By on March 12, 2013

TTAC commentator hidrotule2001 writes:

Hey Sajeev,

A few months back you helped me sort out a plan of action for my Ford Fiesta transmission problems, and I have another stick-shift quandary I thought you might have some insight on.

My second vehicle is a 2003 Ram 1500 (bare bones work-truck, standard cab, manual everything), which I’ve recently been doing a lot of maintenance on (new plugs, pads, rotors, u-joints, carrier bearing, and a few other things). One issue I haven’t been able to sort out is an odd grinding/squealing I get when the car is in gear at high rpms (3000+) with the clutch peddle fully depressed (on the floor), something akin to what you hear if you come off the clutch with the shifter only part-way into gear.

Everything I can find on forums seems to indicate this is a worn throw-out bearing, but there seem to be a few things that suggest otherwise:
1) it only happens above a certain RPM (3000+), and makes 0 noise if the clutch is put in at lower revs
2) it only happens when in 1st gear, and occasionally in 2nd or 3rd (but much quieter in these cases)

I’ve had two local shops take a look at it, and neither was able to say more than it might be the throw-out bearing, or possibly some other bearing in the transmission, and they wouldn’t be able to say for sure unless they pulled the transmission out. I figure if it’s to the point that the transmission needs to be pulled, I should look at replacing the clutch (since it’s still on it’s first one, with 120k miles), and possibly some other transmission components, but that’s going to set me back a pretty penny (and it seems like throwing parts at a transmission problem is a good way to lighten you wallet quickly). I’ve also noticed that first and second gear are “clingy” and that when I shift back to neutral and/or have the clutch engaged, it takes substantially longer for the RPMs to return to idle than it does in higher gears, on the order of 2 full seconds(I’ve never noticed this in other M/T vehicles I’ve had, or if there was a difference it wasn’t noticeable). I’ve got a video where you can see the difference in time it takes to return to idle, as well as hear the grinding noise, here.  I’ve also found that the problem is worst when the engine is cold, for the first 10-15 minutes of driving after starting.

At the advice of some DodgeForum members I recently took the truck into my local independent shop to have the clutch, throw-out bearing, transmission fluid, and pilot bearing replaced, but my mechanic called back to say he was pretty sure those weren’t the cause of the issue. He’s convinced the issue is coming from something within the trans, possibly the counter shaft bearing, and was hesitant to replace components he didn’t think were causing the issue. His quote for a rebuilt transmission was 1700, with shipping and labor and a new clutch, that would end up around 2700, which is right about what the truck’s worth.

So now the question is, do I…

-Wait things out and see if they get any worse?
-Have the clutch components replaced anyway and see if that improves things?
-Have them pull the trans and hope it’s something easy to replace/fix?
-Look for a used trans and have that installed instead of a rebuilt one?
-Bite the bullet and have a rebuilt trans installed?
-Try my hand at a tranny-pull and see what trouble I can get into?

Thoughts/suggestion/voodoo-cures welcome. Thanks!

Sajeev answers:

You covered all the bases, short of learning how to rebuild gearboxes yourself.  Which is usually the big problem here: nobody knows what the hell is failing until a rebuilder takes it apart and assesses the situation. I consider transmissions (of all types) to be magic boxes of horror that you must never tear apart unless you are ready for a complete rebuild.  Obviously that doesn’t include accessible fail points like the clutch, torque converter, etc that aren’t encased within the gearbox itself.

Maybe you need a new clutch/throwout bearing/pressure plate/pilot bearing, but if your mechanic says no, I revert to my “magic box of horror” tranny theory.

Don’t worry about RPM hanging between gears, that’s part of the engine computer’s tuning. Not sure why it would hang more gears than others, but make sure you are driving the same way (intensity of throttle input, RPM speed before going into neutral, etc) in all gears to see if there actually is a problem. The hang in my Ranger was super annoying in all situations, so an SCT tune cured it…among other things. But I digress.

Back to your mechanic’s recommendation: let the transmission die, don’t change it immediately.  Just make sure you buy a good replacement from a trusted rebuilder.  If your local searches fail, get one from Jasper or a similar national distributor with a good reputation.

 

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry.

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24 Comments on “Piston Slap: Automatic Decisions, Manual Trannies...”


  • avatar
    Zackman

    Sajeev, just how good are rebuilt trannys? I know AAMCO has been doing it for years, and a rebuilt powerglide was virtually bulletproof, but I’ve seriously dated myself!

    I considered a Jasper 2.5L for our old 1992 LeBaron convertible when the old engine gave up at 148K, but for the price, I sold the car for $500 and called it a day after 8½ years of ownership in 2007.

    My thoughts on rebuilt components like these is that nowadays, the game has seriously changed, and “backyard” rebuilds aren’t possible, with “clean rooms” seemingly a necessity, if at all.

    I agree with you conclusion: Replace the “easy” stuff and let the tranny die before considering going deeper.

    • 0 avatar

      Rebuilt trannies are only as good as the shop from whence they came. And if the staff isn’t specialized in your brand’s gearbox, don’t use them. Seen enough of those problems with Ford AODs and AX4Ns to know better: do your homework before you pay.

      • 0 avatar
        raph

        You mean Ford DOA as in Dead On Arrival. My 1st Mustang was a 91 LX with a 5.0 and a DOA, that DOA is the single biggest reason I refuse to buy a car with an automatic transmission.

        I’m not saying it was entirely Ford’s fault but I was on a rebuild the transmission every year program until I decided to convert the car to a manual (gotta love the simplicity of a fox car), by comparison the only transmission troubles I’ve had since then was the clutch issue with the 07-09 GT500 – easily fixed with the excellent McLeod RXT replacement clutch.

        • 0 avatar

          I know that feeling. My avatar had a DOA that lasted about 10 years and 130,000 miles, then it got rebuilt by a pro…someone who made is absolutely fantastic. By autobox standards.

          But, in the end, the T-56 swap was what I wanted, so it got done and the DOA was sold for $500. I consider myself lucky.

  • avatar
    otter

    Your local independent shop is almost certainly correct. Pulling the trans and replacing the throwout bearing, etc. and zipping it back up is going to be a waste of your money. The shops you consulted are also correct in that you’re not going to know what bearing(s) or other components are bad until you tear down the trans. It would be best practice to just replace all the bearings instead of onesie-twosie-ing it. I wouldn’t touch an automatic, but if you’re mechanically adept and have patience and good attention to detail, you could probably rebuild the trans yourself. At least it’s not your only vehicle.

  • avatar
    jaydez

    I don’t know about the grinding. But the hanging revs in 1st and 2nd gear are most likely to leisurely acceleration.

    Since the throws are equivalent to the wheelbase of a Fiesta on that thing you will more likely be in the power band still when going from 1-2 and 2-3 of it hangs like that. It will prevent you from losing too much speed and lugging.

  • avatar
    ismasl

    Hello all. First replay on this site. Lets see if I can explain my self, english is not my first language.
    I would say that your problem is with the clutch disengage mechanism wich I would imagine is a hydraulic one, this failing to completely separate the clutch from the flywheel. First thing to do would be to bleed the system, similar to any brake system, next thing will be to look for a failure either in the master or slave cylinder. If the clutch is cable operated adjust the tension on this.
    Hope it helps

  • avatar

    I have never driven a ford fiesta. With smaller cars though you want to make sure all of the parts are built for a small car. If you have one part that’s made for a longer car, that actually plays a role with noises.

  • avatar
    DIYer

    Bad input shaft bearing or counter shaft bearing on the input side.
    Short of rebuilding the gearbox, I’d try changing the gearbox oil first to see if there is any difference. See if any metal is present in the fluid when you drain it out.

  • avatar
    cdotson

    I have almost the same truck, a 2002 Ram 1500 Quad Cab 4×2 with the 4.7L and the NV3500, so I recognized the lead pic before clicking the link.

    Last summer at about 160k I had my trans swapped for a junkyard unit for a cost of about $1200 installed without a clutch kit despite it being the original clutch. I should have done at least the throwout bearing because it’s occasionally noisy but previously I couldn’t hear it over the rumbling whine I could hear when in neutral with the clutch pedal up. My problem was the input shaft bearing and it was bad enough to hear at idle speed (neutral without riding the clutch), but it was occasionally also noticeable while coasting in gear with the clutch in. It was most noticeable in 1st, becoming decreasingly audible with each successive gear change. It helps to have your window down and be up against a brick wall or at least a concrete barrier to hear the noise better. When the input shaft bearing eventually went it would skip out of engagement with every gear except 4th as the 4th shift collar supported the rear of the input shaft against the midshaft to keep it in line.

    Previously, under warranty at about 16k miles, one of the overdrive shaft bearings went bad and it produced a high pitch whine when in 5th at highway speed that was louder with increasing load. It sounds more to me like you may have the input shaft bearing problem than the OD shaft problem, but in either event I would recommend the “used” trans swap. If you do it sooner your current unit may be worth keeping to rebuild as a hedge against the durability of the used unit, but if it happens to be one of the few bearings set in a blind pocket of the case the outer race may not be serviceable and even a rebuild won’t take care of the problem.

    As far as hanging RPMs between shifts goes I’ve never experienced exactly what you describe when shifting at my typical 2500 RPM, but mine sure likes to hang on runs to the redline. When cold my experience is that the RPMs drop more quickly and I have to shift faster to drive smoothly, or maybe the clutch is just grabbier on cold/damp mornings, but after it warms up I shift more liesurely to allow the engine to match better after the gulf of a 1-2 upshift. Part of this is also the massive flywheels used on truck engines to allow substantial clutch slipping. During everyday driving it seems hard to get used to the slow engine speed changes, but starting on an uphill pulling a trailer trying not to stall will convince you it’s worth it.

    Dodges up until 2001 had horrible reputations for crummy idle air control motors and gummy throttle bodies and that would definitely contribute to engine hang but I’ve never cleaned my TB or IAC in over 169k without issue.

    • 0 avatar

      This does sound eerily similar to the behavior I’ve been seeing (though my problem doesn’t get worse as the gears go up, it gets better; First and Second are the worst, and Thirds is intermittent but 4th and 5th are perfectly fine).

      There’s an auto-recycler here in town that has a listing for an NV3500 w/ 55k on it for $550, which I’ve kept an eye on, should the need arise. I’m half-tempted to pick it up, to see if I can wrench on things myself (though my wife would probably kill me for taking up her space in the garage), but whenever I start thinking about that I also hear whispering in the back of my head saying “LS1 swap…”

      • 0 avatar
        Fordson

        No, he said, “It was most noticeable in 1st, becoming decreasingly audible with each successive gear change” – that means he’s saying the same thing you are.

        Input shaft bearings sound right here…a WAG would be synchros on the lower gears.

      • 0 avatar
        cdotson

        $550 with 55k…snap that baby up! Just make sure it’s out of a Dodge as the GM NV3500s aren’t compatible. I’m pretty sure the part I had swapped into my truck was $750 including freight from the yard outside Atlanta up to the shop in southside Virginia and it had more miles on it.

        I wouldn’t LS1 swap a Dodge truck…a Hemi maybe, but when my NV3500 was going south I was strongly drawn to a TKO trans, if only to fix that infuriatingly low 1st ratio. Now TKO + Hemi, that would be an awesome swap.

        • 0 avatar

          Yeah, an LS1 swap isn’t very realistic, it’s just one of those things on my bucket-list (LSx swap something).

          I had initially thought about doing a Hemi-swap, if I was going to the trouble of replacing the transmission already, but from the little bit of research I’ve done it doesn’t seem like the NV3500 would be able to handle the extra torque output (at least it’s not rated for it), but now you’ve got me thinking again…

          • 0 avatar
            raph

            Save your LSx swap pennies until the FRS and BRZ become widely available.

            It might ruin everything good about the car but talk about a total hot rod – especially if you go all in with a big cube LSX tall-deck block topped off with a sweet set of factory or aftermarket heads and a Holley tunnel ram (or long runner intake or whatever they call – looks like a tunnel ram to me).

            It would be a modern day Opel GT with a V8 conversion.

            Then in about a month or two that the doors, hood, and trunk probably wouldn’t line up after a few hard launches is only part and parcel of the game!

        • 0 avatar
          redmondjp

          +2 on jumping on that $550 JY tranny, IF it is the correct one. It’s easily worth that in parts alone (try pricing out individual manual transmission parts such as shafts and gears).

  • avatar
    Halftruth

    Isn’t this the NV3500 tranny? They put these in a wide assortment of makes/models. Perhaps the maker of the trans may have some more info for this problem. Also, are there sensors that could be causing your slow-to-idle issue when in gear? Could be unrelated to the noise.

    FWIW, I occasionally see NV series trannies on CL for fairly cheap money, might be worth keeping an eye out.

  • avatar
    Omnifan

    Log into http://www.car-part.com and look for salvage vehicles with that transmission. They’ll list the price and mileage. Sometimes, you can check in neighboring states to see if the prices are better for a short drive.

  • avatar
    Wheeljack

    Sajeev – just an FYI: that RPM “hang” you mention is known to calibrators as “dashpot effect”. It’s done to allow the manufacturer to use a cheaper catalyst with less precious metal washcoat since rapid throttle closure causes a spike of hydrocarbons to hit the catalyst.

    It makes driving a manual transmission vehicle especially annoying – some packages are worse than others. A friend had an ’05 Mustang GT with pretty annoying dashpot effect, so much so that it was hard to drive the vehicle smoothly. My 2002 & 2006 Wranglers must have good catalysts on them because they have virtually no dashpot effect – the engine RPM drops instantly as soon as the clutch pedal is pressed.

    I once had a 1998 Mercury Mystique 5-speed as a company car and it was impossible to drive smoothly between the hair-trigger clutch that had no feedback and the massive dashpot effect. Pity too, because it was a fun car to drive otherwise.

    • 0 avatar
      raph

      Odd – I had an 07 GT that was pretty easy to drive – perhaps this “dashpot effect” is the difference I notice between vehicles that are drive by wire and have a throttle cable. It just seems cars equipped with a throttle cable have better response in comparison.

      If that’s the case, I swear Mercedes has to be the biggest offender as it seems the connection between engine and throttle pedal was modeled entirely on the physical properties of the goo used to fill a Stretch Armstrong.

  • avatar

    Hate to say this but you will not know until the gearbox is out. It sounds like the same problem I just went through on the 94 Legacy. Combination of bad input bearing and a bad pilot bearing. What would happen it when you got over 3500 in first and would shift it would sound like a spun bearing. The same when you held the clutch in and revved it. The noise would persist through any gear you flogged. I knew the input bearing was trash because I had the Ubiquitous front seal leak at over 80 MPH as well. I pulled it apart and the pilot bearing was pretty much non existent and had chewed the tip of the input shaft. A full clutch job and my off the shelf spare trans cured the problem. Upon disassembly of the offending gearbox sure enough the input bearing was trash. Of course on a Subaru you change the entire shaft not just the input portion like a NV series trans. YMMV but I would love to see what is going on in there.

  • avatar
    kmoney

    Before you start replacing parts on this i would reccommend that you take it to a shop that specifically specializes in transmissions.

    As someone who rebuilt transmissions for several years, I can tell you that from what you describe the problem can only a throwout bearing and or pilot bearing and nothing in the transmission itself.

    With the vehicle in gear, clutch fully depressed, vehicle stationary, nothing in the transmission is moving. Say in first gear: mainshaft is held stationary by rear wheels being stationary, first gear is engaged holding the mainshaft to the countershaft, thereby holding it stationary, the countershaft is always locked to the input shaft, thus it is also stationary.

    If you google “manual transmission powerflow” this becomes easy to see.

    While I would never dare to say that something like this could be realistically diagnosed over the internet, I would sincerely suggest you find a specialty shop to look at this before buying parts (i just hate to see people waste money like this, as we used to get pulled in units like this from other non transmission shops where it would come in for a bearing and seal job only to find that there was absolutely nothing wrong with the unit itself).

  • avatar
    Moparman426W

    Kmoney, you beat me to it. It’s a no-brainer, with the truck in gear and the clutch engaged, assuming the brakes or parking brake is applied to prevent movement, absolutely nothing inside the transmission can move. Therefore nothing inside the trans can make noise, it’s his throwout bearing. Throw in a new clutch, pressure plate and throwout bearing. Also replace the fluid, because old worn out fluid can make shifting more difficult, particularly when the trans is cold. The most important reason for changing it though is so that the trans will last much longer. I also suggest the truck owner start following the Engine Masters buildup series if he thinks that an LSX is better than a HEMI.


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