Lmtv oil pan r&r

[sjohn116]

Has anyone changed the oil pan gasket on the 3116 in your lmtv? TM states that you have to remove the transmission cooler, but it looks like you might be able to slide the pan out without removing the trans cooler. Can anyone advise if this is indeed the case? Thanks in advance.

 

[Smike740]

I replaced mine. I removed the cooler lines and cooler since I was also replacing the front housing. You may get by with just removing the lines, if there is enough clearance to drop the pan at the rear to pull it out

 

[tennmogger]

Edit, we posted together, you can certainly do it Smike740's way too, but here's how i did it:

The trans cooler does not have to come off, that is, you do not have to disconnect trans fluid piping and drain the transmission fluid. But, you do have to drain the radiator if done this way. Disconnect the engine coolant hoses from the trans cooler (in front of oil pan) and drop it down out of the way of the pan just a little. You can separate the coolant lines just enough to lower the pan from between them. The trans cooler heat exchanger needs to be supported at all times. I used small ratchet straps from the frame on each side, which facilitated separating the coolant lines "just enough".

Big hint: the two brackets holding the heat exchanger are slotted on the top bolt. You don't have to remove the bolts.

I have had continuing problems with two bolts loosening from the pan, and oil escaping just enough to make a mess. The pan had been re-sealed before I got it too, most likely in the military. They did a poor job, probably by not taking out the pan and cleaning the surfaces. They just glopped on a bunch of sealant and screwed it back together.

I suggest you take every step you can to ensure a good seal the first time because this is a nasty job. The engine will be dripping black oil in your face the whole time. I took off the pan, let engine drain overnight, then still got nasty the next day.

What could cause two bolts to always back out? Threads were cleaned in block (brake cleaner) and on the bolts, Blue Locktite applied liberally, left 24 hours to set up, and still the bolts backed out. Last attempt to fix this was to replace the two bolts with threaded rod, lock in with Locktite, put on one set of nuts and washers, add a 'keeper' plate made from a metal strap drilled for bolt spacing, then a locking nut on each rod. They sure won't back out from that!! fingers crossed.

Maybe this rambling helps.

Bob

 

[tennmogger]

When I replaced the two oil pan bolts with studs (threaded rod) and used a locking bar and second set of nuts, I thought that would be the last of it. Well, the leak was back. Today I took off the two locking nuts (still tight) and locking bar and the two primary nuts against the oil pan were loose again. I do not know how that was possible.

How can two 'Locked' nuts get slack under them? The studs were still tight in the block. The only reason I can think of is that the thickness of the thin gasket was reduced even more. This is a standard CAT gasket for this 3116. Has anyone heard of a cronic problem with earlier oil pan gaskets???

Perhaps securing the pan with Belleville washers might work?

thanks.

(shortened post) What could cause two bolts to always back out? Threads were cleaned in block (brake cleaner) and on the bolts, Blue Locktite applied liberally, left 24 hours to set up, and still the bolts backed out. Last attempt to fix this was to replace the two bolts with threaded rod, lock in with Locktite, put on one set of nuts and washers, add a 'keeper' plate made from a metal strap drilled for bolt spacing, then a locking nut on each rod. They sure won't back out from that!! fingers crossed.

Bob

 

[Floridianson]

I am doing my 1997 3116 Kitty M1088 now. They gave me the thin paper one but it leaked. Went back to Cat and asked for this one. I have steel cooler lines so yes I had to remove cooler and it's bracket from the motor. Yes I loose some fluid. After it drains I just put a plastic bag and tape it closed on both Hyd. lines. I tied very carefully the steel lines to the side on the exhaust pipe because that is a far as it will go. The other line just to the side a bit so pan will clear. I will also use thread sealer on all bolts but gasket goes in dry.

 

[coachgeo]

Is that Viton Rubber Gasket?

 

[Floridianson]

Is that Viton Rubber Gasket?

I don't know but that is what was on there when I took the pan off the first time.
I say it is easer to remove cooler and it's bracket. If you have steel lines just watch very carefully for the small O ring on the end of the lines. They can be used again if you don't hurt them. I used four stud pilot bolts and in six places around the oil pan tie the gasket on the pan with fine thread from your better half. After the pan has six bolts in it just reach up with a pair of plyers and rip out the thread. The cool thing is the thread never touches the sealing rubber gasket as the holes are on the outside of the gasket.

 

[Waters]

Any luck with these gasket fixes? I have a nasty leak from mine when the oil gets good and hot.
Its the rubber/plastic type currently, i called my local CAT and gave them my engine serial and they said that this calls for RTV instead of a gasket now.

oh, mine is a 3126. The only gasket i can find online is aftermarket, and i cant locate a CAT pn for the 3126. Would it be the same as the 3116?

i have used RTV as an oilpan gasket for years on my old slow 6.5td, but this job would be so much easier and cleaner with a real gasket. I could probably not even remove the trans cooler as i have flexible lines. Just slide the pan out and then back in with new gasket.

 

[Floridianson]

Mine doing fine but it was a # 6 in the pain of the butt scale when done alone.

 

[tennmogger]

I learned the hard way that gaskets won't stay sealed. Three times, three gaskets failed. The vibration of the engine causes movement along the gasket. Use Permatex Right Stuff gasket maker and no gasket. Mine has held for several years now. Hope the pan never has to come off.

Installing metric threaded rod in place of a couple of bolts on the ends of the pan will greatly simplify getting the heavy pan on straight.

 

[Floridianson]

Yea the threaded rod or cut off bolts heads for aliment of the pan make it easer. I also did the same thing for the oil cooler when I did those gaskets. Glad I was in better shape when I did the pan by myself. One hand did the bolts and one foot to hold the pan up till I got a couple of bolts started. Now I grunt when putting on my socks in the morning so I am glad that is done and truck sold.

 

[MrMikey4026]

Pan gasket
I just replaced my 3116 pan gasket. It looks easy, but not so much, it took me most of the day.
It appears to me that the oil slinging off the oil pump gears splash right on the right side of the pan, pushing oil between the pan and the gasket.
I was able to remove the lower bolts from the oil cooler and swing the cooler forward, the pan will not clear the oil pump with the cooler bracket installed in the normal position. My truck has a soft cooler line update installed, so I did not remove the hoses. Getting the cooler bracket bolts back in can be interesting.
The bolts are also the front motor mount bolts, they shifted just enough that the bolts would not line up. I had to jack up the front of the engine to correct that problem.
Someone had been in there before and installed the gasket upside down, I used the cardboard gasket from Cat $44. It is marked "block side", although I really don't see any difference in the gasket?
I coated both sides of the gasket with Loctite 515 anaerobic sealer, torqued the bolts to 270 in lbs.
It has run for several hours, no leaks.
Time will tell.

 

[Waters]

Just finished doing mine on the 3126.

i dont have whole days ever so it was a bit of multiple days.

i had the driveshafts out for a balance too so i had better access. And the truck needed an oil change so it got done at the same time.

my problem area was in the back where the bellhousing makes up the mating surface for the rear of the pan. There is less width here than on the sides, and thats where my plastic/rubber/metal gasket was leaking.

have yet to fire it up and see how it does but i expect it will be fine.

i did buy m8x1.25 studs to help raise the pan with rtv on it and not smear it off on the transmission cooler lines. Just cranked 4 nuts until the pan was evenly mated and started putting in bolts.
The TM has you do 4 corners to spec and then go ccw doing the 32 others (23 ft lbs). That seemed like a good way to do it so i followed along.

Worst part was the top bolt on the trans cooler bracket, driver’s side. There isnt room to fit a socket, Just enough room to move a wrench 1/4” at a time and who has a ratcheting 22mm wrench?

ended up having to alternate 22mm and 7/8 wrench just to get the 12 point box end to grab each time.

 

[TomTime]

Just finished doing mine on the 3126.

i dont have whole days ever so it was a bit of multiple days.

i had the driveshafts out for a balance too so i had better access. And the truck needed an oil change so it got done at the same time.

my problem area was in the back where the bellhousing makes up the mating surface for the rear of the pan. There is less width here than on the sides, and thats where my plastic/rubber/metal gasket was leaking.

have yet to fire it up and see how it does but i expect it will be fine.

i did buy m8x1.25 studs to help raise the pan with rtv on it and not smear it off on the transmission cooler lines. Just cranked 4 nuts until the pan was evenly mated and started putting in bolts.
The TM has you do 4 corners to spec and then go ccw doing the 32 others (23 ft lbs). That seemed like a good way to do it so i followed along.

Worst part was the top bolt on the trans cooler bracket, driver’s side. There isnt room to fit a socket, Just enough room to move a wrench 1/4” at a time and who has a ratcheting 22mm wrench?

ended up having to alternate 22mm and 7/8 wrench just to get the 12 point box end to grab each time.

I bookmarked your post just in case I needed to drop the pan on my engine in the future, and now I do. Your post is the only one I could find that addresses the pan removal on a 3126 Cat engine. I've seen several post and videos about the 3116 engine but there is enough of a difference between that and the 3126 that makes it more difficult.

I have a 2002 M1083A1 with a 3126 Cat. I've removed the trans cooler and now I need to remove the trans cooler bracket, which looks like it will be a PITA. The bracket has to be removed to be able to drop the pan down low enough to clear the oil pump. With the bracket in place there is not enough clearance.

The passenger side bolts on the bracket look like they'll won't be to bad getting out, but the drivers side upper or top bolt looks almost impossible to get out without removing the air compressor. You said that you use a 22m and 7/8 inch wrench on the drivers side top bolt. It doesn't look like there isn't enough room to back the bolt out to clear the air compressor. There isn't enough room on the drivers side of the bracket to move the bracket forward by just removing the lower bolts and loosening the upper bolts.

Were you able to get the drivers side top bolt completely out?

Also, If anyone else has removed the oil pan from a 3126 in a FMTV and has any tips on getting the oil pan down please let me know, I'm right
in the middle of this repair.

Thanks.

Tom.

Trans cooler.



Trans cooler removed.



Trans cooler bracket drivers side bolts. No room to loosen bolts and move forward.





Trans cooler bracket passenger side bolt.

 

[Waters]

I bookmarked your post just in case I needed to drop the pan on my engine in the future, and now I do. Your post is the only one I could find that addresses the pan removal on a 3126 Cat engine. I've seen several post and videos about the 3116 engine but there is enough of a difference between that and the 3126 that makes it more difficult.

I have a 2002 M1083A1 with a 3126 Cat. I've removed the trans cooler and now I need to remove the trans cooler bracket, which looks like it will be a PITA. The bracket has to be removed to be able to drop the pan down low enough to clear the oil pump. With the bracket in place there is not enough clearance.

The passenger side bolts on the bracket look like they'll won't be to bad getting out, but the drivers side upper or top bolt looks almost impossible to get out without removing the air compressor. You said that you use a 22m and 7/8 inch wrench on the drivers side top bolt. It doesn't look like there isn't enough room to back the bolt out to clear the air compressor. There isn't enough room on the drivers side of the bracket to move the bracket forward by just removing the lower bolts and loosening the upper bolts.

Were you able to get the drivers side top bolt completely out?

Also, If anyone else has removed the oil pan from a 3126 in a FMTV and has any tips on getting the oil pan down please let me know, I'm right
in the middle of this repair.

Thanks.

Tom.

Trans cooler.
View attachment 875567


Trans cooler removed.
View attachment 875568


Trans cooler bracket drivers side bolts. No room to loosen bolts and move forward.
View attachment 875573

View attachment 875569


Trans cooler bracket passenger side bolt.
View attachment 875570

Man im glad i wrote that out cause i completely forgot how id done the driver’s side.
You just have to loosen the pass and driver top bolts enough to slide the bracket down, with the bottom bolt completely removed. Top hole is slotted straight upward.

i had to use the 7/8 wrench with the correct 22mm wrench just in order to give me a slight variation inwrench handle to 12point sides orientation, since the wrench can barely swing. Id turn one a few mms, put the other wrench on and turn it a few mms.
Like i said a ratcheting 22m wrench would do wonders. Just dont run the bolt way out and get stuck….

 

[TomTime]

Yeah I know what you mean about writing things up. The older I get the more I have to document what I do and that’s why I take a boat load of photographs when doing something.

The top of the bracket is slotted, that’s GREAT, you can’t see that while the bracket is in place.

Thank goodness I purchased a lot of tools in my younger years even though I didn’t need them at that time. I have a complete set of GearWrench ratcheting wrenches and one is a 22mm. With that said, not sure it will fit up in that tight area where the drivers side top bolt is. The ratcheting head might be to big, we’ll see. Of course I have other wrenches in case it doesn’t work. I’ll let you know how that goes.
Thanks for the reply!!!
Tom.

EDIT: I just hope I can break the bolt loose without rounding off the head of the bolt with a 12 point wrench.

 

[chucky]

Just a little food for thought ! I thought my pan gasket was leaking and was going to replace pan gasket but just happend to find the leak coming from the oil cooler on the passenger side of the block just above the pan ! I gunked the hole motor real good and got it clean then cranked it up and started watching and sure enough oil cooler !

 

[TomTime]

Just a little food for thought ! I thought my pan gasket was leaking and was going to replace pan gasket but just happend to find the leak coming from the oil cooler on the passenger side of the block just above the pan ! I gunked the hole motor real good and got it clean then cranked it up and started watching and sure enough oil cooler !

Not really leaking. No leaks at the oil cooler. Dropping pan for several reasons. One, the truck sat for a long time and the injectors froze up and rust developed on the rocker arms and most likely inside the complete engine. Two, drained the oil for a second time, with only 1.5 hours of run time on the new oil and the oil was black, again. Three, and the main reason, bent two pushrods on number one cylinder only after 1.5 hours of engine run time since the new injectors were installed. Dropping the pan to see if there is any metal in the pan and to check for any interior damage. Fingers crossed.
(Already removed, cleaned, reinstalled rocker arms/shaft and replaced push rods. Lifters move freely. Removed the #1 injector, scoped the cylinder/piston, and reinstalled replacement injector under warrant). Hopefully it's not the cam...fingers still crossed.

 

[TomTime]

Well, I was able to get the trans cooler bracket off after about 30 minutes of working on it.
Actually the drivers side bolts were easier to break loose and the passenger side bolts were really torqued on. Finally broke them loose with a breaker bar and a cheater pipe on the end of the breaker bar.
The ratcheting wrench barely fit in the space on that top drivers side bracket bolt. I was able to use it to break the bolt loose. I then used a 7/8 inch wrench in conjunction with the ratcheting wrench, sparingly. Unfortunately my 7/8 inch wrench and my 22mm wrench 12 points matched up exactly when overlayed them so only one was helpful.
So after that I was able to drop the trans cooler bracket down and off. After taking off a couple of coolant line brackets off by the front of the pan and the CTIS air lines on the front axle I was able unbolt, drop the pan and slink it out and around the front axle, and out under the radiator. The TM (for the 3116) and info online say the pan bolt are to be torqued to 21-25 ft lbs. When removing the pan bolts they were definitely torqued way more the 25 ft lbs.
The pan gasket was the rigid metal/plastic and rubber one and appeared to be original. The replacement I got from Cat was the same type, 166-2905. The old gasket had no sealant or RTV on it that I could see.
The good news, NO metal pieces, parts or anything else was in the pan except for a little sludge. There was no lower end damage that I could find even with the endoscope.
I did find the the oil pickup tube screen was about 35-40% clogged with some debris though.
Completely cleaned the pan, bolts and underside of the engine, pickup tube screen, installed the new gasket, and reinstalled the pan.
I did used a trick that @Floridianson mentioned in his 2016 post, about using sewing thread to hold the gasket in place stud bolts to help line up the pan, thanks @Floridianson.
Now to reinstall everything that was taken off to remove the pan.

So back to pan bolt torque. As I said the TM and other info said to torque them to 21-25 ft lbs. If I remember correctly there was a post here or somewhere, where they stated they torqued them to 270 ft lbs. Again, when removing the pan bolts, they were torqued more then 25 ft lbs.

Is the correct torque for the pan bolts 21-25 ft lbs? I would like to get the torque correct before adding the oil back in! I'm I missing something here?

 

[Lostchain]

I changed my oil pump this weekend on a 3126B . Not much to add other than the top drivers side bolt of the oil cooler mount required 2 different 7/8 12 point wrenches to be able to make the bolt rotate in the tiny space available. A ratcheting wrench wouldn’t fit.

Also, I zip tied the tranny cooler lines to the frame rails and removed the exhaust down pipe to get great access to the pan from the back. Made installing the pan uneventful.