I installed a 200-4R back in 2003 so I decided to drain the fluid and change the filter.
I was just wondering if anybody recommends gasket sealer or not

doesn't look like there was any used on the pan when installed from the builder I bought it from. 

Brian - NCM Lifetime Member

73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
3.55 gear BTO 200-4R trans,
Leather seats, Seatbelt Plus 3point seatbelts, Pioneer CD player
Magnaflow Exhuast System

NOOOOOOO!!!!! Clean/dry both the pan surface, and the trans pan rail, and install DRY! If the pan & trans are clean and dry, it will seal with no issues. No matter what type of gasket is used(cork, Farpac(thick treated paper) Duraprene, rubber, whatever.....they are all designed to be installed dry. The use of sealers of any kind will allow the gasket to move when you tighten the bolts, basically squishing it out of position. It also allows the trans fluid a path to escape...might not be much, but seepage is annoying too. Please always install gaskets dry. Think about it.... a gasket is not much use if you have to add some other type of sealer to it. 👍

I just rebuilt the trans in a '67 Musturd, and the guy was insistent that I not damage the $50 pan gasket he had installed, as he had been fighting a leak for a long time....and it was STILL leaking....👀

Joel Adams
C3VR Lifetime Member #56    
My Link


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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Thanks Joel

my thoughts exactly but just wanted a second opinion 

Brian - NCM Lifetime Member

73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
3.55 gear BTO 200-4R trans,
Leather seats, Seatbelt Plus 3point seatbelts, Pioneer CD player
Magnaflow Exhuast System

Joel, you mention several types of Tranny gaskets - which do you feel is the best to use on the 700-R4 transmission?

Lifetime Member #58
Our 82CE

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Do not use cork. Use a good brand of neoprene. Cork dries out quickly and will start to leak. Been there done that!

When I had leaking on my TH350, I couldn't stop it. So I went to an independant Tranny Shop, who have been rebuilding transmissions for many years. I told him of the cork & synthetic gaskets I had tried, with no success. Gill was a good friend of mine (I solo'd his son on his 16th B-day 🛩) and he told me this: Just about ALL leaks are caused by a bent Pan. As small and suttle the bend may be, it has always been the culprit for the "incurable" Transmission leak. Their shop has a way of getting the pan back to be precisely level, and then, use only the standard Fel-Pro cork gasket, DRY.

They fixed it, and now, nothing but dust down there. 

Steve

GM went to a Farpac/Duraprene gasket  on the 4L60E transmissions. They are more stable than cork gaskets, and are pretty much leak free if installed dry. They can be a major PITA to get OFF down the road....they stick to the pan and trans really well over time. I have actually re-used those types of gaskets if they are not torn, or otherwise damaged, just because it is such a freeking hassle to grind them off. 🤬

Cork gaskets will work fine, but....they have to be a quality gasket. A lot of cork pan gaskets out there now are super thin, compared to the real deal, and they are too thin to properly seal a slightly imperfect pan. 

The early style 700 pans were made of thin metal, and had strengthening ribs pressed into them...they will bend easily(especially around the bolt holes) if not installed properly. Later model 700s had thicker pans with no ribbing that work much better.(same scenario on the 350 trans pans)

Not a fan of the rubberized type gaskets....waste of money imho....once they get a little fluid on them they will swell, and squish out, far worse than cork gaskets.

Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"