I have a Cummins NTC 300 with a eight speed transmission with four low speeds forward and reverse. Forget anymore the exact name of the transmission. Am I headed in the right direction ? Number one pull the floor mat and sheet metal from the top side. Next unhook the air lines to the tranny from the shifter and remove the shifter handle by pushing down and twisting to the right ??? Remove drive line and the PTO then put a transmission jack under it and unbolt tranny from bell housing. Next will I have to pull the bell housing off to get the pressure plate and clutch out ? How much clutch plate should be left on the disk before you would replace it while out ? Now as I look at the back of the crank what will I look at as far as a seal ? Now before you give me your info , how big of drip before you would replace the seal ? As I back down the drive here at home it will give a drop about every ten feet,but right after parking in the shop maybe a shot glass will drain out on the floor. But checking the oil every day it never seems to drop any on the dip stick. This is my last drip on this truck and it will be free of drips for a while I hope at least.
You have to pull flywheel to get to seal. is a complete circle one piece. if you pullthe bell housing you MUST repeat MUST get someone with a dial indicator to reset the bell housing and center it or face destroying your trans or maybe rears. It doesn't take much to be out of line and you cannot sight it in. Also clutches are only $260.00 to $350.00 and you need to look at resurfacing flywheel. Pilot bearing and release bearing. All said, you may only have a front seal leaking in the transmission. ckeck the lube level there.
Checked it out this morning and it looks like a guy wouldn't have to pull the bell housing off. I am glad you told me about setting a dial indicator up to restall it, I never heard of that before. You would think that if it was that important they would have guide pins in the block or somehing like that.
They do have dowel pins, but you are told to remove them, align the bellhousing radially to the crank, then drill the holes out to the next bigger size and install new bigger dowels. Tolerance is between 6 thou and 12 thou depending on which bellhousing you have. I always found if you took the bellhousing off and put it back on it will be within tolerance, but always checked with a dial indicator just to be sure. George
clutch Ive heard of using a dial indicator on the flywheel, but that doesnt mean thats not correct. Take the flywheel and have it turned (trued up) usually about $100 As someone stated, make sure you find out where this leak is coming from, before you go to all that trouble and I mean trouble, if this is your first time Change your clutch and pressure plate, you can get a reman for around $350, get a easy pedal, ask for that, they will know what you mean. They usually come with wooden wedges to hold it aligned, dont take them out, until the tranny is in Throw out bearing, you need to replace it, as stated Mark all your air lines, so you will know where they go back In my area, the shops charge about $1200-$1500 for a change out P&L, if a bunch of air tanks have to come out, its more Without a truck tranny jack and this is your first time, its going to be hard, not impossible, we have all had to do it this way at one time or another I would offer a suggestion and it hasnt been that long ago that I was totally against this, Go to your parts store and get them to get you 2 containers of Barrs Leak rear engine seal stop leak, (dont let them sell you a different brand) should be around $10 a bottle. This is kind of new, so the parts store will have to look for it. I have used it in two trucks and an old Drott 40 excavator with a Detroit 4-71 and it stopped the leak or slowed it down a lot. I wouldnt use it in a new model truck, but its OK in these older engines. Last suggestion, this is a major job and major PITA (take it to a shop and get them to do it) to do and if you dont get that rear seal installed straight, its going to leak again. You may have to put a speedy sleeve on the crank, if its got a groove worn in it Good Luck
Reading all these posts, it sounds like there is confusion between the FLYWHEEL Housing mounted to the engine block, and the BELL housing mounted to the transmission. Honestly neither of them needs to be seperated from it's assembly and realligned for this job .Autocar can unbolt the bell housing from the flywheel housing, drop his trans down and get to his clutch,flywheel, and rearmain seal. Once you are at the seal, many Cummins rear main seals come with a plastic sleeve inside them that lets it slide over the crank and directly in to place with ease, (however, I haven't done a NTC). If you don't know how old the clutch is, it's worth changing.
After more inspection I see theres some leaks on the P.T.O. mounting, looks also like the seal between the pump and p.t.o. may be dripping also so I believe first I will fix these items and then see. I am pretty sure thou that it is leaking at the main seal. I looked up through the clutch adjustment plate and I can see the front of the tranny and see the shaft coming out and there is no oil around that area but ahead of the fly wheel there is a drain hole in the bottom of the bell housing and it shows oil drips.