number44

I recently purchased a 1997 C5 6 speed with 41,000 miles on it. The shifting was rather sticky and substandard. I changed the trans fluid, it looked terrible. I used Valvoline synthetic ATF as the replacement trans fluid. The shifting improved dramatically, Then changed it again after 300 miles. The shifting improved but it's nowhere close to the " Hot Knife Through Butter"
Not satisfied with the results of the fluid change but happy my reverse lights worked now. Reading up on this "Shitty Shifting" issue it's recommended to use AC Delco Synchromesh Transmission Fluid 32oz Quart 88900333. This ATF is allegedly hard to find, And it is.... I found pricing from $33 per quart to $18 per quart on the net. I called my local NAPA store in Naperville IL and yeah we have it. Ok how much... $8.80 per quart. I told him to put 4 quarts aside and was there in minutes. So to bottom line this information, USE THE AC DELCO SYNCHROMESH 88900333 That's your GENIE IN A BOTTLE.

While pumping the Synchromesh into the trans you can see shiny suspended particles in the dark gold fluid. No other fluid has this additive.

I can certainly tell the difference with the correct trans fluid. Easer shifting cold or hot, less gear noise... Its like a a refined transmission.

Pounder

depending on the year you should not use synthetic !!! pre 2001 !!

number44

I disagree with the (QUOTE) The AC Delco Synchromesh is a synthetic blend. The bottle says so. So how can and blend be OK and a full synthetic bad?

number44

I just purchased the remaining stock of AC Delco Synchromesh at my Napa store. They said when it's gone it's gone for good. WTF

1blkc4

I use just cheapo dex 3 at walmart

Sam Handwich

And I use costly AmsOil tranny-fanny.
To each his own,

leadfoot4

Because the earlier C-5s had paper blocker rings in their transmissions, and they're not compatible with syn gear oil.

number44

"I spoke with the T-56 expert at Tremec. He said that the Mobil 1 Synthetic ATF is an excellent choice for the T-56, PROVIDED that the T-56 is a 1997 model or newer.

DO NOT run the synthetic ATF in the pre-1997 T-56 units. It will destroy the paper on the blocker rings. And do not run it in a manual trans with brass blocker rings either, because it will ruin those also.

Tremec changed the blocker rings to the carbon fiber type for the 1997 model year and synthetic ATF will not degrade these.

number44

"I spoke with the T-56 expert at Tremec. He said that the Mobil 1 Synthetic ATF is an excellent choice for the T-56, PROVIDED that the T-56 is a 1997 model or newer.

DO NOT run the synthetic ATF in the pre-1997 T-56 units. It will destroy the paper on the blocker rings. And do not run it in a manual trans with brass blocker rings either, because it will ruin those also.

Tremec changed the blocker rings to the carbon fiber type for the 1997 model year and synthetic ATF will not degrade these.

I asked about the GM SynchroMesh and he said it was good, but not quite as good as the Mobil 1 Synthetic ATF. The SynchroMesh fluid comes in the Tremec 3550.

He said you should have no problems running the Mobil 1 Synthetic ATF in the T-56.

Notice how I keep saying "Mobil 1 Synthetic ATF". He said stay away from the other aftermarket racing type synthetics, as they have extra additives that can degrade components.