After too many hours of reading about atf and viscosity, after comparing cSt values (did you know -40C and -40F are the same temp?) and such from at least ten products, and noting a couple of warnings about the use of synthetics in old transmissions, I've decided to go with a non-synthetic dex/merc for the first few changes.

Has anyone used the mobile atf d/m to replace Dexron II? I'm considering this for next year, as it seems to be in the range of Dexron II as far as viscosity goes. I do not have actual detail pages or product data for the Dexron II specifications (though I almost did buy them) so i'm basing this comparison off of a review of dexII product info that I found online...and a suggestion from a mechanic.

Anyone upgraded their pan magnet and if so, could you point me in the right direction there...also considering a supplemental filter w/magnet.

Thanks, y'all.

I changed the trans oil, filter and gasket. It took about 5.5 maybe 6 quarts.
There was no magnet in the pan. There was a small amount of metallic grit in the pan and one very small thin flake. Fluid was still brown with a ting of red from the change I did in Sept.

I'm getting a little better pickup upon acceleration but the coast down clunk is still there. At the next change I may add the magnet. I decided to use the Mobile D/M for the high viscosity and because it is inexpensive and I'll be flushing it out before the winter.

I believe this intermittent clunk is resulting from a 2-3 accumulator malfunction but this is really just my best guess...without reading the astg manual. It seems the TransGo kit addresses the 1-2 and 1-4 accumulators.

Can someone confirm that the 2-3 accumulator for 4T60 is not part of the accumulator assembly that is accessible from the bottom pan? This info could save me from spending $60 for the manuals.

Thank you.

by the way, the torque specification for the trans oil pan is 96-120 inch lbs
After cleaning the pan and the appropriate portion of the trans with some solvent and plastic scrapper, i used a suggestd 100 inch lbs for torquing and the neoprene gasket. so far the seal has not leaked.

TSB: 08-07-30-040B. It involves adding two improved magnets.
part # 29535617.

These magnets were installed on the third fluid change from the oil pan. At the fourth change they were completely coated and looked like little donuts.

I'm at 96% new fluid in the case all Mobil D/M.

Maybe this summer I'll get back under there to reinspect the magnets.

Take some photos of the particulates on the magnets next change, & post them.
Dexron VI is the latest GM transmission fluid. Some of the features & benefits are listed below.
Transmission Fluid: Dexron VI Transmission Fluid | ACDelco
I personally would not use anything other than an approved GM fluid in my transmission.
Possibly others can advise about the accumulators on a 4T-60.
I do not have a manual for that trans. Were the accumulator bores accessible once pan was removed, got pics?