The transmission seems to be slipping.

ANSWER : Hello. From what you describe, it would appear that your transmission is beginning to slip. This can be caused by many things. The first thing I would do is check the vehicle’s transmission. Automatic transmission use fluid pressure to operate, and will have all sorts of issues if the fluid is low or dirty. If the fluid checks out, I would then move on to looking at the transmission itself. It may be possible that one of the components, such as a sensor or solenoid may be going out and causing your issue. It may also be possible that the transmission is simply worn out and can no longer hold the engine torque, perhaps due to a worn clutch pack, valve body, or torque converter. In these cases of removal and overhaul of the transmission is required. You may be able to continue driving the vehicle, however, because it may cause the symptoms to worsen over time if the issue is not quickly addressed.

ANSWER : It would be a good idea to check to be sure that the fluid level was not overfilled. Too much fluid creates shifting and operational problems just as too little fluid will. So, the level should be carefully verified. If the whirring noise is from the transmission (it could be wheel bearings for example), such noise could be from the torque converter, oil pump, or other rotating elements. The noise would have to be heard first hand by a mechanic to pin it down. If the transmission is not shifting properly, it could be as simple as a valve body issue (typically the valve body is replaceable on the vehicle) but there are also many other causes of shift difficulty such as broken or worn bands, failing clutch pistons and so forth. Some of these faults can be determined by using external gauges to measure internal hydraulic pressures within the transmission when you shift. Transmissions can be repaired; you won’t necessarily need a "new" transmission but yes, admittedly, such repairs can be costly. If you want to get a definitive diagnosis and get information about repair options, just request a transmission shift and noise diagnostic and the responding certified mechanic will help you with that. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : Hi Jose: Thanks for your question. Below is some additional information in addition to that sent to you by John yesterday. Installing used parts, particularly a part as complex as a transmission, is not the best practice. If you have a transmission fault, the first thing to do is get the cause of the fault professionally diagnosed because some transmission faults are easy to fix, such as low fluid level, replacement of burnt fluid, or needed fixes on engine controls or wiring (transmissions are electronically controlled). YourMechanic offers that service as a transmission diagnostic and you can schedule that at your convenience.

After you know, for sure, what is wrong with the transmission then a decision can be made as to the most economic and effective repair strategy. That is, if the fix is not amongst the simple causes of transmission breakdowns, but rather is due to something like a worn out band, or a leaking clutch piston, then the transmission has to be removed, completely overhauled and re-installed, usually with a new torque converter. Without a diagnostic, even installing a new transmission may not resolve your issue if the fault lies in an engine control or electronic control component and this is why you need to first get the problem identified. Hope we can assist you with this.

ANSWER : Hey there. If you have manual transmission, this is almost certainly the clutch slipping. It is wearing out and used gently, it will propel the car forward, but it cannot hold the torque when you accelerate harder. The clutch will need to be changed. If neglected, eventually the car will not move even when accelerating gently. For verification of what to do next, a certified technician can inspect your transmission and advise you on a repair.

ANSWER : Hi there. In most cases when you overfill the transmission fluid it can cause excessive foaming of the fluid or possible internal component failure due to excessive pressure inside the hydraulic lines. Sensors like the speed sensors however are rarely impacted by this situation. However, in regards to the possibility of probability of this; I would say perhaps a 10% chance.

ANSWER : Hi There,
This is a known issue in this generation Ford Focus and some Fiestas with the "Power Shift" transmission and there have been numerous recalls and lawsuits. Although, it is would be difficult to determine how much longer your transmission will last given the fact that you have many new parts, I would not recommend junking the car as it may still provide some valuable life left for you. I would recommend taking it to the dealer to see if these parts may be covered under the recall.

ANSWER : This may be a simple adjustment to the throttle kick down on the transmission. It may be out of adjustment or there may be a problem with the shift solenoids in the transmission. The kick down is a simple adjustment that should be done by a qualified transmission mechanic to ensure it is correctly done. If you’d like a second opinion on this, consider YourMechanic, as a certified technician can diagnose the issue with your slipping gears and suggest what to do from there.

ANSWER : This is possibly a transmission shifter adjustment issue (5th gear, non-engagement). The noise issue may be related, but it is potentially serious regardless. You don’t mention what kind of "transmission problems" caused you to have the clutch repaired, but that problem may be related as well. Regardless, you should have the slipping issue inspected by a professional, like one from YourMechanic, before driving it further.