depressing newbe question of the day

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1969dodgedartgt

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ok, i have a 318/904. stock
occasionally shes askes me to mash the pedal, if I do this I hear crunching/grinding sounds which seem to come from the transmission. This will only occur in first few seconds of acceleration.

If I mash pedal after im already going about 20 mph, no such sounds.
If I'm gentle in acceleration, no such sounds.

I do not feel any slipping of gears, but dont have my tach on to see (if thats necessary)

fluid level seems fine, though tranny does leak a bit at u joint.

now I have to fight the urge to mash, because I dont want to damage, but I WANT TO MASH.

Is my transmission going? no plz no :prayer:

secondly, can you analyze transmission oil to diagonose wear as you can with engine oil? anyone done this?

thanks
 
Ok, Is the sound like heavy drumming/thumping from the hump area of the floor or a real metal to metal sound? It could be a bad transmission mount (easy fix) that could be letting the transmission shift around or up and hit the floor on heavy acceleration and also letting the u-joint hit the floor. If this is the case, I would look at your motor mounts too. Those bisquit type mounts can easily split and look fine until you put some load on them.

Other than that, I'm not to sure of the sound unless you describe it a little more.
 
Let's not assume the worst without checking things over first. You said the tranny fluid level was ok, how does it smell? How does it look? If it has a nice red color and no burnt smell, let's look elsewhere. If the fluid is dark, getting to a brownish color or has a burnt smell you would have tranny problems.

As for your noise, if the tranny fluid looks ok, I would look at the U joints first. Can you grease them? Do you know how long they've been in there? Check your motor mounts. Are they biskit or spool mounts? Check the one on the right side close. Check the tranny mount. Check your differential fluid level and change the tranny fluid & filter. Check your brakes. Rev the engine and look for anything rubbing or binding along the inner fenders/firewall.

Lots of things to check over before assuming the worst.
C
 
Check you motor mount on the driver side. I replaced mine because of the same symptoms. Have someone give it a 'little' and I mean a 'little' gas with it in gear and foot firmly on the brake. Look down and you may see the motor lift off the mount on the driver side. Let us know.
 
I'd guess that the problem is with the U-joints or the rear end.
I'd park the car somewhere level,put it in neutral,set the emergency brake and turn the driveshaft back and forth by hand.Is there play in the rear end? does it feel like it stops right away against the gears or does it feel like it still moves a bit after the first contact? and can you move the end of the driveshaft up and down where it bolts to the rear end?

Those are signs the rearend has problems and if it's the stock 7 1/4 rear,it's very likely.
 
rob_robinson87 said:
Ok, Is the sound like heavy drumming/thumping from the hump area of the floor or a real metal to metal sound? It could be a bad transmission mount (easy fix) that could be letting the transmission shift around or up and hit the floor on heavy acceleration and also letting the u-joint hit the floor. If this is the case, I would look at your motor mounts too. Those bisquit type mounts can easily split and look fine until you put some load on them.

Other than that, I'm not to sure of the sound unless you describe it a little more.
Click to expand...


sounds like metal to metal grinding, from tunnel area
I'll check mounts tomorrow..
maybe i'll record sounds and post... if i can get good recording
 
clhyer said:
You said the tranny fluid level was ok, how does it smell? How does it look? If it has a nice red color and no burnt smell, let's look elsewhere.

As for your noise, if the tranny fluid looks ok, I would look at the U joints first. Can you grease them? Do you know how long they've been in there? Check your motor mounts. Are they biskit or spool mounts? Check the one on the right side close. Check the tranny mount. Check your differential fluid level and change the tranny fluid & filter. Check your brakes. Rev the engine and look for anything rubbing or binding along the inner fenders/firewall.

Lots of things to check over before assuming the worst.
C
Click to expand...

fluid looks red and good, i've tried rubbing it btwen fingers feels fine. just checked smell, im far from expert but maybe smells little burnt.

I did change tranny fluid when i bought about 3 months ago, brakes have been recently checked and rechecked.

I'll try and check these other things tomorrow in light. how to identify biskit vs spool mounts?


cudadriver said:
Check you motor mount on the driver side. I replaced mine because of the same symptoms. Have someone give it a 'little' and I mean a 'little' gas with it in gear and foot firmly on the brake. Look down and you may see the motor lift off the mount on the driver side. Let us know.
Click to expand...

sounds good i'll check this

67GTConvert said:
I'd guess that the problem is with the U-joints or the rear end.
I'd park the car somewhere level,put it in neutral,set the emergency brake and turn the driveshaft back and forth by hand.Is there play in the rear end? does it feel like it stops right away against the gears or does it feel like it still moves a bit after the first contact? and can you move the end of the driveshaft up and down where it bolts to the rear end?

Those are signs the rearend has problems and if it's the stock 7 1/4 rear,it's very likely.
Click to expand...


thanks i'll try this in light, can you tell me how to identify my (car) rear


thanks guys I'll try this stuff ASAP
 
My bet is it's a broken drivers side motor mount allowing the motor to tip up under hard acceleration and that allows the fan to hit the shroud making a grinding noise. Had that happen quite a few times personally and saw it many other times on cars I worked on when I was young.

If the K frame is the original for the car in your title it is a biscuit type and they are the ones that commonly break. They are a slab of rectangular rubber with studs sticking out both sides. Spool mounts are round and have the retaining bolt going in from the front with a nut on the back.

A real quick easy test to see if it's a motor mount is to open the hood and have a buddy stand beside the vehicle (wearing eye protection just in case) and they you set the parking brake and put the car in drive and hold the brake real tight and give it some gas. If the motor comes up more than 1/2" the mount is broken or oil soaked so bad it is like a sponge.
 
1969dodgedartgt said:
sounds like metal to metal grinding, from tunnel area
Click to expand...

Last time I had this, it was sloppy left and right motor mounts that were letting the exhaust headpipe move up and make contact with the underfloor crossmember rail as the engine torqued under hard acceleration. Sounded for all the world like metal grinding on metal. A new set of motor mounts fixed the excessive engine movement, and a reworked exhaust headpipe was spaced properly from the floor.
 
67GTConvert said:
I'd guess that the problem is with the U-joints or the rear end.
I'd park the car somewhere level,put it in neutral,set the emergency brake and turn the driveshaft back and forth by hand.Is there play in the rear end? does it feel like it stops right away against the gears or does it feel like it still moves a bit after the first contact? and can you move the end of the driveshaft up and down where it bolts to the rear end?

Those are signs the rearend has problems and if it's the stock 7 1/4 rear,it's very likely.
Click to expand...

i can only move the driveshaft a bit when doing this. I dont think there is any movement after contact, I can move the back of the driveshaft up a couple of centimeters at the rear ujoint

the joints look like they need some grease
 
fishy68 said:
My bet is it's a broken drivers side motor mount allowing the motor to tip up under hard acceleration and that allows the fan to hit the shroud making a grinding noise. Had that happen quite a few times personally and saw it many other times on cars I worked on when I was young.

If the K frame is the original for the car in your title it is a biscuit type and they are the ones that commonly break. They are a slab of rectangular rubber with studs sticking out both sides. Spool mounts are round and have the retaining bolt going in from the front with a nut on the back.

A real quick easy test to see if it's a motor mount is to open the hood and have a buddy stand beside the vehicle (wearing eye protection just in case) and they you set the parking brake and put the car in drive and hold the brake real tight and give it some gas. If the motor comes up more than 1/2" the mount is broken or oil soaked so bad it is like a sponge.
Click to expand...


no sign of fan contact anywhere,

I'd say it maybe came up about an inch, I'll try this again looking closer at mount to see if there is tear that shows when load is applied. gotta run now
 
If you can move the driveshaft a couple of CENTIMETERS at the rear U-joint then there's a problem back there. That's nearly an inch. If your front seal on the rear axle isn't showing signs of leaking then I'd say there's a new rear U-joint in your future. Doesn't necessarily mean that's the source of your noise but I'd definitely look int it.
 
'64 Cuda said:
If you can move the driveshaft a couple of CENTIMETERS at the rear U-joint then there's a problem back there. That's nearly an inch. If your front seal on the rear axle isn't showing signs of leaking then I'd say there's a new rear U-joint in your future. Doesn't necessarily mean that's the source of your noise but I'd definitely look int it.
Click to expand...


opps let me correct that, it moves less than 1/4 and inch.
I did find that there is a bolt missing on the back ujoint as you can see in picture below. I'll replace this real soon.

I found two motor mounts, is that all there is? they are the B(isket?) type.

is the transmission mount the one that holds up from below? see pic. This mount looks like it receives a good amount of tranny oil from leak. maybe this is my prob, can i replace by myself without tranny falling on ground? I have very little tools.

my oil looks real good and I dont think it smells (sigh of relief), but the grinding type sound really bugs me.


passenger mount
IMG_2152.jpg

driver side mount
IMG_2153.jpg

some kind of mount holding tranny to engine
IMG_2154.jpg

is that my tranny mount?, look at all the fluid my tranny throws off!!!
IMG_2156.jpg

tranny throws fluid from this seal, and from pan seal, How much to fix? how big a problem?
IMG_2157.jpg

omg missing bolt in drive train, good thing you guys told me to check this...
IMG_2158.jpg


when i have car in gear with brakes firm and give little gas, i do not hear any of the grinding or any thumping noise, so I'm thinking its not the motor or tranny jumping. sound reasonable?
I've heard almost exact same noise from my old friends ford years ago. I was kinda surprised when i first heard it that I remembered his car noise. I dont know what was wrong with his car though.

I'm feeling better but still lost....
 
fishy68 said:
My bet is it's a broken drivers side motor mount allowing the motor to tip up under hard acceleration and that allows the fan to hit the shroud making a grinding noise. Had that happen quite a few times personally and saw it many other times on cars I worked on when I was young.

If the K frame is the original for the car in your title it is a biscuit type and they are the ones that commonly break. They are a slab of rectangular rubber with studs sticking out both sides. Spool mounts are round and have the retaining bolt going in from the front with a nut on the back.

A real quick easy test to see if it's a motor mount is to open the hood and have a buddy stand beside the vehicle (wearing eye protection just in case) and they you set the parking brake and put the car in drive and hold the brake real tight and give it some gas. If the motor comes up more than 1/2" the mount is broken or oil soaked so bad it is like a sponge.
Click to expand...

It does seem that the drivers side jumps up more than passenger side, but thats probably just the mechanics of it...?

time to go replace that bolt....
 
Ouch! fix that missing bolt on the rear end yoke. Also check the flex plate for cracks between all bolt holes (crankshaft and torque convertor end. photo #3. Grey plate bolted to your orange torque convertor) Cracks can make some funky noises under load. toolmanmike
 
The last picture is your problem. If the rear u joint comes loose, it will beat the crap out of the bottom of the car before it flies out into traffic. Most embarrassing.
 
'64 Cuda said:
If you can move the driveshaft a couple of CENTIMETERS at the rear U-joint then there's a problem back there. That's nearly an inch. If your front seal on the rear axle isn't showing signs of leaking then I'd say there's a new rear U-joint in your future. Doesn't necessarily mean that's the source of your noise but I'd definitely look int it.
Click to expand...


replaced the bolt, f_n bolt wouldnt go all way in, started striping. but I dont think its coming out again.

movement in rear is less than 1/8", think it was about 1/8" before
 
grumpuscreature said:
The last picture is your problem. If the rear u joint comes loose, it will beat the crap out of the bottom of the car before it flies out into traffic. Most embarrassing.
Click to expand...


well your right about that being the problem, I stuck a bolt in there and went for test drive.

on mashing pedal, I hear no or little noise, I suppose if that bolt were all the way in, it would consistently be quite.
I'm a bit embarrassed/ and mad about stripping it :<
but happy as hell to know what the problem is.

so now I just need to figure out what to do with it now that its a bit stripped, suggestions PLEASE.. do I need a new differential/rear?

pics....
can you identify my rear type from these pics?

IMG_2159.jpg


new bolt, as tight as i could grrrr
IMG_2160.jpg



so glad I identified problem, Thanks for the help guys
 
Congrats on fixing it! Your have the 7 1/4 rear. It has that funny shape, like a rectangle with one corner chopped off.
 
Also, you might have to carefully run a rethreader or tap through the bolt hole. Don't force it. If the rethreader binds up, stop and back it out. You'll be sunk if you break off a tap.
 
Helicoil it!!! A kit is cheap (in the grand scheme of things) and will not pull out. They're easy to install. BTW use a grade 8 bolt.
 
I'll bet all of you are off base. Bet its detonation (ping) due to over advanced timing and/or crappy fuel. Look at what he describes as symptoms and think for a moment.
 
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