Forgive me if this gets longwinded but here goes my story. I had problems getting into gear at a stop about six months ago. The clutch was also chattering pretty badly when engaging and the dealer diagnosed that I needed a new clutch. Lucky for me (I think) a friend of a friend is a Mercedes mechanic and i was able to have him replace the clutch on the side to save some cash. I replaced the flywheel, clutch, pressure plate, slave cylinder, and pilot bearing. The truck drove great. Still a little picky on going into first at a stop but not bad. About 3 months ago a noticed that it was getting more difficult again. I knew the the fluid needed a change so i figured I would give that a shot. I replaced it with pennzoil ATF. No change if not a little worse. I could tell from driving it and others posts on here that it seemed that the clutch was not disengaging. I decided to bench bleed the master cylinder as recommended by many. It helped for about a day. I spoke with the mechanic that did the clutch for me and he said the symptoms sounded like a master cylinder. So i replaced the master cylinder. There was a noticeable differance for about three days. Than the problems with the clutch not disengaging came back. I don't see any signs of leaking at the slave cylinder (which was replaced with the clutch). i don't know what to try next. I definetly feel like the clutch isn't disengaging because It is difficult to put in gear with the engine running. The shifts from 1-2 and 2-3 are slow to go in as if the trans is waiting for the right rpm to sync up. Also I have started to leave it in first when coming to lights and hold the clutch in because it is so hard to get in gear and when the truck comes to a stop with the trans in first and the clutch all the way in I can feel the engine drop a bit as if it was still engaged to the drivetrain. The truck drives fine for the first few miles while things are cool but as soon as it heats up the problem comes right back. any thoughts on what would cause this. I am really baffled. Why would it get worse as it heats up? Could the ATF fluid in it be too thin when it gets hot? I appreciate any help you can give me on this

 

Check bushings underneath the dash and look at the fire wall for flexing.

 

Can you clarify what clutch fluid you are using? You say it is ATF whereas I would have thought it should be Dot3 brake fluid.

 

OMG I missed the ATF statement. It must be brake fluid, never ATF.

 

Thanks for the replies guys. I think I may have been unclear. I am using dot 3 synthetic brake fluid in the clutch master. The ATF is in my gearbox. I was wondering if as the gearbox heated up and the fluid got thinner if it could affect the syncros engaging. I don't know probably a stretch. I am tempted to change the fluid out for synchromesh. Sounds like many have had luck with that.

 

You have other problems than synchros.

ATF will be ok in the transmission.

Did you check what I suggested earlier?

 

Not yet. Hopefully tomorrow. I don't see why it would get worse as it is driven longer though.

 

Ok I checked the bushings and the firewall. No signs of play or flexing there. I thought of something else though. When I replaced my master cylinder and bench bled it. I had already bled the slave cylinder. Is it possible that when I attached the quick connect onto the slave cylinder connection at the trans that air got into the line. I assumed that it joined together so fast that it wouldnt allow air to get in. Should I have bled the whole system again? If I bleed it now do I need to bench bleed the master again first? Assuming the air could have traveled to it.

 

You are not fast enough.

Speedy gonzales is not fast enough.

Road runner is not fast enough.

meemeep.

Bleed the entire system.

 

So today I went to bleed the system again. I figured I would bench bleed the master cylinder again and then the whole thing. So I got under the truck to disconnect the quick connect at the slave cylinder. As I went to depress the white sleeve to release it as I did last time I noticed it was gone. It doesn't appear to be jammed down in the fitting or anything as far as I could see. All I can figure is that maybe I cracked it last time and that it has fallen off. So I tried to use various things to push in and release it with no success. I finally gave up on that before I caused more damage. I did gravity bleed the system and saw some improvement. I really wish I could remove the master so I could see if any air has made its way in there but I guess I am out of luck there.

 

Well i thought there had been an improvement. I just drove it to work this morning and nothing has changed. I had found a video on the web by a company called Technovations that makes replacement master and slave cylinders for these trucks and in their video they stated that the slave cylinder must travel 5/16 of an inch to properly disengage the clutch. I measured mine to have at least 3/8 of an inch of travel yesterday before and after I bled it. I am wondering about the possibility that the pilot bearing is sticking and causing the input shaft in the trans to keep spinning even with the clutch disengaged. I did give the guy that replaced my clutch a new pilot bearing to put in and if i understand the way it fits together correctly he would need one for the new flywheel so he wouldn't have had to struggle to remove from the old flywheel and taken a shortcut and just left the old one. Any thoughts that this could be possible.

 

Yes a sticky, dry or tight pilot bearing can cause it be hard to shift and it can get worse when hot. If you end up removing the trans again make sure to notice the front of the input shaft where it enters the pilot bearing, it may be damaged, its a common failure. Clean the shaft with some Emory cloth as best as you can.

 

Thanks for your advice. I am really starting to suspect that is the cause. It is just a shame that I would have to pull the trans to see for sure. Its a 4x4 so you know how much work that can be and it's a bit out of my confidence level so that means big money to a transmission shop to fix it. Is there any tests i can do to be more confident that that is the cause.

 

Well i finally got the truck in to a transmission shop. They said it seems like the pilot bearing is hanging up. They also said that when they see this it is usually because of the bearing getting damaged upon installation of the transmission because of misalignment. They want $850 to drop the trans and replace the bearing. If it has damaged the input shaft of the trans it will be an additional $800. How likely do you think that is? I did get in touch with the guy that did my clutch. He of course denies any issues getting it aligned or having to force it together. He is willing to pull the trans and replace the bearing for $300. Who knows maybe it was just a defective part. If the shaft got damaged what is the likelyhood that it could be cleaned up with some emory cloth or something similar. I don't know what he will do if the input shaft is trashed so I guess it is a bit of a gamble to have him attempt to fix it.

 

Already you are hanging the guy that did the job.

Why trust a transmission shops say so?
If there was damage on installation it would have showed up sooner than 3 months down the road. Plus you pissed around with it for 3 months.

Have it removed and inspected.

If I was the original installer I'd tell you to. well anyway.