tourrunner

First post, so first things first. Thank you to all who make this forum the wealth of info that it is. I'm a carpenter, not a mechanic, but managed to replace my master/slave clutch cylinders last Spring with your help.

I've had my 4Runner for about a year now, and it's been a great daily driver. But I just spent several hundred bucks at the shop to not fix some problems I've been having lately, so I'm hoping I can get some feedback here to isolate the issues. I'm experiencing 3 specific symptoms, but am not sure if/how they're related.

1) When idling and driving in gear, there's a faint rhythmic knocking that goes away when the clutch is in. It's been suggested to me that this is the main input shaft bearing that's going bad. I recently changed the transmission fluid to hopefully buy some time.

2) There is an intermittent squealing sound in R, 1, 2, 3rd that only occurs when I'm in gear and accelerating. It's becoming less intermittent and more constant, and I've been told this may be my throwout bearing.

3) When I get to about 50 mph, the whole truck starts rumbling pretty badly. It's just as bad when the clutch is out as it is when accelerating, but if I'm in gear and not accelerating, it all but disappears. This makes me think it's not a tire balancing issue -- I'm on 31" tires, btw, but have no idea what the gear ratio is at... assuming it's 4.10. I've recently rotated the tires but nothing changed. So, maybe a u joint? Or something to do with the tranny?

The engine seems to be in good shape. Good compression in all cylinders and just installed new plugs and belts.

I really appreciate any ideas/insights. Please bear in mind I'm very inexperienced, though I've done a little bit of reading and have a Chilton manual to reference.

So if I DO, in fact, need to replace bearings/seals, is this something a relatively handy guy could reasonably expect to do on his own? From what I gather, I'd have to drop the tranny.

I'm not sure where to get the bearings (as a set?) or how to know which tranny I'm ordering for, so advice on this is sorely needed. And... I've got a lot of tools that work well on wood, but am lacking even some basics when it comes to mechanical. Though I'll gladly buy or rent (tranny jack) what I need for this project and future use.

Thanks in advance.

cman1

iTrader: (1)

id take it out ,take it to a reputable shop,and let the pros do it.youll need gear pullers,and basically have to take it completely apart.welcome!!!by the way.oooorr,trade in some wood tools for some gearhead tools and dive in! hehe.my 2c...tranny guys get what theyre worth.let them do it.or just buy a re-built from marlin crawler swap em out.

SCToy

Marlin crawler sells a rebuild kit for the transmission. I started out like you, but pulling the input bearing is not easy, I had to weld the gear puller to the bearing to get a grip on it. They are a tight press fit.

You may be better off looking for a used transmission to swap in. That is doable with basic hand tools, some jacks and the ability to turn a wrench.

tourrunner

Thanks guys. So you're thinking the symptoms are consistent with transmission bearings then, yes? If swapping out trannys seems like the best idea for my (in)experience level, how do I know which one to get? I'll be checking out Marlin Crawler's stock later today...

Any ideas on the rumbling at high speeds?

cman1

iTrader: (1)

my experience has been the pilot bearing will screech and scream...the throwout bearing will growl.

James Woods

iTrader: (1)

Get a used tranny off CL and rebuild this one, it will give you a newly refurbished transmission and some experience, and since the used one is in the truck, you wont have to rush it.

It's not really that hard, take pics of the shafts before you tear them down so you have a reference point. I would suggest buying a shop press and some clam shell bearing splitters, other then that you don't need any special tools.

I would agree with the pilot bearing most likely being the screeching sound, the shaking could be your u-joints, I would recommend checking them out.

phildelfino

wow, a lot going on.
good advice though on buying a used tranny and rebuilding the one you pull out.
while switching trannies you can replace the pilot bearing, clutch, throw out bearing, etc, etc, and take the drive shafts in to get the u joints checked, replaced.

craig's list or ebay for the proper factory manual will be very helpful.

bruno4turbo

i just learned all this at school! so big bearings (ie. throwout) growl, but it'll only make noise when it is engaged (clutch pedal depressed) small bearings scream (ie. pilot)

to your #2 problem, if it goes away in 4th gear its your input to output bearing not throwout bearing

as for rebuilding it, if you drop the transmission, and buy the proper kit for it (check driver door jam for model), then bring it to a shop its a hellava lot cheaper (don't open any packaging or take any part of your transmission apart, costs more, because they can't verify that all the parts are there if it's taken apart). as for doing the work your self, don't, you'll be looking at a really big project. as for just putting a new one in, it may cost more to buy a rebuilt one but thats your choice. shop both options before you decide.

as for the rumbling, u-joints you'd feel like you where slamming into gear, also they make a little squeak when rotating(3-4 times faster than your tires), might be an out of balance drive shaft, find a buddy with a truck and tape a bolt to his drive shaft and drive around if it feels the same look into getting yours balanced or getting a new one. if not check all your bushings, even the body bushings to the frame, if they're missing torn gooie or rock hard probably need new ones or re-grease the ones with grease fittings

to truly identify which bearing(s) is/are bad, it helps to know which are where and when they are working, "working" is when the outer race and inner race have opposing forces (running at different speeds) or when there is pressure applied to the bearing.

-throwout bearing: connected to clutch fork, "working" when clutch pedal is depressed (growling sound)
-pilot bearing: from crank shaft to input shaft, working when idling, or in any gear but direct drive (usually 3rd or 4th depending on the transmission) (squeak or scream)
-input to output shaft bearing: as the name entitles, working in all gears but direct drive (squeak) to test if its this, not the pilot, when driving, stop and depress the clutch if it stops making noise after 7 to 9 seconds then its the input to output.

personally your #1 and #2 diagnosis seems mixed up, but i can't verify since i can't hear them lol. I hope this helps you, good luck!

bruno4turbo

i do agree with getting a used and rebuilding yours, its a great project. as for "don't need special tools" not totally true, snap ring pliers are the only way not to destroy a snap ring to get it off. to get bearings off, hold the speed gear and bearing and slam the butt of the shaft on concrete, or sturdy table they'll slide off together. for the bearings on the counter shaft you'll probably need a puller

tourrunner

I'll get one. Wasn't sure there'd be much difference from my Chilton.

The prevailing thought seems to be that getting a used tranny and rebuilding mine is a good bet.

I was thinking photos for reference would be good, too. What would I be looking for re: the shop press? 6 ton, 20 ton? A frame?

I'll take a look at my u-joints, but unless it's something visibly obvious, I'm not sure how to determine if they're no good.

It doesn't feel like I'm slamming into gear, so it may not be the u-joints. I'll check the bushings and otherwise start thinking it's an unbalanced (or bad) drive shaft. You recommend a particular grease and/or grease gun? Will I need a bearing grease packer, too?

Thanks for the details re: where/when the bearings are working. Definitely helps to isolate.

Sounds like it's the pilot bearing, though I'm not getting it in 5th yet. Maybe I can't hear it over the rumbling!
I've got some tools and a used tranny to purchase, so I'm putting the investment in on it. Though, if I've got a bad/unbalanced driveshaft, maybe I should be taking care of that first!

bruno4turbo

take care of the transmission first, then if the vibration doesn't go away get a driveshaft, as for grease i use a normal grease gun for cars/trucks, but use marine grade grease (for boats) but thats a personal choice. never used a bearing grease packer...

tourrunner

I'm on the hunt for that transmission. Thanks for the thoughts re: grease, too.

tourrunner

I found a factory manual on ebay for $50. Apparently it's just "volume 1" but covers the drive train. Worth the money? If it'll walk me through repairs to my truck, I'm thinking so...

bruno4turbo

if its a factory service manual its going to be really helpful, but $50?? it better be a big book haha

tourrunner

No luck on grabbing a used tranny yet. But I definitely have bad rear driveshaft. Having a tough time getting the bolts off though. Any suggestings? Put a torch on 'em?

SCToy

Jack the axle up, spin the driveshaft til the nut youn want to get to is down and the. Put on the ground. Get a closed ended wrench with a pipe on it for leverage. Put it on the nut side and break it loose. Repeat until all nuts are loose. Pb blaster helps a lot. Wouldn't use a torch, its got a seal in the diff quite close to that flange.

tourrunner

Thanks SC. I'll give it a whirl.

tourrunner

Ok... I just found a rear driveshaft from a '88 SR5 V6 4Runner that's getting parted out.

Will this work on my '86 4cyl DLX? I did some digging to turn up that info, but didn't have any luck. Thanks for all the help thus far!

bruno4turbo

put them next to each other that they are the same length, but i don't see why not.
get new u-joints for it regardless of if they look good.

if you have a slip yoke into the transmission instead of flange to flange with the slip in the driveline make sure the splines are the same. but if it has the slip in the drive shaft make sure that it doesn't come out when transporting or that if it does that the yokes stay parallel. you can get a magnetic angle gauge from harbor freight pretty cheap if you have too.

tourrunner

The slip is in the drive shaft on my 4Runner. I haven't seen a picture of the one from the parts truck, but I'm waiting to hear back on it.

Thanks for the info.