit. I also found that the converter snout looked burnt so I put a new converter in it. I will run it tonight and see what happens. It looks like the stock pump and maybe stator too in it.

Yesterday, 04:33 PM	#6
mike britt Member Join Date: Mar 2013 Location: Italy, Texas Posts: 148 Likes: 230 Liked 43 Times in 19 Posts	Re: Yet another metric 200 question Ran the car last night and did not have any issue with front seal. We will see how it does at the national in Ennis. Hope it?s faster than the turbo 350 I just took out.