CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Parts of a transmission?

I have a 2005 Nissan Muran (86k) that I take to my regular mechanic. I dropped it off this morning for an oil change. When he called to tell me the car was ready (I work nearby) he told me that I had a transmission leak.

However, when I went to get my car he told me the specific part that had a leak was the right axle seal. Is that part of the trans?

Also about 3-4 months ago I had some front end work done becausing I was hearing a loud humming noise. Both front wheel bearings and cv joints/boots were replaced but still have the noise. My mechanic told me that it might be coming from the differential and to have Nissan check it out under their CVT extended warranty. Is the/a differential also a part of the transmission?

I don’t mind going to a Nissan dealer - but I don’t want to sound like a complete idiot when I go. I also don’t want to be bamboozled either.

Anyone’s help explaining the parts of a transmission (specifically a CVT) would be sincerely appreciated.

The “transmission” is called that because it “transmits” the power of the engine to the wheels.

You can think of the CV axle as the line that hooks the transmission to the wheels. So it isn’t part of “the transmission” but part of the action of “transmitting.” The engine spins. That spins the transmission. The axle connects the transmission to the wheels so they spin too. (Not all axles do that - some are just passive axles and are sort of just pipes that the wheels spin on. But they can’t transmit any power).

The differential is basically part of that link. The problem is that whenever you go around a corner the wheels on each side of the car have to spin at different speeds. (The outside wheel actually has to spin faster than the inside wheel). The differential is basically some gears that allow that to happen.

You can have a differential that is outside of the transmission. But they are sometimes built into the unit called the transmission. So in technical terms a transmission is always different from the differential. But in practical terms, as on your car, it can all be integrated into the same hunk of metal.

Explaining is a CVT is partly beyond what I could or would type up (could take a book).

There are various websites that tell you “how things work” and many of them are great. They can include simple descriptions with diagrams, some of which can be animated. You can get a clear picture of how transmissions work, including CVTs and how differentials work etc.

Normally I would tell you to find your best local transmission shop and take the car to them. But CVTs are not very common and many shops might not have a lot of experience with them. At the very least, however, I would call around a little. The problem is that you could take it to a dealer and there’s a good chance they they won’t even have anyone who knows much about them. They’re likely to tell you that you just need a new transmission. Then they don’t need to know anything except how to remove and old one and stick on a new one.

I agree 100% with Cig and tip my hat to an excellently written reply.

Take it to the dealer. Let us know what they say. We do care.

Thanks guys for both of your comments. I’ll google the “how things work” websites to see if I can get a better idea.

Nissan has an “extended” warranty on their CVT transmissions because of well known problems. Even though my Murano is a 2005 with 88K - the warranty is for 10 years/120,000 miles. It wasn’t an official “recall” but service bulletins were issued to all dealers.

So I’ll take it to the Nissan dealer and HOPE they tell me I need a new transmission - because it’ll be on their nickel…

Consumers usually have one perception of what extended warranties cover and dealer service departments tend to have a completely different interpretation…If the problem is just a leaking axle seal, that repair is likely to be on you…

Thanks for you input. I have no interpretation of anything regarding my question - I didn’t even know these parts existed! :slight_smile: BUT, I don’t like going into any service department completely ignorant as I’m already behind the 8 ball being a woman.

Now some of you might not like what I just said, but the women in this community know exactly where I’m coming from…

We feel your pain!! Like a duck in a shooting gallery…

Hello All

I haven’t had time to call Nissan but in talking with a few guys I know - they said because my car is 2WD (and not AWD) - I don’t have a differential?

I tried “Googling” Nissan Murano Differntial and the only parts that popped up are for rear differentials…

You have a differential.

The 2WD model is front wheel drive. Nothing about the above changes based on that. You axles are “half shafts” with 2 CV joints each. They plug into the differential - which is probably built into the same unit as the transmission - and each one has a seal.

In most instances on front wheel drive cars the transmission and differential are in the same case and the entire unit is referred to as a “Transaxle”. The Murano uses the JATCO JF010E CVT3 transmission and the differential is in a separate case.

From what I’ve read on issues relating to CVT systems (I have a Dodge Caliber with a JATCO JF011E) the differential seals are not part of the Nissan CVT warranty, and in some cases inner differential seals have failed, causing transmission issues that have not been covered by teh extended CVT warranty.

UGH!!! This car is becoming a money pit and it looks like it’s time to trade it in and go back to Toyota (I had a RAV4 that had 172K before transmission went).

Anyone in the Chicagoland area looking for a used car - stay away from the 2005 Nissan Murano. And in a few weeks, stay away from WHITE 2005 Nissan Murano’s because it might just be this nightmare I currently own.