First I would like to say hello to everyone and thanks for all the knowledge and information on here. With that said, I have a 1991 F-150 4X4 with the M5OD (Mazda 5-speed) transmission and a 302 engine with 145,000 miles. I recently purchased this truck and was told it had a clutch put in a short while back (how long? I don't know) but it has a whizing sound coming from what seems near the shifter boot location. It does it in all gears and gets louder the more RPM's the engine is turning. It does it when the clutch is push in or out and when first cranking the engine it is not there but it seems shortly after (maybe when it starts to warm up) the sound starts. Also, the sound goes away sometimes when downshifting and slowing down but then immediately returns. Everything seems to work fine but there is just this loud anoying sound to deal with, and I was just afraid there may be a bearing going bad. Any help would be greatly appreciated.

 

Sounds like the rear shaft bering to me... Mine did the same thing before I dropped my ZF-542 on my F-250. Plenty of people forget to rent the bering puller or don't have one and don't replace it when the clutch is redone. I still have a little "whizzing sound" in mine but it got alot better after clutch and bering replacement are done. The bering is on the block in front of the clutch and fly wheel assembly.

 

Are you talking about the bearing supporting the shaft leading into the transmission housing?

 

He's talking about the pilot bearing, which is in the end of the crankshaft.

 

Thanks, but should I go ahead and replace the throw out bearing while I'm in there or is it just a waste of money with it being so new.

 

If the clutch really is new then the throwout bearing should be new as well. See if it spins smoothly and replace it if it doesn't.

 

I plan on dropping it this weekend and I hope it is just a simple issue instead of (my normal luck) having to have the whole tranny rebuilt

 

yeah the pilot bering is what I am talking about. Sorry I was heading off to lunch and had a brain fart trying to remember the name of the bering! I'd leave the throw out bering unless it doesn't spin free and smooth... it shouldn't be a whole tranny rebuild. I guess you could have a bering out inside the tranny. I am lucky enough to have a Ford Tranny Mechanic on my list of friends and he just does what the tranny needs... Not all the extra "recommended" fixes. Well just let us know how it goes and what the verdict is. That way other users can use this thread in the future.

 

I just talked to the parts store and for $169.99 they have a clutch kit which has everything including the pilot bearing plus free rental on the puller and the dealer had the gasket for the rear of the transmission for $7.00 so I think I will take it out and go ahead and replace it all while I'm in there, especially for that price because you never know what people are going to tell you to sell a truck.

 

Check the bering puller!!!! The first one I rented was broke and didn't work to take out that little pilot bering! I've found that the bering pullers get abused especially on the smaller bering set-ups!

 

Hmmm... I'm curious


If it is the shaft support bearing or pilot bearing, wouldn't the sound go away when the clutch is engaged?

The bearing and the shaft would be spinning together, so there would be no rotation in the bearing itself.

I have nothing else to add, just had this thought.

On edit, I guess I do have a thought. Are you SURE it is clutch related? Does pushing in the clutch have ANY affect on the noise? If it has no change, then I would look somewhere else for the possible cause. Maybe a pulley bearing on the front of the engine, or possibly the starter motor not disengaging the flywheel, or something rubbing on the flywheel.

 

I just guessed it was something in that area. After crawling all around the truck the noise is by far the loudest right around the front of the tranny. Now, I do know for sure that pushing the clutch has no effect on the noise other than when pushing in the clutch the RPM's go down and the noise gets quieter (but don't go away). Something rubbing on the flywheel would make sense but I won't be able to tell that until this weekend when I drop it and there again since I have it out I'll replace the clutch stuff just to be sure.

 

WOW! what a job that was! After pulling everything out it was obvious that whoever had put the last clutch in, had not put in the pilot bearing and it was in bad shape. I also went ahead and put a new flywheel in it and now everything works and sounds great. Thanks to everyone for your help.

 

here is a huge update!!!! I haven't had a chance to reply because of a huge amount of work lately but I didn't give it a "good" test after replacing everything and the noise was still there! I researched on here for a while and found some articles about the air pump stuff causing the same sounds and feel. What I found was that the small pipe that comes off the exhaust goes up to "something" that is connected by a rubber hose. Well, it had come off. Pushed on the rubber hose and put on a hose clamp and the noise was gone. At least I now know I have all new clutch components under it. Thats what I'm telling myself to make me feel better about the money.

 

Well If your pilot bering was in bad shape as you say it was... Then it's a good thing you opened it up and replaced it before it went bad and caused you bigger problems. Good to know about the air pump noise! And thanks for updating your post.