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Results from switching to Dexron VI


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I have a 4T65E in a 13yo chevy minivan, and the 4T80E in my '96 Deville. I pumped out the old original fluid about a year or 2 ago from both and filled each with ~12 quarts of Dexron VI. The chevy added about 20k, and my caddy added about 1k miles.

I noticed on both, under hard acceleration, and under load (carrying passengers), or a mild incline, when the car shifts at some point, a faint chirp can be heard.

Has anyone else experienced this? I know both cars enough that i can hear and feel when the car is going to shift, so i ease up on the accelerator at that point, wait for the shift, then resume acceleration. When i drive with that technique, i don't get the chirp. I am hopeing it is the trans breaking in with the new fluid. Both drive and shift smooth, and no trans issues at all.

I recall the Caddy had 111,000 and the chevy had about 115,000 when the original fluid was changed. Both never had any work, or were ever used for towing, or driven in mountain areas, and neither ever overheated the trans. Both had very little debree in the pan when i cleaned it out. Also filters were both replaced along with the gasket. Fluid levels are on the line when hot and in neutral.

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What does the chirp sound like? Are you sure that it's coming from the transmission but not from, say, a belt slipping on the alternator due to RPM change, or something touching the cradle or exhaust?

I would NOT worry about Dexron VI in the transmission itself. But a chirp is a chirp, and I would definitly find it.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I've done a swap-out to Dexron VI on my '04 Bravada (Oldsmobile) using GM Dexron VI and haven't had any issues (with chirping); I know, just one vehicle, but thought I'd at least give one experience. I would definitely follow Cadillac Jim's advice and troubleshoot the problem (looking at any and all other areas).

Chuck

'17 XT5, '04 Bravada........but still lusting for that '69 Z-28

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I switched my 1997 ETC with 4T80E to Dexron VI and the main difference was a dramatic improvement in cold shifting.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Better cold shifting because Dexron VI spec calls for lower viscosity fluid.

I don't know what could be causing the noise, never heard of that before. Make sure the fluid is at the proper level at normal operating temps and on a level surface. Normal operating temps are 180-200 degF. Many times anomalies can be traced to improper fluid levels, too much or not enough. Never add anything but ATF to the transmisson, never use gimmick additives. You say you pumped out the fluids, does that mean you did not change filters?

Edited by Z15
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Dexron VI is about the same viscositiy as Dexron III - in a warm transmission. The better cold shifting comes from the better control of viscosity with temperature of Dexron VI.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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From GM info

We believe in delivering the best possible transmission in the world. This means keeping up on all the latest technologies and constantly striving to improve all of our product offerings. The new Dexron 6 transmission fluid allows us to deliver a transmission that lasts longer, performs better and at the same time gets better gas mileage. The viscosity of Dexron 6 drops from 36 to 30 on cold starts and a little when warmed up as well. All while delivering better shifting and better protection during hot operation.

Bottom line is longer clutch life, quicker shifts, improved fuel economy and more HP put to the ground.

Nonetheles, its lower viscosity.

Edited by Z15
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Better cold shifting because Dexron VI spec calls for lower viscosity fluid.

I don't know what could be causing the noise, never heard of that before. Make sure the fluid is at the proper level at normal operating temps and on a level surface. Normal operating temps are 180-200 degF. Many times anomalies can be traced to improper fluid levels, too much or not enough. Never add anything but ATF to the transmisson, never use gimmick additives. You say you pumped out the fluids, does that mean you did not change filters?

I did change the filters on both. I pumped the fluid out of the radiator line while idling the car in neutral. - i understand this was the Best method for getting the most old fluid out. The fluid that came out was mostly clean, and didn't smell burnt.

That is correct never add anything to trans fluid. imo, a transmission is the most complex, and most sensitive componant of the car. Not as neglacted as the brake fluid, but trans fluid is probably the most tampered with fluid. I only switched because GM documentation recommended it at the next change interval

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You did a good thing by going to Dexron VI. Get a "mechanic's ear" and find the chirp.

Here's one on Amazon for $30:

http://www.amazon.com/Steelman-97220-EngineEAR-Diagnostic-Listening/dp/B00396FBRY

It uses a wire from the mike to the unit with the earbuds. You can use a better headset if you like. Better units, that use RF link from the microphone instead of a wire, etc. are pricier.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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