Possible rear main leak; clutch is slipping

hawkdriver

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Driving home from work yesterday and put my foot into it to pass a car and clutch slipped a good bit. Changed my oil a few days ago and noticed a few drops of oil on the bellhousing. Didn't see any leaks anywhere that were obvious so figured it may be the very cold weather we have had. Last night I checked the valley and complete top and rear of the engine. No leaks of oil or fuel anywhere. HPOP is new and I rebuilt the fuel bowl while I did that upgrade. Oil crossover lines have a little oily mess around them but nothing I would call a leak. After I parked last night I put a piece of cardboard under the truck and I was getting a drop of oil about every 15 seconds (it was hot). Crawled under the truck and cannot see any fluids leaking down from up above at all. I'm fearing it may be the rear main. Have to drop the tranny for a new clutch now so I may as well do the main seal. I have read that they rarely leak but at 275,000 miles I guess I should do it while I am there. Has anyone performed this task without the $338+ special tool? Any tips? Thanks!
 

hawkdriver

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Could it possibly be an input shaft leak? I put a kevlar pilot bushing in during the last clutch change. Puddle that has been forming smells like oil and not trans fluid.
 

RSG

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I'm no expert, so take this for what it's worth. There is also a plug with an o-ring on the back side of our engines that would be worth checking. Maybe you have done that already. I have 228k and never have changed it. I'm dripping all over again...but it's an automatic. Good luck!
 

hawkdriver

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I have looked everywhere for the source but to no avail. It has to be the RMS. The valley has been dry for a few years after I installed a new HPOP, rebuilt the fuel bowl, etc. Top of the engine is clean. The one and only place I see oil is the bottom of the bell housing/trans. New clutch on the way along with a new RMS, special tool to install it, the correct sealant, new up pipes since I'm going to be in there, and a new slave/master (pre-bled :) ) since mine is getting tired after I replaced it about 7 years ago. Also doing the Hutch/Harpoon mod since it will be down anyways. I'll report back when I get the trans out. Hopefully start tonight after work.
 

bcvickers

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I have looked everywhere for the source but to no avail. It has to be the RMS. The valley has been dry for a few years after I installed a new HPOP, rebuilt the fuel bowl, etc. Top of the engine is clean. The one and only place I see oil is the bottom of the bell housing/trans. New clutch on the way along with a new RMS, special tool to install it, the correct sealant, new up pipes since I'm going to be in there, and a new slave/master (pre-bled :) ) since mine is getting tired after I replaced it about 7 years ago. Also doing the Hutch/Harpoon mod since it will be down anyways. I'll report back when I get the trans out. Hopefully start tonight after work.

Take a good close look at your turbo pedastal area. That can leak and run down the same area and not show up in the valley.
 

hawkdriver

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I am buttoning everything up today. EBPV delete pedestal, high flow/non-ebpv exhaust flange, tightened up my HPX lines, cleaned all of my boots, new RMS, new clutch/flywheel, pressure plate, throw out bearing, pilot bushing, new bellowed up pipes. Cleaned up the valley and the back of the block. Clutch and flywheel were in good shape but it appeared to be oil soaked. This should keep things dry for quite some time I hope. Clutches get expensive!
 

hawkdriver

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I finally got the old girl buttoned up last night. No leaks anywhere. Drove it to work today so I'll check underneath tonight to see if all is well. It definitely drives better. I think the new up pipes as well as deleting the ebpv helped with response a little bit. I installed a Luk heavy duty ceramic clutch kit. I think the 1980 Chevette my mom owned had a stiffer clutch pedal than this lol. Taking a little to get used to. I liked the Southbend I had before but this feels better. A little preventative advice for any fellow 6 speed owners: Look under your dash and check the aluminum bracket that holds the shaft that your clutch pedal pivots on. I knew from earlier clutch replacements that mine was getting worn but it was about to it's breaking point as the repeated clutch pedal applications over 276,000 miles actually wore into the aluminum bracket and allowed a huge amount of play. I would give it another 5000 miles and it would've left me stranded somewhere. Bought a new one at the dealer for $99 and it made a world of difference.

20180127_145508.jpg
 

hawkdriver

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It's been a week or so since I finished up the work under the truck. If your ZF has as many miles as mine does I would recommend changing the input shaft seal as well as the inner boot on the shift tower. I towed my boat (8500#'s) for 4 hours yesterday and she did great. Tows better and gets slightly better mileage it seems. Below is a pic of the leak from the input shaft seal.

On a side note.....this place is pretty dead since the days of old when I joined.

20180214_162902.jpg
 

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