'97 K2500 Suburban L29 454 ---Replacing Rear Engine Seal and Oil Pan Gasket

[RedBurb]

Hello, Newbie to the site.

I bought the '97 a few months ago with 179K miles on the odometer. The primary use will be occasional towing of classic cars to & fro shops and shows. Expect to put no more than 2-3K miles on it per year. Everything on the drive train seems to works flawlessly and sounds solid.

However the engine's pan and frame cross-members were covered with nasty oil gunk when I bought it. Contrary to some opinions oil gunk is NOT a rust inhibitor plus I quickly got tired of oil dripping on the driveway. So I jumped on the repair last week. The rear seal and the oil pan gasket under the rear main were the worn culprits. I decided against pulling/lifting the engine out so instead removed the major components required to access the seal and oil pan gasket. Now finally, but decidedly not innocently laying on ground are two tires, the exhaust pipes and collector, drive line, the transmission cross member, transfer case, starter, transmission inspection cover, transmission, flex-plate, steering rack, front differential, cut cardboard, grease snots, and hellish smears of various lubricants all over that holy driveway. Also dangling are tagged and labeled spider webs choke full of wires and connectors. Yep, fun job.


I believe in tapping into the wisdom of others so my question to those of you who may have tackled such a job before is do you have any suggestions or recommendations on what other parts I "might as well" replace and/or inspect now that almost everything other than the engine is on the ground?

Appreciate any thoughts on the matter.

 

[Schurkey]

Fuel filter?
Trans flush and filter?
Transfer case fluid drain 'n' fill?
Suspension overhaul?
Brake overhaul?
Change front (and rear) diff fluid?
02 sensors?
Verify U-joints.
Flush brake fluid.

 

[Carlaisle]

I'm only being slightly facetious when I say I would probably replace all of the bearings while I was in that deep and check the compression on each cylinder and consider replacing the rings on any that are too low for comfort.

 

[GoToGuy]

Wow, just wow. For a rear main and oil pan, finally an OCD just me.

 

[RedBurb]

Fuel filter?
Trans flush and filter?
Transfer case fluid drain 'n' fill?
Suspension overhaul?
Brake overhaul?
Change front (and rear) diff fluid?
02 sensors?
Verify U-joints.
Flush brake fluid.

Good list thank you. I'll replace all fluids for sure and the tranny filter. The suspension, brakes, U joints etc. look and feel fine. I've thought about the O2 sensors (total of three I believe) but will probably roll the dice on these since accessing them at a later point seems fairly straight forward. However I'm considering changing out the input/output shaft seals on the tranny and transfer case(s).

 

[RedBurb]

I'm only being slightly facetious when I say I would probably replace all of the bearings while I was in that deep and check the compression on each cylinder and consider replacing the rings on any that are too low for comfort.

Happy note of relief to self : "Darn! If only I had checked compressions before tearing everything apart. Oh well, too late now, next time..." I sure hope this duck and dismiss doesn't bite me soon. But thanks for the suggestion.

 

[RedBurb]

Wow, just wow. For a rear main and oil pan, finally an OCD just me.

It's comforting to know I'm must be amongst friends. Yep, still thinking about that darn compression,,,!

 

[yevgenievich]

I went to change the starter on my elco, that went to oil pan and rear main seal, and that followed to all the bearings being changed, timing cover, front seal, intake gaskets and valve seals.
If transmission is down, would closely inspect and do a refresh if there is decent material in the pan from clutches.

And then while you have front diff out, might be worth replacing all seals on it and bushings.

I usually at least replace front seal on the transmission if trans is out

 

[L29Sub]

You indicate the engine ran well, doesn't smoke, cranks OK. If so, and the oil pressure guage was above zero hot idle, I'd leave the engine bearings alone. If the bearings are that worn, so are the pistons, rings, wrist pins, lifters, cam, drive chain, ad infinitum. If it wasn't knocking on startup, you're good to run for a while. If it was knocking on start or hot idle, pull the engine.
Add to this, getting a good clean fit while working under that truck is going to be a challenge.
Those engines will begin to smoke long before the rotating mass fails....assuming reasonable past maintenance.
Not worth going into and creates more failure points. Not enough access for clean inframe.
The oil pan and rear main seal will leak if the engine has crankcase pressure related to worn engine or PCV system faults. All crankcase vent plumbing and seals must be in serviceable condition for correct function.
Check the back of the intake manifold base for blown out sealant near the distributor for wet oil. BB 454 is famous for that blown out sealer and it'll create a nice oil leak and look like a rear main seal failure.
Be very careful with plastic connectors and brittle wiring.
IMHO and YMMV.


Sent from my SM-G965U using Tapatalk

 

[HotWheelsBurban]

Not sure about the big block, but on my 99 5.7 Burb, the 2 rear oxygen sensors are easy to do. I have to jack the side of the truck up a little bit because of the running boards, but mine is also 2wd.
The ones on the back of the engine are a lot harder, unless you have a lift to put the truck on. Then you can get the correct angle to get leverage on it to break it loose. And even on the small block, there's not a lot of room to work.
If you have access to a lift to work on the Burb, though, you're way ahead!