Changing Trans Fluid

[GN2018]

In researching changing my trans fluid, I came across this video.  I was surprised at the disassembly required to do the work.  I was also impressed with the detail/professionalism that the mechanic demonstrated.  I run my truck light duty but want to maintain my vehicle so I use the severe maintenance schedule which calls for the fluid to be changed at 45K miles.  I’m at 36K and was planning on doing it at 40K.  Is all that work necessary?  I’m thinking that I’d would be possible, and sufficient to just drain and replace the fluid.  Alternatively, if I decide to go with the full service and drop the pan, who should I work with?  Since I don’t work on my truck, who would be best to go too in order to ensure the work was done at the highest level.  I’m worried that the dealer will just change the fluid and charge me a bundle as if they dropped the pan and did the full service.
 

 

[Joe Drives]

I had my 8-speed transmission serviced at the dealer at 40,000 miles. This is a transmission fluid exchange only using a Wynns flush kit P/N 10210 with new fluid P/N 88862155 per the service order. This was performed last year just shy of $300.

[newdude]

34 minutes ago, Joe Drives said:

I had my 8-speed transmission serviced at the dealer at 40,000 miles. This is a transmission fluid exchange only using a Wynns flush kit P/N 10210 with new fluid P/N 88862155 per the service order. This was performed last year just shy of $300.

 

 

Wrong fluid was used.  Take it back. 

 

88862155 is Dexron 6.  8 Speed ONLY uses Dexron HP which is GM p/n 19417577, Mobil 1 Synthetic LV ATF HP.  It is the ONLY fluid approved for the 8 speed.  

Edited April 2, 2025 by newdude

[Joe Drives]

Thanks for the fluid clarification New Dude. I am going to inquire at the dealer.

[redwngr]

And for those with 10 speeds, Dexron ULV is required. 

 

(yes -- each of the 6, 8 and 10 speed require a different fluid)

[64BAwagon]

Rockauto is the best price I have found

 

[GN2018]

So no one ever had their pan pulled and their filter replaced?  I feel like that's the best thing to do but if the exhaust does actually have to be dropped (as shown in the video) and the price is $1K versus just flushing the fluid for say $300, I guess I'm going to go with the flush.  I wouldn't mind spending the $1K, but trying to get someone competent to do the work properly would be a challenge.  I can hear the exhaust leak now.

[Transient]

On 4/2/2025 at 3:22 PM, 64BAwagon said:

Rockauto is the best price I have found

 

Agreed.  All the brick and mortar stores only have Valvoline ULV, and want $17.99/ quart in my area.  Rock Auto has AC Delco ULV for under $5/quart plus shipping. 

[64BAwagon]

My local Chevy dealer is close to that price also, all in figuring shipping from Rock. If I recall the sweet spot for the best value per qt shipped was around 8 or so. I added some on to a couple of orders until I was well stocked. 

 

[im4snow2000]

On 4/3/2025 at 9:33 PM, GN2018 said:

So no one ever had their pan pulled and their filter replaced?  I feel like that's the best thing to do but if the exhaust does actually have to be dropped (as shown in the video) and the price is $1K versus just flushing the fluid for say $300, I guess I'm going to go with the flush.  I wouldn't mind spending the $1K, but trying to get someone competent to do the work properly would be a challenge.  I can hear the exhaust leak now.

Few months back I had a private shop drop the pan and do a full service (8spd).  I have complete trust in this shop.  The manager forewarned me it was expensive, due to the time involved (as noted in the video you posted).  I spent about $690 on just the transmission service in Oct 2024.  

 

My truck's a 2021 with about 55-60k miles at the time. Note that at about 30k the above shop did a simple fluid replacement (maybe flush too, not sure) at way lower cost.  The truck is used very lightly, but I hope to keep it a while, hence my potentially excessive maintenance (and these newer transmissions scare me).

Edited April 6, 2025 by im4snow2000

[KARNUT]

I just give my experience. I’ve never done a transmission filter. I just do drain and fills. If your transmission filter is clogged the days are numbered. Keeping the fluid clean is all you need to do. I’ve never lost an automatic transmission yet. Most of my vehicles are on the high mileage side. My avalanche got its first transmission drain and fill at 167K miles 5 years ago. My odyssey at 127k. It just got another at 157K. My Ridgeline at 127k and 160K. My wife’s Genesis at 60K and 130K. No filters.

[johnnyquick]

On 4/3/2025 at 6:33 PM, GN2018 said:

So no one ever had their pan pulled and their filter replaced?  I feel like that's the best thing to do but if the exhaust does actually have to be dropped (as shown in the video) and the price is $1K versus just flushing the fluid for say $300, I guess I'm going to go with the flush.  I wouldn't mind spending the $1K, but trying to get someone competent to do the work properly would be a challenge.  I can hear the exhaust leak now.

Dealer usually charges around $400 for this and YES the exhaust needs dropped and you should get new donut gaskets just in case.

It is a ****** plus you do need to get it up to operating temp for the fill level to be proper, power brake procedure, wait again and again and again..lol

Put some Amsoil in it if you want to improve over the factory stuff, don't worry about the warrant being voided as GM will not honor jack sheet anyway no matter what.

Cheers