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Rear main seal

Drey

Drey

3/4 ton status
Joined
May 8, 2003
Posts
8,286
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16
Location
Iowa
Mine leaks like a sive. What is all involved with putting in a new one, and can it be done with hand tools, 4 jack stands and a standard floorjack. /forums/images/graemlins/1zhelp.gif
 
You need a torque wrench for the main bearing cap bolts! Al ong piece of wire and drop the pan and trans inspection cover! Don't need to drop the transmission! /forums/images/graemlins/thumb.gif
 
so i take it ill have to refill my 700R4 too, check, im sure my dad has a torque wrench. Do i need to pull the flywheel too? Im sorry if these are really obvious but truth be told, Ive never torn much appart mechanically.
Sparkplugs, GlowPlugs, Fuelfilters, Brakes, and pulling a TCase is all ive done mechanically.
 
NOPe, You're not droping the 700, just removing the dust cover for the flexplate! You don't have to undu the flexplate either! Once you get the oilpan off, you'll see what I'm talking about! You gain nothing in space by removing the transmission! The crank mushrooms out right after the rear bearing cap, therefore you still are imited by that in space to work by, removing anything other than this in this order is unnecessary:
1) Dust cover for flexplate, 8 bolts
2) Starter 2, or 3 bolts if include small one on engine mount
3) Oil pan, ALOT OF BOLTS! Maybe Oil pump bolt too, pending on amount of lift!
4) Rear Main cap, 4 bolts
5) Whatever is left of your old rear main seal(MINE HAD NOTHING IN THERE!)

Reasemble backwards using correct torque specs! /forums/images/graemlins/thumb.gif
 
Oh, Also, buy about 2 rear main seals and you can forget the pan gasket! Use RTV! Tighten down the front bolts on te forward lip pretty snug before tigthening down the sides or back! If you don't use RTV,it's a Pain to seal! Also, if you don't tightne the front lip first, it won't ever seal!!!!!!

The reason you want two rear main seals is that it gives you 3 trys to get the new top one in correctly(IT'S NOT EASY, take time and clean real well!) and the seals are cheap! The bottom half is simple!!!!! THat's what the last piece is for! /forums/images/graemlins/thumb.gif
 
Thanks a bunch man. /forums/images/graemlins/thumb.gif Hopefully Ill tackle this soon and get the beast to stop leaking. I have no lift, so im hoping my pan will clear the axle, if not ill jack it up at the frame to unspring the front leaves.
Thanks again, i owe you big time
 
Good advice, but you forgot a biggie...you have to unbolt the engine from the mounts and raise the engine about 3 inches so that the oil pan will clear the crossmember. Its not fun. I just did mine about a month ago.
 
[ QUOTE ]
Good advice, but you forgot a biggie...you have to unbolt the engine from the mounts and raise the engine about 3 inches so that the oil pan will clear the crossmember. Its not fun. I just did mine about a month ago.

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Exactly. /forums/images/graemlins/thumb.gif
 
I hate to disagree, but I just did mine 3 months ago and I never unbolted my engine!!! The engine cleared the crossmember just fine!!!!I did have to raise the front end off the ground to be able to clear the oil pan on the front axle, but that is all!!! Sorry, but no other problems here! /forums/images/graemlins/thumb.gif
 
to clarify some stuff, its a 1983 GMC 4x4 Pickup. Maybe that will determine if my crossmember is in the way or not.
 
I also left my engine in place, its probably a 4wd thing. 2wd may need engine jacked up
 
Mine is an 85 4wd K20 /forums/images/graemlins/burb.gif. There wasn't even close to enough clearance to get the oil pan off. Maybe you don't if you have a gasser, but with my 6.2, I had to raise it.
 
2wd definitely needs it, my guess is that 4wd shouldn't since the cross member is further to the front.
And since most of the 4x4 guys already proved it, I wonder if there was anything different with the truck that still needed the engine raised even though a 4x4.
Did it have 2wd engine mounts?
Did it have anything different from OEM?
Is it because it's a K5 maybe the trucks had it different?
 
My /forums/images/graemlins/burb.gif is a 4x4 and I had to raise the engine. there was no way the pan was going to come out with it in the cradle. Maybe its because it's a 3/4 ton. I do know that the 2wd and 4wd frame-side engine mounts are different. I also had to remove 2 struts that tie the engine mounts and the flywheel cover together.
 
Yes you do have to remove the "support bars" but that might be it!!! Nobody in here is going to be talking about doing a rear main on a "gasser"!!! /forums/images/graemlins/rolleyes.gif

It is tight, but by no means do you have to remove the engine!!!! Just jack up the truck from the frame to get the oil pan to drop far enough (Axle out of way)and it slides right out!! /forums/images/graemlins/thumb.gif All 6.2 Diesel 4x4 trucks,(K5 and K10,K20,K30) have the same front crossmember towards the front! THERE IS NO REASON TO RAISE THE ENGINE! Just lower the axle! It's that easy! /forums/images/graemlins/deal.gif
 
now is this with a lift kit or without cause i have no lift and am thinking about doing this also.i might leak a quart a month so its not a river but it still needs to be done.so post up! /forums/images/graemlins/deal.gif
 
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now is this with a lift kit or without cause i have no lift and am thinking about doing this also.i might leak a quart a month so its not a river but it still needs to be done.so post up! /forums/images/graemlins/deal.gif

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you suck man, i drove my truck 30 miles and back came home, im 3/4 quart low /forums/images/graemlins/angryfire.gif
 
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