Noob question about front wheel drives

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With rear wheel drive vehicles, there are diffs that need serviced. What kind of drivetrain maintenance do front wheel drive cars need aside from regular transmission fluid changes. They don't have front diffs do they?
 
They do. Part of the transaxle.

Biggest parts of a FWD is the CV joints. Rip a boot and dirt gets into the joint and wear happens.

Most FWD have 4 of them. So when you change the oil, you check the boots EVERY TIME. If you catch a ripped boot and repair it you may have no problems with that CV joint.

Some reading for you ---> Transaxle info

Bill
 
Transaxle. Okay thanks!

Does the transmission fluid lubricate the transaxle as well?

How can you tell if your CV joints are shot? My girlfriend's 01 Impala has a loud humming noise you can hear in the front end. I was thinking it was just oddly worn tires but I'm starting to question it.

The sound gets louder the faster you go but after everything is warmed up and you have been driving a while, it is not quite as loud. You can still hear it but its quieter. Also, when driving at highway speeds, if you turn slightly, the sound gets quieter as well.

I was thinking tires, possibly a bad wheel bearing, CV joints maybe? I don't know.
 
Last edited:
Originally Posted By: dsmith41
Transaxle. Okay thanks!

Does the transmission fluid lubricate the transaxle as well?


Yep. For the most of them. Some have a separate lube for the diff but those are few. (some AWD models)
 
A transaxle is a transmission and differential all in one unit. So yes, transmission fluid lubricates everything in the unit. That being said, a small handful of FWD cars have a seperate differential that uses its own fluid. But 95% of them are all-in-one units.
 
Originally Posted By: dsmith41

How can you tell if your CV joints are shot? My girlfriend's 01 Impala has a loud humming noise you can hear in the front end. I was thinking it was just oddly worn tires but I'm starting to question it.

The sound gets louder the faster you go but after everything is warmed up and you have been driving a while, it is not quite as loud. You can still hear it but its quieter. Also, when driving at highway speeds, if you turn slightly, the sound gets quieter as well.

I was thinking tires, possibly a bad wheel bearing, CV joints maybe? I don't know.


Most of the time a bad CV is a grinding when turning.

Humming would/could be a bearing. (without seeing it)

Turning slightly could take/put a load on the bearing and that could change the sound it is making.

Rotate the tires and see if the noise goes away/changes to see if it is the tires.

Bill
 
most of the time, the differential is part of the transaxle. there are a couple of exceptions: the dodge/chrysler LH's (Intredid) the engine is mounted longitudinally in that car, not tranverse like most FWD. A friend of mine had a chevy nova (actually a toyota) that he claimed had a separate differential - not certain tho...
 
normally bad cv joints make noise or more noise on turns. a constant noise if more likely a wheel bearing. jack up the car and try to shake the wheel... look for play
 
Originally Posted By: dsmith41
Transaxle. Okay thanks!

Does the transmission fluid lubricate the transaxle as well?

How can you tell if your CV joints are shot? My girlfriend's 01 Impala has a loud humming noise you can hear in the front end. I was thinking it was just oddly worn tires but I'm starting to question it.

The sound gets louder the faster you go but after everything is warmed up and you have been driving a while, it is not quite as loud. You can still hear it but its quieter. Also, when driving at highway speeds, if you turn slightly, the sound gets quieter as well.

I was thinking tires, possibly a bad wheel bearing, CV joints maybe? I don't know.


Bad CV joints usually click when turning a corner. A speed dependent sound would steer me toward wheel bearings.
 
Just did a Tercel with separate diff fluid.2.2 pints ATF in the differential.Quite a few Toyota FWD use separate fluid for the differential,usually ATF.
 
A FWD car does not need a 90 degree change in the power flow.
They use helical final drive gears, not hypoid. This is more efficient, and a good thing. It is also less brutal to the lube.

Any tears in the C/V joint boots means get new ones. After 2 weeks being open, count them as being gone. Replacement axles with 2 new joints are surprisingly cheap, and are a highly recommended way to go. And it's easier for the average guy to do!
The quick test for C/V joint is to drive slowly in tight circles both ways. Listen for clicks. But check the boots first.
 
The 1992 and earlier SAAB 900, Dodge Intrepid, and 1999-2006 VW Passat were FWD, but had longitudinal engines. The final gear would be seperate, and be filled with a fluid different from ATF.

Also, some old Subaru cars were built like that.
 
+1 on the Intrepid/300M/etc having a servicable final drive unit and used GL5. For older Camry, Corolla and Tercel models had it filled with ATF.

Old Acura 2.5TL and 3.5RLs had a longitudinally mounted engine and has a final drive unit as well. I forget what fluid goes in it.
 
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