Another 4L60e question, 2-1 downshift thud

[jmvar]

Hello, here goes another 4L60e thread.

This is on a 2014 Chevrolet express awd with 130,000 miles on it. I just bought this van so I don't know if it has ever had a drain and fill. I checked the fluid level and it looks good.

The tranny shifts nicely through the gears but there is a thud I can hear and feel when it downshifts from 2 to 1 as I slow down.

I checked the u-joints by grabing both the front and rear driveshafts and shaking them and found no slop.

I also looked at the motor mounts and they look to be in good shape visually. Don't know how else to check them.

I am going to do a drain and fill with new filter.

Is there anything I can check while I am in there?

Thank you

 

[clinebarger]

I've seen/experienced this from Geartrian slack/slop from worn out parts......Was this a commercial vehicle?

 

[jmvar]

I've seen/experienced this from Geartrian slack/slop from worn out parts......Was this a commercial vehicle?

No this is a passenger van that appears to have been well taken care of looking at the condition.

I just dug through the carfax and it was dealer serviced it's entire life. I don't see a transmission service but I will call the dealer today to ask.

 

[Kira]

. Don't know how else to check them.

Vehicle on ramps / Engine running / You go under
Trustworthy buddy / Foot firmly on brakes / N to D then to R
Check for slop in the mounts as the engine torques this way and that

 

[MolaKule]

...I am going to do a drain and fill with new filter.

Is there anything I can check while I am in there?

Thank you

I would try that first and see if there is any improvement. You may also need more than one D&F if the fluid is in poor condition.

The dealer may also have kept to the "Lifetime" fluid myth and it may not have ever been changed. Drain the ATF into a clean pan and check color. A fluid sample taken mid-stream and sent in for analysis may also reveal some issues. A particulate count is recommended but only if you ask for it.

However, Carfax and other sources are rarely accurate with respect to service history, as are dealer's info. Service receipts should be kept in the glove compartment; at least that's where I keep mine if I need to review what was done when. I have seen dealers remove any customer history documents when trading in a vehicle.

@Kira above also has some suggested drive-train checks that may reveal some defects.

 

[jmvar]

Vehicle on ramps / Engine running / You go under
Trustworthy buddy / Foot firmly on brakes / N to D then to R
Check for slop in the mounts as the engine torques this way and that

I owe you a beer.

Put it on ramps and my wife shifted back and forth.

Front diff mount is toast and that thing was all over the place when the tranny was being shifted.

98.6% sure that is my thump. I will report back once I get that changed out.

Thanks!

 

[Kira]

You just made my day!
Now, when I go downtown to see the Liberty's Tickertape Parade, I'll be in a "helpful reveler" frame of mind.

 

[jmvar]

You just made my day!
Now, when I go downtown to see the Liberty's Tickertape Parade, I'll be in a "helpful reveler" frame of mind.

Well deserved.

This is part of this ongoing discussion with the dealer I bought the van from in this link.

I asked them to ship me all the oarts to fix this.

This is what the diff is doing when shifting from P to N to R to D: