Toyota Repair: 2003 Toyota Corolla - Sound while driving

Question
QUESTION: Hi, Ted.

I have a 2003 Toyota Corolla S. It is a 5 speed transmission with 156k miles on it.

I have a problem that has developed in the last month.

Here is my issue.

Lately I have been having a noise only while driving and pressing on the gas. The noise goes away if I take my foot off the gas or press the clutch in. It is only present in 2nd, 3rd, 4th & 5th gears. NO noise in 1st gear. The noise doesn't seem to get louder with speed.

The noise sounds kind of like a lifter type noise. There is no noise if the car is not moving, nor is the sound present when just idling.

I took it to a shop to check the transmission checked, don't know exactly what they checked, however they told me the transmission needs to be replaced, as well as the clutch. They said the gears appear to be fine, because it doesn't jump out of gear.  

I don't know exactly what the manual transmission has in it that it can go bad and need to be replaced, I can understand a clutch, though.

Thank You for any help.

ANSWER: I assume the shop that said the transmission needs to be replaced checked the fluid, at least I hope so since it is the first thing to do, at the same time the fluid should be drained and inspected for any metal particles in the oil and on the magnetic drain plug, what you are describing does sound like a differential gear problem, a clutch won't cause this type of noise, neither will the transmission gears, noise accelerating or decelerating is most likely involving the differential/.

---------- FOLLOW-UP ----------

QUESTION: Hi, Ted.

Update: this afternoon I took it to actual transmission shop they put it up on the lift and had it running while somebody was inside of it, the transmission was making a lot of noise while on the lift.

The the owner of the transmission shop brought me out so we could both listen to the noise and he described the problem to me. stated it was probably a pinion bearing, but wasn't 100% certain until the transmission is taken apart.

Answer
Thanks for the reply, I tend to agree with that diagnosis but advice against repairing or rebuilding yours, parts are very expensive, check into getting an exchange unit instead, at least this way you know the price upfront and you won't have any "surprises" once the transmission is out and apart on the bench which may result costing more than a remanufactured exchange.