cmpcpro

Hey guys.. I have a strange one for you all.. Maybe someone here has had this issue. I don't get to drive my car very often so it's been sitting in the garage for a couple weeks and when I take it out when it's cold and coast down the three blocks or so from my house to the Main Street I heard a clanking noise echoing off the parked cars as I go by.. I can even hear it in the beginning without them. It only happens for about a mile or so, but it sounds almost like a slack in a gear over and over again. It's hard to explain, but if you were to push your car while it was in park and the noise you hear when the slight bit of slack runs out and it stops at the end but over and over is the best I can explain it as.. The funny thing is after a mile or so it's gone. Quiet and perfect! I've tried hitting the brakes a little, putting it in neutral while it's happening and it doesn't seem to change. Today I drove a few miles and stopped for about twenty minutes and got back in it and it did it for about two blocks and then gone.. The last time I drove the car it only happened the first drive and that was it.. My first suspect would be driveshaft or ujoints etc.. But how could that be if after a mile it's perfect? Then I was thinking maybe brakes or transmission? Has anyone had this happen? It's a 56 98 by the way. It has the 324/Jetaway. Thanks!

MDchanic

Exhaust system heats up, expands, removes a bit of play?

- Eric

cmpcpro

No it doesn't sound like an exhaust sound it's a rotational sound. Something moving when rolling. I just hope it isn't something big like a tranny issue..

oldcutlass

It could be the drive shaft. Give it a check.

Tedd Thompson

Metallic noises really telegraph in these old cars and are hard to locate especially if you are by your self. Very well could be a u joint or a wheel bearing. Two things you can do, start pulling things off and checking them or hold off till the noise gets bad enough to find with your eyes closed. I would probably get under the car (when it's on a lift) and check all the rotating parts.... Tedd

Rocketowner

When you have the driveshaft out ,pack about an inch of axel grease into the end of the front yoke of the driveshaft.It may be just a tiny bit of slack in between the transmission and the differential, letting the driveshaft drift just slightly.
Packing the yoke with axel grease was standard procedure on this model Oldsmobile at our car lot, especially if you had the driveshaft out .The noise that is made (if that is what you are hearing won't hurt anything), but it is annoying . Larry

cmpcpro

Thanks guys! Larry I think you may have nailed it! To me it sounded like the driveshaft was maybe binding very slightly or shaking.. What you said about drifting sounds like the problem!

Rocketowner

That an easy fix if that is the problem,just drop the driveshaft,slide it off the spline at the front and put in enough Axle grease to fill about an inch of the spline.It will push the excess out at the front of the spline as you reinstall the driveshaft ,just be sure to clean that off well.Will be the perfect time to check both U-joints also. I've also seen this help the "clunk" when going into reverse from forward gear. Larry

droldsmorland

Hubcaps? Pull them and look for little pebbles before you dig deeper. Spinners, check for looseness. Check lug nut torque just for Shs n Grs.

cmpcpro

Thanks Larry! Do you think I'll loose much trans fluid? I don't know what they put in it from the rebuild. I'll jack the rear up. Another guy with a 56 said his u joint would make a similar noise only when cold when it started going bad so I'm thinking about replacing those too. I see a front and a rear listed, should I just do both? Drold: thanks but problem was there with old wheels and tires. Now I have brand new wheels tires and caps.

cmpcpro

Hey guys, someone told me their tranny guy told them to run synthetic atf fluid and Lucas transmission conditioner and sealer as the new atf fluid doesn't lubricate like the old fluid did.. What are your thoughts on that? What do you guys run? Thanks!

Rocketowner

You should not loose much, if any fluid by removing the driveshaft. Check the joints ,make sure they move freely in all directions with no tightness or lumps. Also look for rusty residue around the joints. If you are planning on changing one universal joint ,I'd go on and do both.
As far as transmission fluid ,I would stay with (Type "A" ) if is still available. Best of luck, Larry

droldsmorland

Dont switch to synthetic if the trans has had dino juice in it all its life. Once you do a rebuild then yes, you can run synthetic. Just make sure the rebuilder is well aware you want to run synthetic. Then I do recommend it. TCI has a great clear synth trans juice.
I dont recommend snake oils for any transmission or engine. If it leaks fix the leak if it slips fix the slip. If you have neglected the trans service intervals and its dirty and burnt leave it alone till it blows or rebuild for piece of mind.
The old wives tale of the fluid doesn't lubricate as well as the old did; "cuz when I changed the fluid the trans blew shortly afterwards," is caused by pure neglect. The neglected dirty, metal and friction material borne fluid was acting as a buffer for the worn out frictions/steels. EG actually using the contaminate to help grab. Once you drop that fluid and put in clean juice that barrier is gone. Now a weak trans will experience accelerated wear and whats left of the frictions will wear out rapidly.
Take pressure readings, smell and look at the fluid. Pressure reading is like taking your pulse. It will confirm a healthy vs weak trans.

cmpcpro

Thanks guys. The trans was probably rebuilt 5-8 years ago and shifts beautifully. I'll work with the driveshaft first and hope I don't lose any fluid! I don't believe type a is around anymore they use dextron three I believe

Rocketowner

Notice my post about "Type A " transmission fluid said if you can find it.Amazon still sells it but only by 12 Can lots. Dextron will be fine. Larry

cmpcpro

Thanks Larry! I just ordered a case of 12 to have around! The next time I change the fluid I'll be using that! When you rotate the engine to get to the TQ drain plug and empty it how do you refill the converter? Thanks!

cmpcpro

Can anyone recommend the best u joints for a 56 98? I want to do front and rear. Thanks!

droldsmorland

Hands down Spicer. You may need to measure yours to make sure you get the right one. Dennys Drive Shafts can help. The web site shows how to measure a ujoint. Or call him. Nice guy. Spicers web site helpful too. Once you have the PN you can go almost anywhere and order Spicer.
Not 100% sure on the converter refill. If there isnt access above to fill it and install the plug, which I doubt, my guess is to fill the trans 1/2 to 3/4 full. Crank it up and let it run for 10-20 secs. That should fill the converter then add the rest. Warm it up and recheck. Recheck again after a short road test.

cmpcpro

Thanks!

oldsmitty

My jetaway was rebuilt a couple of years ago and I was told to run Dexron VI. Trans runs great on it.

cmpcpro

Thanks! I ordered new Spicer ujoints but I haven't noticed anyone packing the yoke in the tranny with grease. Somewhere I read there was a fitting on the end too. Wouldn't that grease go into the trans as fluid makes it there? Thanks again guys

cmpcpro

Hey Larry,

Quick question for you. If I pack this with grease won't it go into the transmission and mix with the fluid?

Thanks

Chris

Tedd Thompson

Nope.... Tedd

cmpcpro

Thanks Ted! Purely out of curiousity, as I haven't been under there or done anything with these transmissions but if I can remember right doesn't a little fluid come out when you pull the shaft? That's why I asked. Thanks!

Tedd Thompson

If you have much fluid that leaks out the seal is bad in the rear of the transmission. But you would see that leak all the time as the spline won't seal anything..... Tedd

cmpcpro

I see, so there is a seal in transmissions that seperates the splines/yoke from the fluid? So when I see fluid come out of a transmission when someone pulls a driveshaft it's because their seal is leaking? Very good to know! Thank you! Larry mentioned putting about half an inch of grease in the yoke. I don't quite understand; a half inch high but all the way in the shaft or just about a half inch glob total? Sorry for too many questions! Thanks again for the help! Been buying all my supplies for this job! Got my Spicer joints, my Lubrication Engineers grease and my Arbor press all ready to go!!

Rocketowner

Half inch or so the circumference of the yoke on front of drive shaft.It won't take much to make a great improvement.. Thanks Tedd for your answer. The reason you haven't heard of adding grease to the front yoke is, there's not many of us Old Shade Tree Olds Mechanics left around , I am still here and so is Tedd,if he wants to be added to this category. Hey I Am so old that I remember when The hill where they have the water reservoir for our town, Was A Sinkhole. Larry

cmpcpro

Thanks Larry! Is this what they did at the factory to keep it lubed?

Mark57

How easy is it ti get at the shaft seal? Just curious as I have a leak coming from somewhere....That tranny fluid gets everywhere.

Rocketowner

The seal is in the tail shaft on back of tranny where the front driveshaft yoke goes in.Once the driveshaft is out ,you should be able to flip it out easily with a long screwdriver or pry bar. The new seal can be tapped in ,being careful not to bend one side. Larry

cmpcpro

Hey guys, I went to do my u joints today and I noticed something. On the rear joint the two points that bolt to the rear end seem to come with the u joints on eBay, but the joint I have from Spicer which they swear up and down is the correct one just has four regular caps.. Do I have the wrong joint from them? Do I need one with the other hardware? On eBay all the rear joints come with the two caps or covers that bolt to the rear, the clip looking things and the four bolts. Mine doesn't. Thanks for the help!

Ozzie

Here are my comments on all your issues for whatever they may be worth. The slip yoke comes from the factory with a plug in a threaded hole near the U-joint. You can unscrew the plug and screw in an appropriate grease fitting of your choice. If you choose one with an appropriate angle, you can leave it in place and grease it along with all the other fittings. It calls for special lubricant 567196, but I've always used the same grease as the rest of the chassis, and it's worked well so far (about 60 years). If you want to read about it look on page 2-3 of the 1956 Oldsmobile shop manual.
The rear U-joint is bolted to the companion flange at the rear end with four bolts. If yours doesn't have this it is the wrong joint. If you want to keep the car and make your life easier in the future, buy some U-joints that have grease fittings on them. I have only changed the U-joints once on the car. Keep a hand operated grease gun around with some "light" wheel bearing grease in it for the U-joints. Feed the grease in slowly to allow it to reach all extremities of the spider without damaging the seals. Your U-joints should out live you.

cmpcpro

Thanks Ozzie! I pulled the driveshaft tonight and started pulling the u joints.. Unfortunately they all looked to be fine, in the sense that the needle bearings were all fine and the joint itself looked smooth.. When I pulled the shaft about a quarter of a quart of tranny fluid came out and I could see the inside of the slip yoke was pretty much bone dry short of a little bit of grease. I see the screw for the grease fitting, do you know which one I need to keep it in full time? Also, with that much fluid coming out do you think I need to replace any seals in the tail shaft? Thanks guys!!

Ozzie

If there is absolutely no wear on the U-joints you can reuse them by repacking them with some high fiber wheel bearing grease if the seals and retainers are reusable. If there are any shortfalls I'd replace them with greasable joints. The fluid probably indicates that the rear seal should be replaced. The slip yoke should be lubed via the grease fitting to thoroughly coat all the splines. As long as you get a fitting with the correct thread, you can use straight, 45 or 90 degrees; whichever you find easiest to access with your grease gun.

cmpcpro

Thanks Ozzie! Is the rear seal something that is easily done? Is this the seal that goes right on the very end of the tail shaft? If so how would that keep fluid out of the slip yoke area? Thanks again for your help guys!! Life savers!

Ozzie

My response regarding the seal may have been in error. I reread your posts to get a better understanding. If there was no fluid leak around the slip yoke under normal operation the tail shaft seal may be O.K. I was a bit concerned about the fluid spillage upon removal of the slip yoke. My experience is on a '55 and I don't remember the fluid spillage upon removal of the slip yoke. The '56 had some significant changes to the Hydramatic; Hence my uncertainty about the fluid spillage. I'm unsure if this is considered "normal" on the '56. Obviously there is some accumulation of fluid in that area internally. You could probably benefit from the comments of a '56 owner.

cmpcpro

Thanks Ozzie, I had an older guy tell me fluid went back there and that grease would contaminate it, he claimed he rebuilt them and I know he worked for Olds when these cars were new. My stepdad is a 4 wheel drive mechanic he owns his own shop he said if fluid is being pushed out towards the back how is the grease going to make it up front. The slip yoke does have the fitting and inside a long tube where the grease goes down the middle so I think I am going to still grease it like you guys Recomend. But if anyone here knows 56s and can chime in it would be much appreciated

Ozzie

The shop manual says that the lubricant should be applied to the slip yoke until it appears at the breather groove in the rear bearing retainer for the Hydramatic or at the slip yoke welsh plug holes for the Jetaway. The '55 has the first condition. As I said before, many things were changed on the Jetaway transmission. Perhaps the old fellow may be a good source of information if he can remember. When we old guys try to remember things sometimes confusion can happen. I never experienced any detectable fluid contamination on the '55.

cmpcpro

So the drama continues! The front u joint they gave me was wrong. None of the joints in the store under this car fit. I looked up the yoke in the parts book and it says 5668686 should be correct but I have 5668687 and it's not listed so I have no idea how to find a joint for this!

cmpcpro

Well it looks like the old joint is 352 which is really rare.. So now the question is where is this yoke from?! Update: so the three u joints I have found with 352 have outer clips not inner c clips... I'm lost!