KMAPRO

Just to catch anyone up who hasn't seen my other posts referencing my 87 MJ... 4.0 - 5 spd. 4x4..Replacing rear main seal because I have renamed the truck Exxon Valdez. Had to pull the engine to change the rear main seal because the oil pan was stuck to the bottom of the block. I pulled the engine, transmission and t-case all at once. I finally got the oil pan off by taking a 5-in-1 and gently working it around and around the oil pan. Then took a 3/4" wide chisel and gently worked the remaining gasket off - took about an hour and a half. I have also removed the rear main beaing cap. Here is why I am asking if the block is fubarred...I was checking everything out and planning the procedure for removing the upper rear main seal when I noticed that the little steel lip, between the seal and the back of the block, has the corner broken off. Since I have announced, in the past, that I am not a mechanic and just learing as I go, is this part of the upper bearing or is this part of the block? I am assuming - and hoping - it is part of the bearing. Is this critical? Should I replace the upper bearing or will it be OK? It only looks to be the corner of the keeper.

Thanks y'all. Wannabe - That was one of the threads I did find when I did my search prior to posting. As a matter of fact, it was the very first one I read when I did my search. After doing some more research, the group seems to be a bit divided and I would like to know what everyone's real opinion is about pulling everything or undoing the t-case before I pull the engine and tranny out. For the record, I do not have a load leveler. Everything that goes in front of the engine is either removed or moved out of the way, so it is a clear shot. And on another note, sorry I forgot who posted it but, someone mentioned just removing the tranny crossmember and lowering the back side of the engine down far enough to get to the bolts on top of the bell housing. this also seemed fairly simple...My concern here is putting it back together. For the record, I recently pulled and replaced the engine on my 01 Dodge Ram, so this is not my first rodeo...it's just the first time on an MJ and it seems a bit more difficult than the Ram.

OK, did some more searching and saw where some of y'all say it is easier to remove the transfer case from the transmission before pulling it. Which 6 bolts do I need to remove in order to do this?

OK, I did a search before I posted this but I am sure that there is a post on it somewhere and I was just looking up the wrong keywords... 87 MJ - 4.0 - 5spd 4x4 I was originally just going to pull the engine and not worry with everything else, but the two bolts at the top are just a wee it hard to get to with my limited mechanical abilities and knowledge...So, after reading a few posts on here, I decided to just pull the whole thing. Before I get in to what I have done, let me tell you why I am doing this. I have to replace the rear main seal and yes, I know I don't have to pull the engine to do this but the oil pan is seized/stuck to the bottom of the block and will NOT break loose for anything. I also have to replace the motor mounts as the ones I have are totally gone - so I figured why not just pull it - fix it - clean it up - apply a fresh coat of paint and put it back in. Before it goes back in, I will also be replacing the valve seals as well - try to fix my spark plug foul problem. OK, as mentioned, I was going to just pull the engine, so I already have the motor mounts undone - wiring harness removed and all other plumbing under the hood undone. Now, I need to know everything I need to do for the rest of the job. Also as mentioned, I am not a mechanic but I aint afraid to try it either. I am assuming that the rear yoke will just pull out of the tail shaft on the t-case when the engine is pulled. Are there any hoses that I should not undo from the tranny? As in, coolant hoses or anything? What about linkages? OK, in simple terms, please explain everything that needs to be done from the back of the engine to the rear driveshaft please. I know that is asking a lot, but I am frustrated as all get out with this thing right now and need some help. Thanks for any/all help/advice.

Everything still seems good and flexible on my end. The only exception is the wire loom surrounding the wires in places. It just crumbles in my hands when I pull it out. Thanks for the advice and I will make double sure I get all the pan bolts!!!

OK - I am glad I listened to y'all. Did a compression check this weekend and compression was good across the board. Looks like I will be replacing the seals..... I will still need to pull the engine because I have to replace the motor mounts and do the rear main seal. I know I could do the seal with the engine in the truck, but the oil pan is stuck and I have not been able to get it off. I have tried everything that has been suggested in other postings I have made on the subject - still no luck. While it is out, I plan on painting the engine bay and the engine as well. I will start posting pis of the build as I go along in the proper forum.

Thanks Harper - I will do that first then. As a side note, I did talk with my father concerning the problem over the weekend. He said that some of his workers drove the truck and ran it hot. It could very well be something in the head or the valve seals. I will check the seals first and then decide which course to take.

http://www.comancheclub.com/forums/viewtopic.php?f=2&t=24008 I knew that there was just a trick to it...Thank you

Thanks guys. I just misunderstood the explanation the fist time around. Makes sense now.

Thanks Geneovast for the info. If this turns out to be the problem - will it hurt if I make the truck full time 4wd? I am assuming that this is what it would do. Remember, I am using this truck as an EVERY DAY driver. Will I experience excessive wear and tear?

OK here is more info... Truck info: 1987 model 4.0L I6 5 spd manual transmission - I believe it to be the crappy Puegot BA10/5 (I think that is the right info) Transfer Case - I believe it to be the NP-207 because the information I have read says that the 207 was used until 87 and then the 231 replaced it. I don't know if "until" included 87 or not. I don't know how to tell. Front Axle - Dana 30 Rear Axle - Dana 44 I believe this to be a "Metric Ton" package due to the fact that it has the D44 rear end and it is a long bed. What I have already done: I was experiencing oil blow-by as someone mentioned. I have already upgraded to a newer valve cover. I am running a valve cover from a 96 model and the felpro gasket. Other than patching some holes in the floorboard, that is all I have done. Why I am doing this: The valve cover swap helped with the blow-by, but did not eliminate it. I also keep fouling spark plugs at the #2 cylinder (like every other day before I installed a no-foul adapter). For these two reasons, I believe the rings to be bad on the #2 piston. I also have a very bad oil leak coming from the rear of the engine - rear main seal. I am literally going through 5 quarts a week. I am not burning it - I am leaking it..or it is marking it's territory. The engine has a little over 150k miles on it. I figure the cylinder needs a good honing while I have the piston out for ring replacement. If I am doing one of them, I might as well do them all. Since I will also have the oil pan off to replace the rear main seal and the pistons out, I might as well go ahead and replace the bearings while I am at it. When I am at a red light - truck out of gear and foot off the clutch - I hear a slight knock or bump coming from the transmission. If I push in the clutch, the sound goes away. I can only assume this to be the throw out bearing/slave cylinder. Any body got any other ideas as to what this could be? I know 4 wheel drive is not working because I was recently doing some yard work and had to hook to a small stump to pull it up. I shifted into 4 wheel drive, tightened the chain and all I did was spin - rear tires only. The truck is running street tires (hand me down from my father who used the truck as a company truck until he sold his business), so it doesn't take much for it to spin on wet grass under load. Now it does shift down in to the lower gear range, but I get no pull from the front end at all. I do not get any pull from 4 wheel Hi either. I know that the 4 wheel drive system worked when I got the truck, because I used it for similar projects around the yard and never had a problem. I have always had 4 wheel drive trucks, but have never had to work on them because I never had a problem with them. So, I can only assume it is the transfer case. Sorry, but I have no idea what the CAD is... If someone could tell me how to check the transfer case out, I would appreciate it. Now that you know the full story, does it sound justifiable to be doing what I plan on doing? I am open to other suggestions. My goal is to have the truck back on the road within 2 weeks. I am only working on it at nights and on the weekends - and when funds allow. My 01 Ram 1500 uses too much gas to be driving every day - which is why I have the MJ any how.

OK Y'all - It has been a while since I posted on here and I apologize for that but I have been extremely busy with work lately. I am finally getting around to pulling the engine on my 87 MJ (4.0 - 5spd). I am tired of getting better gas mileage than oil mileage. My plans right now (engine wise) are to replace the rear main seal, hone the cylinders, install new piston rings and new bearings. While I am at it, I will also be replacing the motor mounts, as mine are gone, install a new clutch, install a new throw out bearing and pilot bearing. I also need to replace the transfer case because 4 wheel drive has stopped working. I have a couple of questions before I go any further with what I have been working on. I have the engine ready to come out - except for the fact that I still need to disconnect the fuel lines from the fuel rail. I have a disconnect tool for a newer style Dodge but this one will not work for disconnecting the fuel line on the MJ. What type of tool do I need for this or is there just a special trick to doing it without a tool? Secondly, I have fairly easy access to the local Pull-A-Part salvage yard. This is where I plan on getting a replacement transfer case for the MJ. I have already looked through their inventory and they only have one MJ and it is an 86 model. They do, however, have several Cherokees on site. I really don't know a whole lot about transfer cases and was just wondering is there was a particular one I should be looking for. Can some one suggest a good year model to pull one from? Are there distinct marking to tell them apart? Any information will be greatly appreciated. I will post new pictures as soon as I get to a good point in the process so that I can start updating the build up of my MJ. Thanks - KMAPRO

No on the aftermarket exhaust. I have no clue how old the oxygen sensor is. I am betting it is the original one. This was a hand me down truck... As far as the sound when the clutch is out, I haven't checked the fluid level in it lately. I am willing to bet this might be the issue because it grinds a bit when going in second gear when I first start out. After it has warmed up a bit, it shifts smoothly.

First off 87 MJ 4.0 I noticed that when shifting through the gears, except 4th - 5th, I hear a small back pressure pop. Almost sounds like a misfire. Any one have a clue what could be causing this? Next - When sitting at a red light and the truck out of gear, I hear this light knocking, but when I push in the clutch, the sound goes away. What is this?

Well I did get the valve cover changed out and the new Felpro gasket installed with minimal problems. I am a bit curious though, from everyone's postings, I should have had 11mm bolts. The only 11mm bolts I had were the ones where the wiring harness attached - the rest were all 10mm. That rear bolt on the driver's side is a pain to get to. OK, I did check all the tubing and they were all clear. I do still have a leak, but I feel pretty sure that it is a rear main seal. Now, I just need to find a way to get the oil pan to break loose and change out the rear seal. I will try the suggestion above to see if I can get that to work. Thanks to all for their help and suggestions...

Well, I went ahead and picked up the valve cover from the 96 Cherokee at the local parts yard. I was able to get all the hoses and the fitting for the PCV hose that goes in the intake. I only had one problem during the whole process. I made the mistake of only taking an 11mm socket, a screw driver and an adjustable wrench - no other sockets. As it turned out, at least on the one I was working on, the last bolt on the drivers side (closest to the firewall) was a 10mm. Is this standard or was it just a fluke? Anyway, one of the other guys on the lot was kind enough to lend me a 10mm to save me another trip out there. I will also go ahead and check all of the other points mentioned in this thread. Thanks for everyone's help.

Will the 96 cover fix my blow by problem? I am tired of putting 2 quarts of oil every other to three days... I think the valve cover is leaking down the back side of the motor as well. I originally thought it was the rear main seal, but I now believe it just to be the valve cover. At least I hope so. I had every bolt out of the oil pan and beat on the oan for over 2 hours and still did not get it to bust loose.

OK, I am headed out tomorrow to pick up a valve cover from a 96 Cherokee to go on my 87 Comanche. Anybody know, off the top of their head, what size socket I need to take with me? I just don't want to have to fool around in the dark looking at mine tonight... At least, I am hoping to go get one. The local Pull-A-Part has 2 96 Cherokees on their lot. They do not list whether or not they still have the valve covers on them though. Also, I have located a 98 4.0 valve cover as well. Will this work on my 87 4.0?

Yeah, as mentioned, I do have a bad ring on the number 2 piston. I am just hoping that this can be a quick inexpensive fix that will allow me to get by until I can get the engine in my Dodge replaced - then I can yank this engine out and do a total rebuild on it.

So, I am assuming that when I go get the valve cover gasket, I should get one based on the newer valve cover as opposed to the original 87 model? I know NAPA has rings, but I don't have the time for the tear down, machining and rebuild. I am having to use this truck while my other truck is down with a blown engine. Just like my Daddy used to say, "Everything I've got - I either have to fix it or fill it up"....

I know I am going to get bashed for this, but I don't have an air filter in there right now. It was that way when I got it a couple of months ago and I just haven't spent the dineros to get one yet. BUT - I do get quite a bit of build up in the bottom of the air box. My best guess is that the air filter getting gummed up would explain why there wasn't one in there to start with. I plan on going to the local pull-a-part this weekend. Hopefully, I will be able to grab a VC and all that I need so that I can try to get this oil leak stopped. And YES, I will also grab an air filter while I am out.... Thanks for the link and I will let you know how it goes.

OK, I had a posting on here somewhere talking about an engine swap, but I could not locate it with just a quick look around... This is my 87 Comanche. I am having to put a quart of oil in it about every other day. I think I know where the bulk of the oil is coming from, but I don;t really know how to fix it. Here are a few pictures so that maybe y'all can help me out: Most of the leak seems to be coming from the top driver's side of the engine - right around the vacuum thingamajiggy (sorry, I am not a mechanic, but I am learning): A close up view of the area: Directly below the area: I also think I need to replace the rear main seals, but they are not the biggest source of the oil leak: Accumulation of oil deposit on the frame rail next to the vacuum area: Now, I do know that the engine has a bad ring on the number 2 piston and I am having to run an anti-foul adapter so that I don't foul the plugs every 100 miles or so. The vacuum attachment is right above this cylinder as well. Is this why I am getting so much oil presence in this area? Any and all help would be greatly appreciated.

Unfortunately, the oil leak is only one of the problems. I have a bad ring on the number 2 piston. It keeps fouling out spark plugs. I finally just bought one of those No-Foul adapters and it has worked fine for a month or two now. It also has a hole in the manifold as well. I would like to just yank this engine out and rebuild it, but I can't be without it that long. I am just hoping that I can find a good running engine that I can replace it with. That way I can pull the original engine out, have it machined and get a little more grunt out of it. Thanks for the tip on the valve cover gasket. I will get up under it again tonight and take a good look at it. I will already be good and oily as I have to drop the oil pan on my Dodge to see how much damage I did to it...I am assuming that the whole bottom end is gone on it.

Pretty much all over....It is really so bad, it is hard to tell where the leak is coming from. I'll post a pic of the front diff and you will see how bad it is. Wouldn't let me post the pic, but you can follow this link and see the pic: http://www.comancheclub.com/forums/viewtopic.php?f=7&t=19145

OK, I have decided that I need to go ahead and replace the engine in my 87 MJ. It has the 4.0 in it now and I plan to go back with another 4.0. I need to do this now because my other truck (01 Dodge Ram 1500) now has a blown motor. Seeing as this is my only other mode of transportation (a side from my wife's Suburban), I need to get the oil leak stopped and the number 2 cylinder repaired. My plan is to find a motor from a salvage yard or similar venue. I basically just plan on bolting it straight up and not going through it. I will take my current engine and go through it for a total rebuild. I am not a mechanic, so I am asking y'all what you would do to the new engine before it goes in? I know the standard fluid change and spark plug change, but what else would you do to it before you bolted it in. Keep in mind that I am only looking to use the new engine until I get my Dodge motor replaced and my old 4.0 rebuilt. All I need is a reliable running engine that I don't have to put a quart of oil in every other day and will last me about 6 months or so. I am hoping that I can perform the motor swap in just a weekend. Thanks in advance **EDIT** What all year model engines will directly bolt in my Jeep? I think I heard 86 - 91 4.0, but I am not positive. What all models can I pull from? MJ, XJ, etc...