Transmission Fluid Change
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Joined: Oct 2009
Posts: 80
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From: East Longmeadow MA
Transmission Fluid Change
I have a question for the people in the know.
I have a 1990 convertible/automatic and am about to turn 30K on it.
I was considering changing the transmission fluid and filter. I was considering going using synthetic and was told that I should reconsider. I was told that doing this may loosen up any film that may internal in the unit and cause it to fail resulting in a new transmission.
Would this happen if I did this even with new conventional fluid?
I was told that if it is not burnt smelling to leave it alone.
What do you think?
Thank you for the suggestions.
I have a 1990 convertible/automatic and am about to turn 30K on it.
I was considering changing the transmission fluid and filter. I was considering going using synthetic and was told that I should reconsider. I was told that doing this may loosen up any film that may internal in the unit and cause it to fail resulting in a new transmission.
Would this happen if I did this even with new conventional fluid?
I was told that if it is not burnt smelling to leave it alone.
What do you think?
Thank you for the suggestions.
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 763
i have done full fluid flushes on several corvettes and never had an issue. i've done it on my 85 and the original 700r4 has around 150K miles on it, again, no signs of issues or problems. i've also done a full flush on my 90. i usually do a full flush around 100Kmiles, but a general transmission service every 30-40K miles. personally, i would drop the pan, replace the filter and an appropriate amount of the recommended fluid you will hear stories of people that flush a transmission and shortly after experience a transmission failure. some of this can be attributed to urban legend, and the rest attributed to transmission problems prior the the flush. BTW, i've done full flushes on several buicks, and a gmc sierra that i've owned - again zero problems.
Melting Slicks
Joined: Mar 2008
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From: Delta B.C. Canada
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The trans fluid is now 23 years old. Suction out as much as you can via the diptstick tube. That way you won't have all the fluid pouring out of the pan onto your floor when you loosen it. Then drop the pan, change the filter (make sure it's properly seated), and top back up with conventional fluid.
Since it's a vert, you'll have to remove the X-brace to get the pan off.
Since it's a vert, you'll have to remove the X-brace to get the pan off.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Make sure you get the filter O-ring out when you remove the filter. It tends to get stuck in the pump and the filter comes out but leaves the O-ring behind. Look at a new filter to see what the O-ring looks like.
Racer
Joined: Nov 2005
Posts: 310
Likes: 47
My mechanic and I changed the transmission filter in my 1990 automatic last month. I bought the Pro-King Filter kit (Part Number FK-171) which includes the gasket and filter from Advance Auto Parts. He liked the kit especially the gasket. I was surprised to see that it was made in China! He cleaned the pan out and took a look at the amount of filings that were trapped by the magnet. He confirmed my belief that this looked like the first servicing in my car's 65,000 life. You also need 5 quarts of ATF to replace that lost by dropping the pan. We did the work on a lift. Can't imaging doing it on blocks. There is nothing holding the filter on but the o-ring which you must replace. It appears that if the filter is not installed properly, it could drop into the pan and starve the trans of fluid.
Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
a member on here, who rebuilds transmissions for the members doesnt recommend synthetic fluid. I read his threads and what he says makes sense. doing it on blocks isnt that hard, take one end loose and let the fluid gradually drain out as you loosen the rest of the bolts...slowly. Do yourself a favor and buy a trans. pan that has a drain plug in it for a replacement. You can spend a little as $15 or as much as $300 for one. Get a steel one, if you ground your pan on a speed bump , it will bend instead of cracking and leave you stranded.
Racer
Joined: Nov 2005
Posts: 310
Likes: 47
I am not familiar with the aftermarket pans with the plugs. Sounds like a good idea though. Just make sure that it has a magnet in the pan to catch the filings. Come to think of it, maybe that is why GM did not put a drain plug in the pan as there is no way to clean the magnet without dropping the pan. Perhaps the pan with the plug has a magnetized plug to trap the filings.
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Instructor
Joined: Jul 2011
Posts: 241
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From: Tampa FL
rock auto has a nice pan for about 16 bucks, w/drain plug. Dosnt say if it made of steel. Just wondering my pan looks alittle bit rusty on the bottom. Should I replace or dont worry if I dont want to have the drain plug option?
Also as long as I dont use the synthetic oil will any dexon III fluid work that they sell at Auto zone or advanced???
Also as long as I dont use the synthetic oil will any dexon III fluid work that they sell at Auto zone or advanced???
Race Director
Joined: Apr 2003
Posts: 17,697
Likes: 1,666
From: moraga ca
With my trans pan (4l60e), I welded a booger on the inside of the pan in the front right area where there is nothing directly above. Drill a quarter inch hole and tap it. I use a drain plug with a teflon gasket. No clearance issues and makes oil changes a piece of cake. Costs next to nothing too.
Team Owner
Joined: Jul 2004
Posts: 28,352
Likes: 3,253
From: Hartford WI
I'd say that was an old wives tale told by people who have neglected the trans for eons and bring it in for service and soon after, it fails.
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
I read "somewhere" that a taxi fleet did a study on regular vs. synthetic trans oil and got double the mileage out of the transmissions with the synthetic. My recollection is that was done in Atlanta, and I believe that came from leesvet. Based on that, I just filled my freshly rebuilt trans up with Valvoline synthetic. I also put in some LubeGard, which is miracle stuff from what I've heard.
I just took the pan off my old 700r4 (110K miles -- don't know how long since last fluid change) and found virtually no metal on the magnet. There was some friction material "dust" on the bottom of the pan, though.
I just took the pan off my old 700r4 (110K miles -- don't know how long since last fluid change) and found virtually no metal on the magnet. There was some friction material "dust" on the bottom of the pan, though.
Team Owner
Joined: Jul 2004
Posts: 28,352
Likes: 3,253
From: Hartford WI
I read "somewhere" that a taxi fleet did a study on regular vs. synthetic trans oil and got double the mileage out of the transmissions with the synthetic. My recollection is that was done in Atlanta, and I believe that came from leesvet. Based on that, I just filled my freshly rebuilt trans up with Valvoline synthetic. I also put in some LubeGard, which is miracle stuff from what I've heard.
I just took the pan off my old 700r4 (110K miles -- don't know how long since last fluid change) and found virtually no metal on the magnet. There was some friction material "dust" on the bottom of the pan, though.
I just took the pan off my old 700r4 (110K miles -- don't know how long since last fluid change) and found virtually no metal on the magnet. There was some friction material "dust" on the bottom of the pan, though.
A little dust is ok. Too much is not. Metal chunks is NOT
Team Owner
Joined: Jul 2004
Posts: 28,352
Likes: 3,253
From: Hartford WI
I would really love to see some actual testing done by someone besides the seller as to whether it works or not. Preferably someone with NO Financial Axe to grind.
On a Ford Powerstroke forum, we have many that insist the larger pans that are aluminum cool better and on paper, one would think so. Unfortunately, there was a retired Ford Trans engineer that did some testing with probes all over the trans and proved that it wasn't so. The stock pan, in those applications cooled just as well as the additional capacity pans. Only difference was that you put more fluid in it and it costs more and you have the "bling factor".
On a Ford Powerstroke forum, we have many that insist the larger pans that are aluminum cool better and on paper, one would think so. Unfortunately, there was a retired Ford Trans engineer that did some testing with probes all over the trans and proved that it wasn't so. The stock pan, in those applications cooled just as well as the additional capacity pans. Only difference was that you put more fluid in it and it costs more and you have the "bling factor".
