IBrakeForCats

Hi all, new here to the forum. Had a Chevy G20 van for years that ran great and was easy to work on, recently obtained a '93 Suburban K1500 4wd and while it runs like a top, I've found that when shifted into 3rd or Drive it lurches me forward, hard as it shifts into gear. I can alleviate this by quickly throwing the shifter into 2nd, and shifting into Drive after 2000 rpm and it will shift smoothly through all the gears.

At every red light I have to repeat the process; drop into 2nd, accelerate to 2000rpm and then shift up and everything is dandy. Shifting into 1st, 2nd, and reverse from park are all smooth as well as 2low and 4high and back. I have replaced some common items as I do all my old but new to me rigs.

New spark plugs, wires, cleaned distro cap and rotor.

New TPS

New EGR valve and EGR control solenoid

Lubed rear slip yoke with Dex III compatible ATF and topped up transfer case. Was about 0.5qt low and yoke was wet with nice red ATF.

Fuel filter replaced.

Inspected motor and tranny mounts with my girlfriend in the driver seat and there was hardly any perceptible play under load in drive or reverse.

I think that's all that's relevant thus far.
Tranny was 0.5qt low, topped up with lubegaard shudder fixx (same used in my rovers) and ATF, but was nice ruby red from the start.

I'm looking toward the 1-2 actuator but going to drop the pan anyway to see what's up. Previous owner may have installed a shift kit but tbh I'm not sure what all that implies. It's confusing which gears are affected because if I accelerate in 1st then shift up to 2nd it slams into gear as well with the same veracity.

Would rather have some ideas and opinions before I drop the pan and am very open to suggestions. She runs great when I treat her like a "manual" but I know she's capable of more.

I will take a video in the morning and hopefully post the follow-up and solution I found as this problem seems prevalent amongst the many years of 4l60e and Chevy Suburban/related models and almost nobody has ever actually videod what is happening and shown the result after they fixed and and how they did so.

Glad to be a part of this forum, and let me know how I can be more specific until I get some video posted.

Thanks,

Cats