Would a bad front cat cause trans slipping

[TSR1967]

Hello,

Been reading here for a few years since I picked up my 2000 4Runner SR5.
My truck has 153k miles, I received all the previous owners service records when I purchased it and up until now it has run perfectly.

A few weeks ago I got the P0420 and seemingly at the same time the transmission has felt like it's been slipping. It only does it from a dead stop and when I brought it to a trans place that I trust they could not recreate it.
Fluid is perfect, no smell, no discoloration etc.

I dropped it off today to my regular mechanic to have denso front and rear 02's put in. I asked him to check the both cats to see if they were an issue and it turns out the front one does need to be replaced.

Due to the amount of rust around both the front and especially rear 02 he isn't comfortable that he can get the job done in a reasonable amount of time and he is completely backed up as it is. He knows someone who can do custom exhaust work on the rear 02 if needed (it looks like where the 02 sits is crumbling, not just the nuts but where it sits)

So, my dilemma is, do I potentially have a transmission issue on top of the cats or what is the likelihood that what I am perceiving to be slipping is actually from the front cat causing hesitation?

It also seems that it might be easier to replace the rear cat as well depending on the answer to the previous question. If the other exhaust guy is going to charge $$$ to fix the mounting spot on the rear one I might as well just get it replaced and know exactly what the cost would be.

I was going to have him clean the maf and throttle body as well but I want to see what the opinions are on what is above before I spend any more $$.

Help :lmao:

 

[BrianSD_42]

I dropped it off today to my regular mechanic to have denso front and rear 02's put in. I asked him to check the both cats to see if they were an issue and it turns out the front one does need to be replaced.

Dude I'm not sure if its a New Jersey thing or what but you do need serious help.

Please add some details here because what I read is that you took your Truck into a shop to get your O2 sensors changed (preventatively?) and asked the mechanic to check the CAT as well.

He then came back and said yep well the CAT is bad also, that will be $1500+ for a single new CAT. ?????

* Was this a Toyota shop?
* Did you see the code?


[edited , toned down warning]


BTW here is a good website for ordering real Toyota parts at a discount. All local shops, if they even use Toyota parts will charge MSRP but if you order over the web from AZ or TX you will get the discount and pay no taxes on part.

http://parts.camelbacktoyota.com/partlocator/index.cfm?

These things are expensive :naughty:

 

[BrianSD_42]

something like this ...

 

[TSR1967]

Dude I'm not sure if its a New Jersey thing or what but you do need serious help.

Please add some details here because what I read is that you took your Truck into a shop to get your O2 sensors changed (preventatively?) and asked the mechanic to check the CAT as well.

He then came back and said yep well the CAT is bad also, that will be $1500+ for a single new CAT. ?????

* Was this a Toyota shop?
* Did you see the code?


I think you were just RIPPED OFF (strong possibility) or its about to happen.



BTW here is a good website for ordering real Toyota parts at a discount. All local shops, if they even use Toyota parts will charge MSRP but if you order over the web from AZ or TX you will get the discount and pay no taxes on part.

http://parts.camelbacktoyota.com/partlocator/index.cfm?

These things are expensive :naughty:

Thanks for the parts link, where did I say it was going to cost $1,500?
I brought it in for preventative and to see if the 02 would fix the p0420, which I mentioned it had.
Yes I saw the code, at pep boys, on the innova that I bought, and from the mechanic that I use, who is not a thief.

Where are you coming up with these #'s and assumptions?

Any input on the "slipping" issue and if it could be cat related or not?
Did you actually read what I wrote before coming to these conclusions? :lmao:

And no way would I be buying the stock replacement cats, and have been looking to see who makes the best stuff for the price as a replacement.

Thanks

 

[BrianSD_42]

Ok yes I was skimming pretty fast

I guess what I don't understand is that when you dropped it off with new O2 parts (I assume were the right ones because this truck is really picky and aftermarket O2s are a no-go) you mentioned you would like to know if the cats are bad.

So even though the mechanic has not yet replaced the O2 sensors and the truck still has the original code issue ... he diagnosed (without removing anything) that YES the CAT (which is a $1500 part) is bad. It doesn't sound right to me.

Those used cats (sounds like you have 2) are worth some money. Even if you replace them with cheaper aftermarket parts you face a risk, depending on the brand, of throwing engine codes. Do a search on this forum, see my signature for help, about aftermarket CATs and our 4Runners. You will see plenty of threads and maybe some recommended brands.

And the mechanic will actually get some $$$ back on the side market for selling your (broken or fine) CATs because of the precious metals inside - even honest mechanics will do this because well .. why not.

* I would just want to be really really sure before letting him pull your CATs.
* My truck (and many others) have over 200,000 miles on original Toyota CATs.
* It is not a part that needs to be preventatively replaced.


So my suggestion would be to tell him to replace the 02 sensors first, see if it fixes the code and then get a second opinion on the CATs.


To your question about TRANS slipping I don't even see how that could be remotely possible but I'll wait for someone else to chime in.

:fishing:

 

[TSR1967]

I have known the guy for years and he is not looking to replace parts for no reason. I actually bring him parts because I do not expect a mechanic to shop the internet for the best prices out there.
I got the Denso's on Amazon that were recommended for the front and rear 02.
I can get my old cats back from him if I wanted to as well.

I was not looking to get the cat replaced, the original idea was to do the 02's to see if that would fix the p0420 but the front cat tested bad and the rear is rusted to shit.

He said it's possible that if the cat is backed up and not flowing properly that it could potentially screw with the trans shift points...hence my original question on if anyone has had a similar experience.

 

[LittleCaesar]

I am guessing you have had a couple of problems with it and they all need to be addressed.

Get the new cat. It happens that they fail. Replace it and the 02 sensors if the latter is original, A/F sensor if it is Cali spec.

Ask the mechanic to drain your ATF. Refill with new (probably 4qts or more). If the trans fluid is dirty, it may shift better with the new in it. However, be prepared that there may be damaged that cannot be cheaply rectified.

 

[BrianSD_42]

I can get my old cats back from him if I wanted to as well.

Did he already replace the front CAT? I assume based on your posts that as of now nothing has been repaired/replaced.

I guess I just didn't understand how he tested the cats beyond reading the code. That code is known to be caused by O2 sensors as well as bad CATs. So my point was that if it is possible your O2 sensors are throwing the code don't preventatively replaced the CAT until after the O2 sensors.

BUT there could be something I'm missing here. Is there another way to test the CAT still on the truck besides the code?


It sounds like you are pretty on it. Sorry if I seemed too skeptical of your mechanic.

 

[TSR1967]

He did not replace the front cat yet, I am still trying to figure out which brand to go with, Cali emissions, in NJ. 6cyl.
What a pita that has been looking up reviews on that, etc.

Trans fluid is clean and good, I already had that checked out.

All good on the mechanic comment, I am a mechanical moron, not an idiot lol

 

[Kraze]

Here's my 2 cents about the cat. The previous owner of my 4runner replaced the rear cat with a magnaflow cat at about 214k miles. He is an ASE master tech, so I would hope he knows what he's doing as far as that goes. No codes, and no problem passing smog, even here in California with the aftermarket cat. And the Magnaflow cats are way cheaper than the OEM ones, and from what he says, they make one for the front as well.

Take it for what it's worth though. I try to go OEM on everything, but I would not shell out $1,200 for a cat before trying the cheaper Magnaflow version first, knowing what I know now.

 

[TSR1967]

Here's my 2 cents about the cat. The previous owner of my 4runner replaced the rear cat with a magnaflow cat at about 214k miles. He is an ASE master tech, so I would hope he knows what he's doing as far as that goes. No codes, and no problem passing smog, even here in California with the aftermarket cat. And the Magnaflow cats are way cheaper than the OEM ones, and from what he says, they make one for the front as well.

Take it for what it's worth though. I try to go OEM on everything, but I would not shell out $1,200 for a cat before trying the cheaper Magnaflow version first, knowing what I know now.

Thank you

 

[WillK]

How was the cat tested that it failed? Was it tested using the gauge check? Could the bad 02 sensor be causing the cat to test bad?
Do you smell the strong sulfur smell? (usually the sign of a bad cat)

Bad O2 sensors can cause issues with performance, but so will a cat.
A bad O2 could/usually causes the fuel system to go into an open loop, which would cause the car to run rich- how's your gas mileage?
It would also make the it run sluggish, but again- so would a bad cat...

I'd start with the cheaper things, O2 and go from there.

Not sure if that's helpful, but that't what I would suggest...

 

[TSR1967]

How was the cat tested that it failed? Was it tested using the gauge check? Could the bad 02 sensor be causing the cat to test bad?
Do you smell the strong sulfur smell? (usually the sign of a bad cat)

Bad O2 sensors can cause issues with performance, but so will a cat.
A bad O2 could/usually causes the fuel system to go into an open loop, which would cause the car to run rich- how's your gas mileage?
It would also make the it run sluggish, but again- so would a bad cat...

I'd start with the cheaper things, O2 and go from there.

Not sure if that's helpful, but that't what I would suggest...

That was the original plan before he got the result on the front cat, not sure which diagnostic he did exactly (again, I trust him) it wasn't just the p0420, he singled out the front one. The reason for doing the rear is that the sensor mounting point is shot, looks like it's almost rusting through on the spot where it sits. He doesn't want to screw with that one because it looks like it might crumble if he does. He knows a guy who might be able to weld on a new piece but that will not be cheap, and it's not that local to me. For my $, if am am going to do it, I would just get the rear magnaflow as well for $256 and cross my fingers that it would help the whole "slipping thing"
It would basically be about a $700 gamble with 2 cats and having the sensors installed.
I had aadco sways put on it, has new tires, new bilsteins, etc. etc. so I am not anxious to just sell it and having the service records since new the previous owner did a lot of the work already.
Fun decision.

 

[Millerad1651]

The trans slipping, does it just take a while to get going, or is there a clunk noise when coming to a stop/taking off? If it's the latter, it may be your driveshaft. Has it ever been greased? There are 8 or so zerk fittings that require greasing periodically. I had those symptoms, greased it up, and been fine ever since.

 

[TSR1967]

The trans slipping, does it just take a while to get going, or is there a clunk noise when coming to a stop/taking off? If it's the latter, it may be your driveshaft. Has it ever been greased? There are 8 or so zerk fittings that require greasing periodically. I had those symptoms, greased it up, and been fine ever since.

I did that last year and it fixed that issue. It's more of a revving to 2k or a little over before it kicks in, from a dead stop. It doesn't do it all the time either, or at higher speeds.

 

[rideexileex]

I did that last year and it fixed that issue. It's more of a revving to 2k or a little over before it kicks in, from a dead stop. It doesn't do it all the time either, or at higher speeds.

A slip would be evident if the RPM's bounce a bit as the torque converter tries to catch and fails.

 

[TSR1967]

I wound up picking up front and rear magnaflow cats for $589 total, and had my mechanic clean the maf, throttle body, and install the 2 new 02 sensors + both cats.
He charged me $240

I brought it to my transmission guy and he scanned it, "it thinks it's in a different gear than it's actually in while in 2 and D"
He kept it for a week, checked all the fuses first to make sure it wasn't something simple. Even though nothing was coming up with any code or screwy with anything electrical he thought it was the a & b shift solenoids.
He was correct. Total cost $375

It better behave for awhile.
Thank god I have good honest mechanics.