Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

They replaced the differential. Now the handling stinks and there's a new noise

2003 Matrix XR, 89K, well maintained by old owner, just about to become mine.
Took it to old owner’s mechanic for pre-sale checkup. He said humming noise was rear differential and replaced it.

Now it pulls to the right when driving, to the left when braking (also throbs), and generally just feels like total crap to drive. There’s also a noise that I hear as sort of a …rough grinding/roaring sound? Seems to be from the back.

Details: the hum increased in pitch as wheel speed went up. Nothing else changed it - not going from dirt to pavement, drive to neutral, uphill to down, straight to cornering. Otherwise, everything felt fine - handled really nicely, that’s why I wanted to buy it.

When I picked it up from the shop after the differential implant I drove it about a mile, flipped out at the way it felt, and took it right back; it was near closing time. Kid put it up on the lift, looked and said it was a front wheel bearing and to bring it back next morning. This morning the still-owner picked it up, test drove it and said “Yep, feels all loosey-goosey,” brought it in to the shop, and different guy says “it’s the alignment, bring it in tomorrow.”

Alignment? Wheel bearing? Why all of a sudden? Maybe the differential is bad or not installed properly? Why am I the only one thinking this?

Also, they lost one of the springs to the bit at the front where the exhaust joins on to the engine so there’s a big loud exhaust noise, which they didn’t notice when they test drove it. Also, the older guys are all on vacation and there’s only a bunch of teenagers working…

Don’t drive this vehicle anymore. This sounds like a case of getting the wrong gear ratio in the rear, it’s not matching the front differential gear ratio. This will tear up your transmission if you drive it very far.

Also, have you put any money down yet? I’d back out of the deal until/unless the car is back in shape 100%.

You took it to the old owner’s mechanic-and-also-brother-in-law?

They lost the spring off the exhaust flex-joint and didn’t replace it?

Run away from this deal. Far away. There’s something seriously wrong with the vehicle and something smells really fishy here. Who knows what else they’re covering up…or what other butcher-work the current owner’s “mechanic” has done to it.

The old owner is a friend and a good guy and eating all of the bills until it works again – he’s getting hosed as much as I am. The car was fine and we were both happy about the deal until his mechanic (the old guy in the shop, not any of the young guys actually here this week) said “that hum is a differential in the process of going; you should fix it before you sell it.”

What I don’t get is why I’m hearing “bearing” and “alignment” instead of “gee, maybe we didn’t put the new diff in right” …

The pulling to one side, then the ‘throbbing’ and pulling to the other sounds like a brake caliper is partially seized up.

At this point unless they can make the car perfect, and soon, I would just walk away from the deal and find another one.

When something new appears right after maintenance, you always go back to what you just did. Thats a primary rule in maintenance. In this case, I think it got the wrong rear gears. Its possible that they just forgot to put gear lube in the new differential or they somehow messed up the axle bearings putting the axles back in, or damaged the rear brakes, but I’m still thinking its the gear ratios.

Clear up something though, you referenced the sound coming from the rear, this is an AWD Matrix, right?

Apologies to your friend. But I’m still queezy about the shop. A shop that would leave an exhaust flex-joint half unattached raises red flags with me. And clearly someone didn’t do the rear end right.

Perhaps your friend needs a new mechanic.

Yep, this is an AWD, which is partly why I’m worried - if something is off in the back end, it’ll eventually trash the front/transmission too, right, since everything’s linked?

This is one of two shops in a small town; some people swear by guy # 1 and swear at guy # 2, some vice versa. Some figure that everyone makes mistakes now and then and go to whoever has time first. The owner is a 1, I’m a 2 by habit, but we’re each more of a type 3 attitude.

Is a rear diff a straightforward sort of thing? Or is it one of those complex, ticklish jobs with lots of nooks and crannies for things to go wrong in? I’m really getting tired of having a bunch of guys look at me (middle aged female) like I’m somehow odd for suggesting that Something Happened and the new problems are Not Just A Coincidence.

I appreciate the feedback, everyone. Thanks.

Skip this vehicle if you can.

The only cars with solid design in AWD are Subaru and Audi. Everything else has after the design lets figure out how to add/monkey a derivative of AWD in. The results typically are expensive problems for the next owner.

The rear differential is a pretty straight forward job. Which differential was replaced, I have been assuming the rear one because of your description of the noise. Toyota does have a long and good track record with 4wd and AWD.

the worst thing you can do is sell a car to a friend. He is trying to break this rule; let it(the car) go.

My vote is to back clean away from this vehicle. There are too many question marks about why so many major things going wrong at 89k miles (allegedly) along with the people doing the actual repairs; or parts flinging as it may be.

If it’s a headache now just think what it will be like when your name is on the title.