The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 05-22-2019, 10:17 AM   #1
Jstock85
Registered User
 
Join Date: Jul 2016
Location: Brandon,MS
Posts: 489
th350 pan gasket change

Going to change the pan gasket in my trans this weekend. Got a quick question should I put on some black RTV along with the gasket to help with leaks overtime?

Thanks
Jeff
Jstock85 is offline   Reply With Quote
Old 05-22-2019, 12:22 PM   #2
Ziegelsteinfaust
Registered User
 
Join Date: Dec 2012
Location: Temple City
Posts: 3,628
Re: th350 pan gasket change

For some reason they say not too, but I have done it with out issue many times.

I prefer to get the rubber seals as they do not need anything. The cork can have a tendency to leak especially when over torqued.
Ziegelsteinfaust is offline   Reply With Quote
Old 05-22-2019, 01:42 PM   #3
Jstock85
Registered User
 
Join Date: Jul 2016
Location: Brandon,MS
Posts: 489
Re: th350 pan gasket change

Cork is what I have on there now and im going with the same rubber type. Ill put a small amount of RTV on the trans side and see how that goes.

Thanks for your help
Jstock85 is offline   Reply With Quote
Old 05-22-2019, 02:03 PM   #4
sweetk30
Registered User
 
sweetk30's Avatar
 
Join Date: May 2012
Location: horseheads,ny rust belt
Posts: 2,794
Re: th350 pan gasket change

also DRY DRY DRY before any install. or if there is atf on the surface anyplace it will most likely leak from there . and if you do want to use rtv let it cure up before you fill the trans with fluid .

i have been using RIGHT STUFF for years now and no problems .
__________________
77-k30lb BIG truck build .
87-k30lb budget beater build .
85-k30lb the plow machine build .
85-c10sb summer fun toy .
-----------------------------
HOLLEY SNIPER efi = worst case of p.i.t.a i ever had .

EDELBROCK pro flo 4 = best deal going so far . love my setup works great.
sweetk30 is offline   Reply With Quote
Old 05-22-2019, 03:23 PM   #5
demian5
Registered User
 
demian5's Avatar
 
Join Date: Aug 2016
Location: Lake Forest, CA
Posts: 2,177
Re: th350 pan gasket change

Get a one piece oil pan gasket and be done. just a little RTV at the corners at the front and rear.
__________________
"Work hard, use your vacation days."
1970 C15 GMC Long Bed
1986 C20 Scottsdale
1983 K2500 Sierra Classic Suburban 6.2
Instagram: C10sofOC
demian5 is offline   Reply With Quote
Old 05-22-2019, 05:39 PM   #6
Jstock85
Registered User
 
Join Date: Jul 2016
Location: Brandon,MS
Posts: 489
Re: th350 pan gasket change

I didn't think about letting it cure. Good advice thanks!
Jstock85 is offline   Reply With Quote
Old 05-22-2019, 07:01 PM   #7
Katrina/10
Registered User
 
Katrina/10's Avatar
 
Join Date: Oct 2010
Location: Ocean Springs, MS
Posts: 1,746
Re: th350 pan gasket change

RTV clogs valve body passages if it gets loose, that's why some say not to use it.
__________________
Gary

1971 Chevrolet C/10
1951 GMC 100
1977 GMC C15
1955 Chevrolet 3100
Katrina/10 is offline   Reply With Quote
Old 05-22-2019, 07:29 PM   #8
demian5
Registered User
 
demian5's Avatar
 
Join Date: Aug 2016
Location: Lake Forest, CA
Posts: 2,177
Re: th350 pan gasket change

Quote:
Originally Posted by demian5 View Post
Get a one piece oil pan gasket and be done. just a little RTV at the corners at the front and rear.
My bad, I was thinking engine. I had issues with sealing a th350 pan and ended up doubling up the gasket and using right stuff to seal it...
__________________
"Work hard, use your vacation days."
1970 C15 GMC Long Bed
1986 C20 Scottsdale
1983 K2500 Sierra Classic Suburban 6.2
Instagram: C10sofOC
demian5 is offline   Reply With Quote
Old 05-22-2019, 08:40 PM   #9
Jake Wade
Registered User
 
Jake Wade's Avatar
 
Join Date: Aug 2005
Location: Louisiana
Posts: 711
Re: th350 pan gasket change

Put it up clean and dry, I prefer cork. No RTV. Do not over tighten.
Jake Wade is offline   Reply With Quote
Old 05-23-2019, 10:44 AM   #10
Jstock85
Registered User
 
Join Date: Jul 2016
Location: Brandon,MS
Posts: 489
Re: th350 pan gasket change

Do you guys recommend RTV on pan side of gasket, trans side, or little on both?
Jstock85 is offline   Reply With Quote
Old 05-23-2019, 11:30 AM   #11
demian5
Registered User
 
demian5's Avatar
 
Join Date: Aug 2016
Location: Lake Forest, CA
Posts: 2,177
Re: th350 pan gasket change

It depends. If the pan is beat up, maybe glue two gaskets together and then put them on dry.

Also, while you have the trans empty, replace the oring on the dipstick tube.
__________________
"Work hard, use your vacation days."
1970 C15 GMC Long Bed
1986 C20 Scottsdale
1983 K2500 Sierra Classic Suburban 6.2
Instagram: C10sofOC
demian5 is offline   Reply With Quote
Old 05-23-2019, 11:48 AM   #12
Jstock85
Registered User
 
Join Date: Jul 2016
Location: Brandon,MS
Posts: 489
Re: th350 pan gasket change

Why the dipstick tube? Just curious
Jstock85 is offline   Reply With Quote
Old 05-23-2019, 03:48 PM   #13
Jaysonb
Registered User
 
Jaysonb's Avatar
 
Join Date: May 2009
Location: Good Thunder Mn.
Posts: 955
Re: th350 pan gasket change

Quote:
Originally Posted by Jstock85 View Post
Why the dipstick tube? Just curious
It's a common leak point, the **** shaft seal is another common area to leak. I hate fighting transmission leaks, I use lube locker gaskets, and cheap summit racing aluminum pans, and that seals things up nice, and the drain plug in the pan is a nice touch also.
Jaysonb is offline   Reply With Quote
Old 05-23-2019, 05:51 PM   #14
WorkinLonghorn
Senior Member
 
WorkinLonghorn's Avatar
 
Join Date: Dec 2006
Location: Studio City, Calif.
Posts: 2,883
Re: th350 pan gasket change

When I used to work in transmission shops we would first make sure it was the pan leaking and not something above by cleaning and drying the trans and letting it run (in gear) on the hoist for awhile. If the pan was leaking and any time we had a pan off for any reason we would put a straight edge across the pan mating surfaces and pay close attention to any gaps caused by distortion usually at the bolt holes. We would gently hammer the pans straight with a ball-peen hammer. As I recall, we never ever used any sort of sealant on any brand of trans.
__________________
'69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, stereo speakers, 2nd owner, Work-Truck supreme.
WorkinLonghorn is offline   Reply With Quote
Old 05-23-2019, 07:11 PM   #15
sweetk30
Registered User
 
sweetk30's Avatar
 
Join Date: May 2012
Location: horseheads,ny rust belt
Posts: 2,794
Re: th350 pan gasket change

if you have the o-ring seal tube clean it and the area of the case good . then rtv around it with your finger after new o-ring installed and tube is in the case bolted in place .

if you have the rubber grommet style clean dry and maybe a tiny bit of petrolium jelly on it is all thats needed . and rubber in case then slide in the tube .
__________________
77-k30lb BIG truck build .
87-k30lb budget beater build .
85-k30lb the plow machine build .
85-c10sb summer fun toy .
-----------------------------
HOLLEY SNIPER efi = worst case of p.i.t.a i ever had .

EDELBROCK pro flo 4 = best deal going so far . love my setup works great.
sweetk30 is offline   Reply With Quote
Old 05-23-2019, 10:27 PM   #16
69heavychevy
Registered User
 
69heavychevy's Avatar
 
Join Date: Jan 2007
Location: Garland,TX
Posts: 431
Re: th350 pan gasket change

I always had issues with rubber gaskets leaking. Switched to cork and never had any leaks again. Also, I don't use any RTV.
__________________
80 C10 SWB Step Side - 350 w/ vortec heads, TH350, 12-bolt 3.73
69heavychevy is offline   Reply With Quote
Old 05-24-2019, 12:56 AM   #17
franken
Registered User
 
Join Date: Jun 2013
Location: Somewhere
Posts: 3,122
Re: th350 pan gasket change

Maybe not obvious but with a sheetmetal pan/cover (1/4" bolts), I think I'd use a nut driver to tighten the bolts so as not to distort the pan, and not shear off a bolt.
franken is offline   Reply With Quote
Old 05-25-2019, 08:02 PM   #18
Pontiac1976
Registered User
 
Pontiac1976's Avatar
 
Join Date: Oct 2015
Location: Ottawa, Ontario, Canada
Posts: 766
Re: th350 pan gasket change

I have both like the cork better. Less leaks I think I just a small bead around the bolt holes on the pan side dry before you torque it down. When cork gasket time to change or ben one few yr. if the gasket start to look like getting wet it time for a change. should be changed 1yr in most cases. to keep the trans in good shape.
__________________
1977 REG cab Long Bed with a 1984 Front Clip, 82 305 .60 over 9.0.1 flat top pistons, 4bbl, TH350, w/84 SS-intake & cam , w/ 1977 big block rad, 1975 gear box, 1984 master w/ metric fittings top & SAE fitting @ portion block, 1975 3.42 gear open diff. Duel 77-87 Factory air cleaner, duel inlet from rad support . Down sized 9' to new 8' Steel flat bed
Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change.
Pontiac1976 is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 09:58 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com