based on your nickname i assume you have a '95 YJ (same here). to replace the throwout bearing you need to take out the transmission, once is off you remove the fork and then replace the bearing. you can remove the t-case or not, either way you'll have to empty the fluid or it will leak at the rear output splines (unless you have a slip yoke eliminator). if you take the t-case off first you also need to empty the transmission fluid as it seals on the input shaft of the NP231 where they mate.
you can check the service manual - i didnt and i found out a few things along the way
I took the t-case off first as i did this with the Jeep on it's wheels - i'll try to list the steps here from memory:
- drain fluids from t-case and transmission
- unbolt the driveshaft u-joint straps on the yoke at the rear axle and remove the driveshaft
- unbolt the mount screws on the crossmember (3 of them - these are the ones for the transmission mount, not the ones holding the crossmember to the framerails) - for the 3rd one which is the anti-toque mount you will need to use a 19mm wrench on top of the crossmember to be able to unbolt the nut.
- support and slightly lift the transmission with a jack right in front of the crossmember
- unbolt all 6 crossmember bolts and remove the crossmember - ignore the rust on the framerails :) - hopefully your bolts will come out just fine
- at this point you can lower the jack a bit so you can reach all the nuts and bolts easier
- unbolt the straps for the front driveshaft at the t-case and push it forward just enough that you can set it to the ground
- unbolt the 2 nuts holding the slave cylinder - remove the slave and hang it carefully out of the way
- remove the t-case shifter link - you can use a big screwdriver or a small prybar - it is a push-in type with a ball at the end that presses thru a plastic piece on the t-case
- unbolt the t-case from transmission and remove it - at this point if you did not drain the fluids you'll get flooded (don't ask how i know).
- from here on i suggest you have some sort of a dolly with a jack on it unless you're quite strong - the transmission is quite heavy and with the Jeep on the ground would be really hard to handle due to the uncomfortable position there.
- you will need to remove the transmission shifter and the t-case shifter - the transmission shifter you can go about it 2 ways - there is a cross bolt or setscrew that holds the shifter on the short lever coming out of the transmission - i didn't do it this way so i can't offer much advise if you want to take this route. the other way is to remove the 4 bolts that hold the lever plate on top of the transmission and that will come out with the shifter. The t-case shifter i think is held in place by 3 nuts or bolts, no big deal there.
- remove the bolts that hold the access panel at the front of the bellhousing (there are also 2 Metric 12 nuts and bolts as well, on the bottom of the bellhousing, these need to be removed also)
- remove the remaining M12 bolts on the bellhousing (5 or 6 i believe).
- you're ready to slide out the transmission - i'd say be very careful if you do this by yourself, it is heavy - using a dolly and slide out the transmission is the best solution if you are doing it this way.
- once the transmission is out you can remove the fork and then replace the bearing - not a whole lot to explain here, it's pretty straight forward. One thing to he careful about is the clip that holds the fork on the ball opposite to the clutch slave - don't lose it when you pull out or work with the fork. the new bearing will come with new clips so you don't have to worry about those. put some grease under the new bearing where it seats on the fork as well as at both ends of the fork on the transmission side (where the slave pushrod and the ball at the other end sits) - don't put too much. the bearing should have grease inside where it slides onto the guide around the input shaft - if it doesnt you need to put some grease in there, there is a slight area in the center there where you can have grease - once you slide the fork and bearing back in remove the excess grease that is at the end of the input shaft on the splines - that will end up on your clutch and make it slip. when you push the fork back in make sure you hear a click on the wire clip when it goes over the ball opposite to the slave cylinder.
At this time you might want to check and replace the input/output seals on the transmission and t-case (and probably should anyway since they are fairly cheap and who knows when you'll take all this off again - most likely one of them already leaks). also check the rear crackshaft seal (behind the flywheel) - mine was toast and had to be replaced - again, since you have the transmission off you might want to do it, however in this case you'll need a clutch centering tool or you wont be able to slide the transmission back in.
now it's time to put the transmission back - everything in reverse order with a few notes:
- have a jack under the oil pan to have the transmission and engine at the same level
- i made a 6'' long rod with M12 thread at one end and had it screwed in one of the holes on the top of the engine where the bellhousing gets bolted on - made it out of a 1/2'' rod i had and slightly grinded a bit off to get it down to 12mm (otherwise is 12.77 and the 12 mm die won't work over that - i believe the thread is M12x1.75 but i am not 100%) - this made a world of difference as it slided and rested on this rod while i could rotate the transmission a bit to center it onto the clutch. I tried without this before and i was unsuccessful.
- If you dont take the starter off, make sure you have 1 of the big bolts in the access panel before you bolt down the bellhousing to the engine - otherwise you wont be able to rotate it back in place.
- everything else should go in the same way it came out but in reverse order
* Don't forget to put the fluids back in (and if you reuse the old fluids which i don't recommend make sure you don't mix or switch the t-case with the transmission)
* when you drain the NP231 do not use the chain tensioner access cap which is underneath about half way, there is a drain plug somewhere on the other side of the front output yoke (towards the rear of the vehicle).
that's all i can think about - i might have missed a thing or 2 but i am pretty sure most of it's here.
hope this helps.
EDIT: geez, i guess i got carried away - that was a long post
