2012 Gt500 Goes into gear, but wont move forward

[devon807]

Tried to do a first gear hit and now the car wont move. any suggestions? All gears go into gear perfectly fine, but when I let out of the clutch it doest do anything, also I no longer needed to use the clutch to get into the gears. SO im assuming a clutch probably? Also the speedo was moving while the car was stationary.

 

[WidowrRacing]

When I broke my trans I had no first gear or reverse and it was the first/reverse cluster gear.
Try starting off in second gear.

 

[Bad Company]

I'm assuming you've tried every gear in the transmission and the car wont move, yet the speedometer is showing as if the car was moving by increasing and decreasing in MPH with the car sitting still. The speed sensor for the speedometer is located in the tail shaft of the transmission and senses the speed of the main/output shaft of the transmission, which is connected to the driveshaft.

I'd be looking at the rear end to see if you wrung of the input shaft of the pinion gear. Or I'd be looking at the driveshaft to see if it is turning or if you've wrung that off. With the car sitting on jack stands, check to see if the driveshaft is turning with the car in gear and the engine running. If the driveshaft is turning the problem is in the rear end. If the driveshaft is the problem you'll see it when you look under the car. The main shaft of the transmission could have wrung off also after the speed sensor, which is allowing the speedometer to work, but isn't transferring power to the driveshaft.

Your car has a two piece steel driveshaft, you could have wrung off the splines at the carrier bearing also. So the front half of the shaft is turning, but the rear half isn't. Hopefully this is what you've done, as it will be the cheapest and easiest to fix. There are numerous aftermarket sources to purchase a 1 piece replacement aluminum driveshaft for your car. It is one of the first things that should have been upgraded as soon as you start adding HP to this car.

 

[devon807]

When I broke my trans I had no first gear or reverse and it was the first/reverse cluster gear.
Try starting off in second gear.

Tried all gears, no dice though

 

[devon807]

I'm assuming you've tried every gear in the transmission and the car wont move, yet the speedometer is showing as if the car was moving by increasing and decreasing in MPH with the car sitting still. The speed sensor for the speedometer is located in the tail shaft of the transmission and senses the speed of the main/output shaft of the transmission, which is connected to the driveshaft.

I'd be looking at the rear end to see if you wrung of the input shaft of the pinion gear. Or I'd be looking at the driveshaft to see if it is turning or if you've wrung that off. With the car sitting on jack stands, check to see if the driveshaft is turning with the car in gear and the engine running. If the driveshaft is turning the problem is in the rear end. If the driveshaft is the problem you'll see it when you look under the car. The main shaft of the transmission could have wrung off also after the speed sensor, which is allowing the speedometer to work, but isn't transferring power to the driveshaft.

Your car has a two piece steel driveshaft, you could have wrung off the splines at the carrier bearing also. So the front half of the shaft is turning, but the rear half isn't. Hopefully this is what you've done, as it will be the cheapest and easiest to fix. There are numerous aftermarket sources to purchase a 1 piece replacement aluminum driveshaft for your car. It is one of the first things that should have been upgraded as soon as you start adding HP to this car.

Will do, thanks! Also, does the fact that I can go into any gear now without the clutch relevant at all?

 

[PC03GT]

Will do, thanks! Also, does the fact that I can go into any gear now without the clutch relevant at all?

That sounds like your trans took a shit bud

 

[devon807]

That sounds like your trans took a shit bud

I think if this was the case i'd hear bits of whatever broke moving around, and the car probably wouldn't be able to be pushed in gear

 

[PC03GT]

I think if this was the case i'd hear bits of whatever broke moving around, and the car probably wouldn't be able to be pushed in gear

The car shouldn't just go into gear while it's running with no clutch. Maybe the clutch is toast....

 

[03cobra#694]

I think if this was the case i'd hear bits of whatever broke moving around, and the car probably wouldn't be able to be pushed in gear

Could be the input shaft, and nothing inside is turning, so no noise. I could be pushed, because no resistance from the engine. Just a thought.

 

[Bad Company]

The speed sensor is seeing rotation of the main shaft of the transmission at the location of the speed sensor in the tail shaft of the transmission. This means the problem is after the transmission. If it is sensing rotation of the output shaft of the transmission, my thoughts are it is either the driveshaft between the transmission and read end, the input shaft of the rear end or possibly the gears in the rear axle. To have the speedometer register speed in every gear means the problem is in the driveshaft or rear axle..................hopefully the driveshaft. Why? It is the cheapest and easiest to fix.

 

[ShelbyGT5HUN]

No grinding, whirring, or squealing noises?

 

[Bad Company]

First let us start over.

1)when you are stating the speedometer moves with the car in gear and engine running, I'm assuming you have seen this in every gear of the transmission and that as you go from 1st gear through 6th gear the MPH of the speedometer is increasing in speed even though the car doesn't move. This is a Yes or No question you have to give us to help you. Does the speed reading of the speedometer increase as you go to a higher gear in the transmission?

2)if the above is true then the mainshaft of the transmission is turning, which means the clutch is engaging when the clutch pedal is released and the input shaft/gear of the transmission is turning the first cluster gear in the transmission. As you move through the gears of the transmission, power is transferred through the most forward gear of the cluster gear assembly to the gear you've selected and locked into place with the shift lever to turn the mainshaft/output shaft of the transmission. You clearly state the speedometer moves, so again I'm assuming the speed sensor of the transmission is accurately seeing the mainshaft/ output shaft rotating.

If the above is accurate and true this points us in another direction to the failure.

3)can you shift the transmission without using the clutch? Yes you can. Now my next question while you're performing this exercise is. Are you doing this after trying to going from neutral without any speed showing on the speedometer head/gauge? Are you doing this with 0 MPH showing on the speedometer? If the transmission is rotating/turning then the synchronizer of each gear will speed up the gear you're trying to engage by using a friction ring so that gear chosen locks to the mainshaft of the transmission effectively changing the speed of the manishaft as you upshift.. Without having the load of a moving car, I'd be willing to say that the synchronizers would allow you to do this without noise, but I'd also expect that the shifter might feel a little heavier in moving also. I'd also expect it to be difficult to downshift without causing the friction ring to grind a bit as you are trying to slow the mainshaft down as you go from one gear to the next lower one.

4)your driveshaft has 2 CV joints. One at the back of the transmission and another at the carrier bearing. Either one of these joints can fail under the load of trying to launch the car with a good set of tires while sitting still. I'd expect you to feel vibration if one of them failed, but if it was a clean break you may not. Again this is if everything else I've covered so far is an accurate assumption on my part of understanding what you are describing to us.

The last thing is the rear end. You could blow the spider and axle gears apart so everything turns from the clutch, to the transmission, to the driveshaft and finally to the pinion input shaft of the rear end. I'd expect you will hear a bunch of noise coming from the rear end when you're trying to move this car under its own power. If you wrung off the pinion gear input shaft then I'd expect a LOT of vibration and noise

Get the car up on jack stands to see that the driveshaft is turning

 

[Bad Company]

Let me explain one thing in a little bit more detail. Yes If you engage first gear while using the clutch and rev the engine up just as if you are driving it then you should be able to engage the next gear fairly easily if you let off of the accelerator to allow engine RPM to drop as you engage the next gear. This is called float shifting in the trucking industry. Without the load of moving the car I think this could be done quite easily because as engine RPM drops it takes less effort for the synchronizer to speed up the next gear as you upshift through the transmission. I don't think downshifting will be easy to do this without grinding/forcing the synchronizer to match gear speed with the transmission mainshaft speed.

Now if you aren't raising engine RPM and then letting off of the accelerator to come close to matching engine RPM to mainshaft speed of the next gear and you're rowing through the gears while at idle.........you probably have a transmission problem.

 

[SSSSSSSSSSSSVT]

Let me explain one thing in a little bit more detail. Yes If you engage first gear while using the clutch and rev the engine up just as if you are driving it then you should be able to engage the next gear fairly easily if you let off of the accelerator to allow engine RPM to drop as you engage the next gear. This is called float shifting in the trucking industry. Without the load of moving the car I think this could be done quite easily because as engine RPM drops it takes less effort for the synchronizer to speed up the next gear as you upshift through the transmission. I don't think downshifting will be easy to do this without grinding/forcing the synchronizer to match gear speed with the transmission mainshaft speed.

Now if you aren't raising engine RPM and then letting off of the accelerator to come close to matching engine RPM to mainshaft speed of the next gear and you're rowing through the gears while at idle.........you probably have a transmission problem.

 

[Bad Company]

Yes you can float shift while downshifting. Why I don't think he is doing this is he would have to match/raise engine RPM for the gear being chosen as you move the stick through neutral.

As you remove torque from the driveline and you float the driveline the stick will easily move into neutral without using the clutch, now to make the downshift without grinding the synchronizer you have to increase the speed of the gear you're choosing next by raising engine rpm with the transmission in neutral. Look at it in this manner, synchronizers are nothing more than mini clutches inside the transmission that use friction to either speed up the next gear of your choice or by slowing it down as your moving the stick from one gear to the next. This is why when a synchronizer becomes worn that the transmission makes noise during the shifting process.

Now if the car being talked about by the OP has a failure in one of the CV joints in the driveshaft, he has removed all of the load while he is seeing his speedometer increasing in speed as he goes through the gears. Without load on the gears he should be able to upshift easily if he works the throttle in the same manner as he would on the street while moving, so he would naturally be dropping the speed of the next upshift gear and the synchronizer wouldn't have too much load on it that to match the speed for the next gear chosen. Now if he is sitting there upshifting gears without using the throttle the synchronizer has much more work to do in matching gears. I'm assuming that during his tests that he trying to get the car to move and its not and he is watching his speedometer increase in it speed readings as if he was driving down a street. So he would instinctively manipulate the throttle in the same manner as if he were driving. If he is doing this then he would be slowing the next gear for the upshift down naturally giving the synchronizer less work to do to match speeds inside of the transmission for an easy upshift. Why don't I feel that the OP would be able to make the downshifts without making noise or grinding is the fact I don't think he is raising engine RPM while moving the stick through neutral to speed up the lower gear chosen.

All Class 8 trucks up until a few years aga don't have synchronizers in them. The recommended method to shift is to push in the clutch, move the stick to neutral, release the clutch, raise or lower engine RPM to either speed up the gears or slowdown the speed of the gears inside of the transmission to then select the gear you want. Now if you matched the speed of the gear selected to the road speed you're traveling and the engine RPM you push the clutch down and move the stick to the gear chosen. If you didn't match the engine RPM for the gear chosen in your mind that you are going to then the transmission is going to grind and you won't be able to proceed with the shift........now what do you do next? Try it all over again until you match the gear to the road speed your traveling with the engine RPM so the stick drops into gear without clashing. In a truck the shifter is moving what is known as a sliding clutch in the transmission from one gear to the next, not a synchronizer, why? Because it doesn't have the extra friction ring in it to speed up or slowdown the next gear. It takes a new driver 10s of thousands of miles to become proficient in doing this. Today many trucks are built with a manual transmission with a computer that talks to the engine computer to complete the shift automatically. Here are two YouTube links of the new automated manual transmissions being tested by drivers with many years of experience driving traditional non-synchronized transmissions. Unfortunately many of the new drivers today can't drive a truck with a traditional stick shift transmission and their driver's license is restricted to them only driving a truck with one of these automated manual transmissions in it. Because it is a long learning process to shift a manual and no two trucks really shift exactly the same it really can take years to do correctly. Older trucks can actually have more than one transmission in them. The main and the auxilary in the worst possible gear combination to learn is a 18 speed main with a 4 speed auxilary behind the main for a total of 72 gears to chose from. This set up is used strictly for extreme Heavy Haul or Off-Road Oil Field Drill support equipment. The biggest combination I have had the opportunity to see was a 21 axle combination truck and trailer that was weighing 600,000lbs. It was having an engine problem with the main tractor and I had to look at it on the side of the road at the bottom of Afton mountain on I64. To move the truck engine was modified roughly to 1000Hp, the trailer had a 600Hp pusher engine controlled from the cab of the truck followed by a 1200Hp push truck to help going over the hills. Transmissions used in this combination was a 18 speed with a 4 speed air shifted auxillary. The auxillary had a stick that didn't move, it had a knob on the top of the stick with the 4 different possibilities at the flick of a switch to shift. Now float shifting this combination is something I wouldn't even begin to try without a lot of training from the driver that was driving it. These two stick/transmission set ups came about in the 50s-60s when you had very low Hp either gas or diesel engines and used transmissions to multiply torque.

 

[Bad Company]

I forgot to say one thing in the post above about float shifting a Class 8 truck transmission is doing the things I described above without using the cluch........no double clutching.......only manipulating the throttle with the transmission in neutral to speed up or slow down the gears before moving the stick into the next gear position of your choice without depressing the clutch a second time. After a while you get used to a truck, you can actually drop 4-5 gears in one movement as your skipping through the gearbox. Now don't do this while taking the driver's portion of a test for a CDL........the DMV inspector riding with you will immediately fail you even if you slide the stick into gear without grinding or forcing the sliding clutch and gear together to engage the gear you selected. Government even tells ya how to drive a truck.......yet the DMV inspector couldn't drive the truck if their life depended on it.

The two video links are actually the computers doing float shifting for the driver. They have a traditional clutch in them with no linkage for the driver's left foot. The clutch is also actuated by the driver's input on the throttle pedal. once the truck is moving the clutch isn't used for any of the up shifts or down shifts. This coming summer I'll actually get the opportunity to drive a truck with this transmission. I can only imagine how weird this is going to be the first time I drive it.

 

[devon807]

Alright so an update, I’ve got the car on jack stands, driveshaft is spinning (both parts) and the Speedo is moving as I go through the gears (without the clutch) so I’m assuming this is means it’s time for a new rear

 

[SCGallo2]

Yep, sounds like something in the rear axle let go. I have an OEM 2008 GT500 takeoff rear axle with approx 58k miles that I just removed from my car. If it gives you options and minimizes down time for you, I'll make you a good deal. If you are in VA, we are within driving distance to make an exchange.

I just installed a custom Moser M88 that I am really enjoying, so that might be an option for you as well.

 

[Bad Company]

Alright so an update, I’ve got the car on jack stands, driveshaft is spinning (both parts) and the Speedo is moving as I go through the gears (without the clutch) so I’m assuming this is means it’s time for a new rear

Unfortunately I'd say you either broke a pinion gear shaft or lost the spider gears in the differential. Otherwise I's say the car would try to move if you'd broke a few teeth off of the pinion or ring gear in the rear.

Yes you will need to rebuild the rear axle. I'd upgrade while I had it apart to a WaveTrac 33 spline differential, but this requires new wheel bearing housing to be welded to the axle tubes. It would eliminate the C-Clips that retain the stock axles for a safety upgrade, along with the fact the WaveTrac distributes torque to the tires under all conditions for better traction regardless if one wheel is not touching the road surface. The downside to the WaveTrac is the cost, but it is inline with a Gleason Torsion or an Strange S Trac, if you have to replace the center section due to a spider gear failure.

Or you can take the route offered above and purchase a used rear to save money. This would also give you time to rebuild your existing rear up at a later date

 

[Vinnie_B]

Go with a Moser M88 8.8" Built to Order Rear End Package if you can. Im going the same route as @SCGallo2. Still up in the air over a WAVETRAC - 33 Spline or Truetrac - 33 Spline

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