RTV under pump bolts
 

As some of you may know, I have been building a 4L80 from the ground up. I have been documenting it all the way and have a little thread going which I intend to update soon with tons more pics.

The 4L80 is done, just waiting on some free time to put it in.

Upon finishing it, I torqued the pump bolts to spec with the little O-rings under them. Torquing these bolts to spec absolutely destroyed the O-rings...... I put O-rings back on a SECOND time and tried again but the same thing happened, 18 LB-Ft and the damn things are just chewed to bits.

So, I pulled the pump bolts back out and put a small dab of high temp RTV on the threads and a decent amount under the flanged head of the bolt itself. I think this will work just fine to seal it up but does anyone see a problem with doing it this way???

Do your pump bolts have a pocket for an o-ring?
Or are they regular bolts?
I often wonder if the o-rings crush enough so I sometimes add some rtv, and wipe off any excess.
Never had any o-ring tear up upon installation, let alone multiple sets.

Like Jays asked, are they the o ring type bolts? or are they the flat sealing washer type.

If you put an o ring on the flat washer type, it's going to chew it to hell. And the flat washers should really only be single time use. I never put RTV on any pump bolts, because you shouldn't need it. I don't think it would hurt anything, but I just think it looks tacky when I give a customer back their trans and it looks held together by RTV.

I wipe off the excess and you can't even tell it's there.

The pump bolts are the type with a flat flanged head built into them. But the kit came with O-rings so I used them. Between the ATRA manual and the ATSG manual I don't recall either mentioning the pump bolts being one time use. The RTV looks ok I think, just can't go crazy with and make a big mess all over the place.

Started it up for the first time and ran it for all of 5 seconds just to suck some fluid up into the valve body and pump. Course had to shut it off since the cooler fittings are open, started dripping a little bit of fluid out. Waiting on some fittings and AN line to get here in a few days to plumb into the large cooler I mounted before I try to run it again. Got plenty to do on the project in the meantime.

So far though, the RTV on the bolts seems like it will do the job, even though like y'all mentioned it's probably overkill.


I have a AutoMeter temp gauge which I brazed a fitting for into the pan. Of course it leaks so back to the drawing board on that one hahaha. You guys got any input on connecting up an aftermarket temp gauge fitting like that???? My next thing to try will be getting a fitting of that thread that is steel so I can actually weld it to the pan.

The bolts themselves aren't one time use. The sealing washers that go under the bolt head...those are one time use. Sorry if I wasn't clear.

And yes, the RTV can be wiped and look totally fine, its just not the way I like to do it. If it looks fine and is sealing, then send that thing down the road!

As others have said-NO RTV under the bolts!! If GM did not use it, I can assure you that you do not need to use it. If I were you I would be finding new bolts that have the relief cut for the rubber O-rings. I've never torn O-rings when using the correct bolts. I've also never had a pump to case retention bolt leak due to a failed O-ring. You know how you can tell a hack has been working on your transmission? When you find RTV on pump bolt O-rings, or RTV on the O/D of the pump where the large pump O-ring rides. I have units come in to the shop all the time with RTV everywhere..

When you put a Fel Pro oil pan gasket on an LS engine, do you smear RTV on the engine block, and oil pan? No? Exactly. Just not necessary. All LS engine gaskets are to be installed dry for a reason. Same with your pump bolts.

No one explicitly said no rtv under the bolts, just maybe a little dab just in case or it's ok but not necessary and could look goofy if done in a careless and shitty manner.

Just because GM did or didn't do something doesn't mean much to me. They have had a lot of really great ideas, but also a lot of bad ones. The door pin and bushing design on the 88-98 obs trucks come to mind. Another one is their decision to use a dropbase air cleaner on the 80s and 90s cars and trucks and then tossing on the little choke collar underneath it to space the air cleaner back up so it wouldn't hit the coil. The reasons for this are probably varied, trying to cut assembly costs... Or perhaps the inevitable oversight of a bunch of engineer and MBA types with extensive theoretical "knowledge" but little to no real world experience.

I have two 4L80s here, both having the same type of pump bolts. I used the Orings that were for the pump but they didn't cut it so I decided to use RTV instead of dicking around with finding the "correct" pump bolt o rings again. The trans has been in for a couple days now and the RTV is working great and you cant tell it's even there.

Sure, the LS gaskets are all supposed to be "dry". But after taking my water pump off a half dozen times to meticulously clean and prep the gasket matting surfaces to try to stop a leak I finally decided to "break the rules" and use some high tack sealant along with the gaskets. It stopped my leak. I'm not the only one to have done this and while it may technically not be the "correct" way I couldn't care less simply because it solved the problem. Maybe with a bunch more aggravation I could have figured out a way to dry install the gaskets like they were intended and not have a leak. I'd rather hammer that shit together and move on so that's what I did hahaha.

I'm either a grade A hack, or just a jack of all trades because I can do anything with what I have available and figure out a way to make it work one way or another. PCM tuning, wiring, automatics, manuals, transfer cases, differentials, engines, paint and body, home made turbo system fabrication, fuel injector decapping and flow testing. I'm a jack of all hacks hahaha.

First off, if you're under my car looking at the pump bolts you're going to be dealt with before you have a chance to assess the rtv problem. No one works on my car except me.
Second, you can't tell its even there.
What do you do thats not "by the book?" Theres something, theres always something. I bet it's worse than rtv hidden under a pump bolt.

By the book :drool: I see none of your engine swaps have ever started right up without some issues. Hacks usually have issues. You never update the thread and say what was wrong.

Probably not much of anything one way or another. The guy seems like a google warrior after a quick review of his posts.

Rumor has it he's still trying to figure it out to this day.










By the way! The HACKS at ATRA even use RTV/silicone!!!!!!!!!!!!!!

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So, the things to take from this thread.
1-rtv under the pump bolts is fine. Its not my preferred way, but it works and doesnt hurt anything, so I'm not going to tell anybody that they shouldn't do it
2-kawa whoever needs one or two chill pills
3-calling people hacks is probably not going to have any positive results.:engarde:

Oh, and just as a fun little side note to kawa...yes, you do use a little dab of RTV each and every time you change an oil pan gasket on an LS. so did the factory...where the pan meets up with the timing cover and rear oil seal cover...you need a touch of rtv:cheers:
https://cimg2.ibsrv.net/gimg/ls1tech...60b5262eb6.jpg
https://cimg5.ibsrv.net/gimg/ls1tech...46bfa1a5e3.jpg