manual transmission screeching on acceleration

[maxmileage]

So I noticed that my 5 speed MANUAL transmission seems to be making a screeching sound(like a belt slipping) when I accelerate in the lower rpm range in all gears, especially 4th and 5th. It goes away when rpms get up to around 2500-2750. anyone have experience with this? wondering how long I have til I am forced to replace/rebuild my trans. anyone have any estimates on what it COULD cost to repair replace? or any other less scary things that this could be? Thanks

2001 SE, 5 speed manual, south-west Colorado

[Chuck Tribolet]

What does the tach do when the screeching starts? RPM jumps up, then drops back when the screeching stops?

I'm thinking slipping clutch. If it's really the transmission, there aren't any belts to slip.


Chuck

[maxmileage]

yeah, thinking I am approaching a rebuild in the future. Don't think it is the clutch because my RPM stays true. just the screech. Mostly in fourth and fifth at lower RPM. Clutch seems strong and it pulls solid with no slip when I gun it in all gears. No burning clutch smell, no leaking trans fluid, level of fluid is all good too. If it is the internals of the trans the screech should get worse and become unbearable soon I would think. Do I run the risk of ruining the trans if I don't rebuild it asap? Never had any issues with a manual trans other than replacing clutches and flywheels. I am out of my depths when it comes to internals of transmissions and would definitely be taking it to someone to rebuild if it comes to that. Tough part is trying to figure out exactly where the dang sound is comin from.
Max

[4xq]

Could be a bearing going out. And it would probably do some real damage when it fails. You could have metal filings circulating around in the transmission now - perhaps draining the fluid to see what comes out would be a good idea.

I looked over at car-part.com. Used transmissions run from 149 to 900 bucks. About 400 to 450 in Denver. There is a used one 54 miles from Durango in Kirtland N.M., but you have to call for the price. I would offer the guy 350 and see if he takes it - he probably doesn't get many calls for 2001 Pathy transmissions there. Take a look over at car-part so you know your stuff if you decide to call him.

Swapping is the cheapest route if you can twist wrenches and do the swap yourself.

A quick edit: You would want to put a new clutch and throw out bearing in while it apart.

[maxmileage]

Most def will be doing the clutch and throwout during any trans work. Since I'lll be in there. Thanks for the info on the used ones. I will be looking around and hope to have a good plan before it gets to the exploding point. I will definitely loook at the one in NM. I could drive there and toss it in the back of the truck and hook it up myself pretty confidently, and that price for an easy swap sounds way better than paying for a rebuild. Oh and are these trannies pretty universal, as far as if I get a 4x4, 96 or on FS5R30? Thanks

Max

Again, mine being a 2001

[4xq]

Well, first thing is probably to hit the shop and have them confirm it's what you think. Based on what you've said, it does sound like a transmission problem, but you probably want to verify that. A diagnosis usually doesn't cost much.

The screech goes away at higher rpm because it is spinning fast enough that it really can't screech at that speed. It is a pretty serious warning of problems if it is the transmission. Not sure I would trust it to do a 100 mile round trip at highway speeds. If it were me, I would use another vehicle if you go to N.M., the tow bill back home would be pretty pricey.

When you go to car-part, you will select transmission as the part you need, then it will give you a selection screen. You need to pick manual 4x4, and it will take you to a list of transmissions that will fit - for all years that fit your vehicle. If it is not on that list, it won't fit. The wrecking yards know all about cross fitting parts.

Another thing to check: call a couple of wrecking yards with low prices and ask what the cost is with shipping. Shipping is pricey, but it could end up being just about as cheap. Parts grade A is best - some places don't list parts grades. So ask what warranty comes with the transmission. Most places give a 30 or 90 day warranty, but you pay return shipping. They will get you another transmission if the used one fails. But manual trannies are pretty reliable, so a failure is unlikely.

You probably knew some of that already, so sorry if it got a bit long.

[maxmileage]

Thanks for all the info, I have been looking today at carpart, good stuff. Gonna call tomorrow and see what kinda deal I can make with the guys in kirtland. And I would way rather have too much info than not enough. Thanks again. I will post back when I get further into the deal. Max

[maxmileage]

Well, I went down to a trusted shop here in town and did a road test with one of the mechs. He said based on the symptoms it seems to be the throwout bearing on the clutch. The screech that only occurs under load, the slight grind that I get with the clutch engaged in neutral, combined with no slipping in any gear seemed to point that way for him. He said that the bearing could be screeching when just the right amount of pressure is applied to it, i.e. me feathering the throttle back and forth just right. He also said that the problem coming on in winter points that way for him to, as it is colder and grease gets thicker and such. He said the sound is slight right now(which it is) and they recommended waiting to see what happens by the spring. But, to start with throwout bearing/clutch and go from there. That sounds much better to me that swapping out the transmission right now. I can get a transmission here to durango pretty quickly for good price. called a couple of places and it sounds like the few that are around for decent prices have been and will be there for a long time, so I should be OK if when I do the clutch it becomes obvious that I need a trans swap. Will post back with any future developments. Max

[Chuck Tribolet]

A throwout bearing makes noise with the clutch pedal IN, not with it OUT. With the clutch pedal out, the throwout
bearing isn't doing anything.

Chuck

[maxmileage]

Sorry, Release bearing. With foot off clutch pedal, clutch is engaged, thus release bearing. With foot on, disengaged, grinding would be Pilot bearing yes?

[4xq]

Chuck has it correct; when your foot is off the clutch (assuming the clutch linkage is all ok) the throwout arm pulls the throwout bearing away from the clutch plate, and the throwout bearing stops spinning. Clutch is engaged at that point, and the flywheel, clutch disc, clutch plate, and transmission input shaft act as one unit and spin at the same speed.

If you have a grinding / rumbling noise at that point you may have a bad input shaft bearing as the transmission input shaft is spinning (even when in neutral).

When you put your foot on the clutch, the throwout arm pushes the throwout bearing up against the clutch plate. The bearing starts spinning at that point. New / different noises when you depress the clutch pedal point to throwout bearing problems.

You do have a pilot shaft bushing. The transmission input shaft spins in the bushing with the clutch disengaged (pedal depressed). It's pretty rare for those to make noise, but you would hear it when the pedal is depressed.

Anyway, I'm not sure you have your answer yet, but wait and see probably works best. Either way, you've got your best options figured out.

[maxmileage]

Man, Throwout V. input shaft bearing V. pilot bearing is an oft talked about and even more oft confusing topic here on the interweb. Seems to be confusing to the guy at the transmission shop I stopped into to have my problem diagnosed. Which is pretty disapointing to say the least. Guy was ASE cert too! So, it definitely seems to be input shaft noise and probobly gear noise as well( I get a pretty good rattling/grinding/shaking noise when accellerating in the lower rpms of lower gears, especially second. So I need to stop being optimistic and concede TRANSMISSION FAILURE IS IMMENANT!! I think I am just gonna go ahead and get a replacement trans since I can get it shipped here from Denver for about $450 total cost. Then I can just do the clutch job and swap in the new to me tran. while I'm at it. Was thinking of rebuilding my tran but for a few more bucks than the rebuild kit I can get a certified/warrantied unit to just bolt up. So, again, thanks to you guys for helpin me out here. Amazing how easy it is to get totally misinformed on this stuff, no wonder tran. shops rake it in. Max

[maxmileage]

AND NOW THIS..... So to add a wrinkle to the mix, I started reading up on clutch operation and found that there are now two different kinds of clutch covers. Push Type, and Pull Type. In the R50 is the Pull type (see MT page 9 of Service Manual) This means that instead of the release bearing pushing on the diaphragm spring to release the pressure on the clutch disk , it is PULLING on a reversed diaphragm spring to do the same. I would think that either push or pull that the thrust or release bearing, respectively, would operate in the same manner. Would that make any difference in the pressure that is applied to the bearing while clutch is engaged or dis engaged. Just trying to figure if it could be the release bearing making the sound because of the pull type clutch being basically reversed of the push type. But, I guess with the clutch engaged either way everything is spinning, so release bearing has nothing to friction against. I think I will be getting readdy to order that Transmission now... Thanks again. Max

[4xq]

Sorry, I did describe a push type clutch. Shouldn't have done that - didn't mean to confuse you. As you said, with a pull clutch, the throwout / release bearing will have nothing to push against when your foot is off the clutch, and it will not spin, assuming in the linkage everything is working ok.

I think what the mechanic was saying is the release bearing is not fully disengaging when you take your foot off the clutch. Meaning it is not sliding on the shaft like it should and completely disengaging from the clutch plate. He thinks that the bearing is still spinning some because it rubs, causing your noise. Can't say from here he is not correct.

I was trying to point out that it still could be a transmission bearing. And I lean towards your idea it is the transmission. But, I would take the mechanic's advice and just drive it for now. As long as you are just driving around Durango, you can always limp it home. If you are doing road trips, that is another matter.

It is a much nicer job in the spring on a warm day than it is in January at 20 degrees anyway.