Need input from people who have a firm grasp of manual drive trains!

Discussion in 'The Garage' started by sixstanger00, Mar 31, 2014.

  1. sixstanger00

    sixstanger00 Member

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    Hey guys! Haven't been on here in forever! Still working on my 4.3 stroker build but for now, I've got a non-SN95 related dilemma...Please read this initial post THOROUGHLY before commenting! Also, I need people with a firm grasp of how manual drive trains work (specifically in the mechanical sense)!

    Quick backstory:

    A friend of mine who's a hardcore Mitsubishi enthusiast bought a 2003 Eclipse GTS (V6, 5-speed manual) a few months back for $500. Owner said it would rev up in any gear with no vehicle motion, and suspected a bad diff. He even started the car up for us and it ran like a champ (except for not being able to move in any gear). Anywho, $$ was paid, title signed over and the car was on a trailer to my friend's garage to start the tear down. The more I thought about the problem with the car, the more I suspected that it was a bad clutch, because I had just recently helped my wife replace the clutch in her '92 Mazda MX-3, and it exhibited the exact same symptom.

    Upon tear down, further evidence suggested that the diff was OK: No metal flakes or particles in the tranny fluid when it was drained, no visible sign of damage to the diff housing, axle splines, or axle spline openings. Once the tranny was out, we quickly discovered that my suspicions were correct; not a shred of kevlar on the the clutch disc!

    So a brand new F1 Racing Stage II clutch was installed, new CV axles, new hub assemblies & new radiator/hose.

    After the reassembly, everything went to an absolute hell of physics-defying symptoms: (these problems are not sequential; they are all problems we have currently observed)

    1st problem:
    Engine OFF: Car can be rolled freely forwards and backwards in any gear. With car on jack stands, we spun the wheels by hand and no unusual noise coming from the tranny or diff.

    2nd problem:
    Engine will not start! New battery, new terminal connectors TIGHT, power comes on, but when the ignition is activated, starter clicks HARD and then a complete loss of electrical power. Moments later, the power will return but extremely weak. Also, + side of the battery occasionally sparks pretty violently when starter engages.

    Apparently, a few other GTS owners experienced this problem, and managed to get their cars started by hooking up jumper cables. We gave it a try, and sure enough, the engine fired up. No CEL! However, this trick didn't work everytime; we managed to only get it started twice like this. The other attempts were just like without the cables; spark on the + side, hard click by the starter.

    3rd problem: Engine ON, car on jack stands: Wheels spin free when in neutral and clutch is out (I realize this is normal, but it does rule out the differential as a suspect, and sense there's no clicking or rattling from the gearbox, it also rules out any input shaft/output shaft probs). HOWEVER, engine struggles to maintain idle speed even in neutral and no load on wheels! When placed in any gear and clutch released, engine stalls abruptly and DOES NOT spin wheels at all.

    I wasn't there when they actually installed the new clutch, but I oversaw the reassembly from tranny to hubs. My friend assures me that the clutch was installed correctly, even after I shot a few queries his way:

    Was alignment tool used? Yes
    Was pressure plate mounted on flywheel dowel pins? Yes
    Was clutch disc facing the right way (raised-center side facing tranny)? Yes
    Clutch fork re-installed in bell housing correctly? Yes - it only goes in one way
    Clutch fork release spring re-installed correctly? Yes
    Clutch-slave cylinder bled after reassembly? Yes
    New tranny fluid? Yes - based on Haynes recommended weight
    Starter good? Yep - had it tested personally at the local Advance...darned thing nearly jumped off the tabletop.

    Sorry of the long post, but I honestly am completely stumped here, and I can't even begin to fathom how the fudge this problem can even exist mechanically!

    Any insight would be appreciated!
     
  2. Tommy92

    Tommy92 Active Member

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    If the clutch is okay and adjusted properly, I think the only thing he can do is take the transmission apart. Does the drive shaft rotate when he rotates the wheel on jack stands?
     
  3. RichV

    RichV Well-Known Member

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    I bet there is a broken shaft inside the tranny.

    When you move the wheels, do the driveshafts move?


    When you had the tranny out, can you spin the input shaft? Does the output shaft spin when in gear?


    For the running issues, I would make sure the engine has a good chassis ground.
     
  4. Pete@FTR

    [email protected] Active Member Preferred Vendor

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    Sounds like something is busted inside the transmission.
     
  5. lutter94

    lutter94 Well-Known Member

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    If the starter is good, and battery is good, you must have bad cables or clamps.....
     
  6. sixstanger00

    sixstanger00 Member

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    Eclipses are FWD, so it's "axle" IS it's drive shaft. (CV axles). The axles are directly meshed to the wheels hubs, so there's no way to spin the wheels without spinning the "drive shaft." (unless the axles are broken, which they aren't - they're new.)

    We didn't try to spin the input shaft on the tranny while it was out, because at the time, there was no reason to suspect anything was wrong with it. The old clutch was pulled and was completely devoid of disc material, so it was logical to conclude that the "revving without moving" was because the pressure plate had nothing to clamp to. Also, I once had an input shaft bearing go bad in my T5, so I know first hand what kind of noise those things make if they're bent/broken. If there was input shaft damage, the tranny would have been noisy when the wheels were spun, or they would have "locked" when the input shaft binded on the output shaft.

    HOWEVER, in regards to the OUTPUT SHAFT:

    Don't know how familiar you are with FF drive trains, but starting from the front wheels, everything is meshed together:

    Wheels to hubs, hubs to axle splines, other end axle splines meshed to differential, diff. ring gear directly meshed to output shaft, output shaft meshed with gear shaft/input shaft, input spline meshed with clutch disc.

    That said, the output shaft ALWAYS spins when the wheels spin (unless your diff is bad, in which case you won't be spinning anything - not even the wheels/axles). Now when we performed the wheel spin test, I could hear the internal gears turning in the tranny, so to my knowledge, both the input/output shafts were performing normally. Nothing unusual like a grinding or clicking....just sounded like gears moving, which is normal on any tranny, FF or FR.

    I agree that it sounds like a bad ground on the starting issue. Apparently 3G Eclipses hate having their clutches replaced....it's so common for this starting issue to arise just after a clutch install, that 3G owners have name it the "Mystery starting problem after a clutch install." :D
     
  7. RichV

    RichV Well-Known Member

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    I don't work on FWD vehicles much, but I know enough to understand what you're saying.

    My thought was either splines in the hub, splines in the diff, or internal shaft in the trans. If the drive wheels move even if the car is in gear and the motor is not turning, do the driveshafts move? If yes, the problem is internal. You can try if it changes in different gears, 1-5 or R. Maybe there was a trans issue and a PO tried to rebuild, and forgot to put something back in?? You never know. But you do know the trans needs to be removed and either broken down/fixed or replaced.
     
  8. sixstanger00

    sixstanger00 Member

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    FW drive trains are basically identical to RW drive trains except they don't employ a drive shaft & pinion gear; everything else - including how it works in tandem with everything else - is the same. The axle setup on a FWD is no different than that of a Cobra R's IRS, with the exception that the diff is inside the tranny, and the ring gear meshes directly to the output shaft, rather than meshing to a pinion gear attached to a driveshaft (because in a FF, they aren't needed). :smiley:


    I thought maybe that's what you were suggesting, but as I said in the original post, new CV axles & new hubs were installed, so I knew the problem wasn't external.

    I don't know if I mentioned this in the original post, but when the drive wheels were off the ground and the engine running in neutral, the wheels would spin freely. I know this is normal, even when the car is in neutral due to inertia from the spinning input shaft, but this did prove that power could be transmitted to the wheels through the diff, so it, nor the axles/hubs could be faulty.

    Also, it did occur to me to try other gears, including reverse in all of the tests I've mentioned. In each gear, the results were the same.

    I'm trying really hard to explain this paradox as easily and simply as I can, but it's a bit difficult (so I've discovered) for people to see as clearly as me:

    Basically, I'm getting two completely different symptoms that should physically not exist simultaneously because by mechanical law, they contradict one another:

    CONDITION 1:
    Engine - OFF
    Wheels elevated - YES or NO....pushing the car forwards/backwards with a load on the drive wheels yields the same result.
    Tranny in gear - YES

    Under these conditions, the drive wheels can still be spun freely without "locking" as they should when the car is in gear. I was trying to explain the scope of this problem to my wife this evening; there are 2 ways to make the internal components of the tranny spin - power can either come FROM the wheels TO the tranny via the diff & axles (by kinetic energy - in other words, spinning the wheels to spin the transmission), or the power can come from the engine via the clutch assembly, but in either case, if the engine doesn't spin free, the tranny can't (unless it's in neutral, which it wasn't).

    CONDITION 2:
    Engine - ON
    Wheels elevated - YES or NO...releasing the clutch in gear in both instances immediately stalled the engine with no forward movement whatsoever...not even a "lurch."
    Tranny in gear - YES

    Under these conditions, the car will not move when the clutch is slowly released.

    So here's the paradox:
    Tests have shown the clutch to be functioning correctly: 1) When the pedal is depressed, the engine maintains idle without stalling, and gears can be shifted in and out of with no unusual resistance. (Linkage is OK, too - when gears are selected, the normal clicking from engagement/disengagement is heard from inside the gearbox) 2) When the car was in neutral and the clutch pedal is released, the drive wheels spin, due to the inertia from the spinning gears, so the pressure plate IS clamping the disc correctly, and the input shaft on the tranny cannot be damaged, otherwise this action would be very noisy and very violent, due to the shaft "wobbling." So thusfar, we've eliminated 1) clutch 2) input shaft 3) differential 4) axles 5) hubs

    So at this point, we're left with only one suspect - the output shaft & gears in the tranny. But if the output shaft isn't meshing with the differential ring gear properly (as it wouldn't be if say, a bearing was bad or it was bent/broken), how could the wheels be turning when the car is in neutral?! And how would we be able to spin the drive wheels ourselves freely?! As I said, the diff ring gear is meshed with the output shaft gears at all times, so when the wheels move, it moves. If the output shaft were damaged in some way, we would hear noise in the gearbox when the wheels were turned and/or the wheels would "lock" (as they appear to do when the engine is ON) due to the shaft binding against the input shaft and/or ring gear.

    Now, I saw where someone with a Golf GTi had a similar problem with the engine running, and the tranny ended up having a broken shift fork which had gotten lodged in the input shaft. However, in this case the guy did not experience the "rolling freely in gear with the engine off" problem. In fact, if the transmission is "stuck in gear," then the abrupt halting experienced with the engine ON should also be experienced with the engine OFF (because the tranny is simply stuck in one or more gears).

    This problem truly has me dumbfounded, because I cannot see how these two problems can mechanically exist at the same time. Whatever is wrong has something to do with WHERE the power is coming from, because when the power source is me turning the drive wheels by hand with the engine off, the car behaves as if the clutch isn't working correctly and/or gears are not engaging correctly.

    But when the power source is the engine, the car behaves as though the clutch is working correctly, that the gears ARE engaging correctly, and that the problem must lie in the differential.


    In summary, I've performed numerous tests and demonstrated that no drive train issues SHOULD exist, yet two clearly do. Two issues that should be physically impossible to experience at the same time. :shocked:

    (Sorry for another long boring post...I've been obsessing over this problem since week before last):embarrassed:


    EDIT: I also forgot to mention that when we spin the drive wheels by hand, we can hear the rotation of the internal components in the tranny. No unusual clicking or scraping sounds.
     
  9. sixstanger00

    sixstanger00 Member

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    !!! UPDATE !!!!

    For anyone who was interested, we resolved the issues:

    Starting problem: Bad connection on + battery cable. Cleaned cables & replaced connector.

    Rolling in gear with engine OFF: Bad differential. Removed diff from the tranny and discovered the spider gears had lost nearly all of their teeth. Thankfully, no internal damage from the broken off teeth. Quaife limited slip has now been installed and car is on the road.