billybatty

I have about 800 miles on a rebuilt 4l60e, which I did, fingers still crossed. Everyhting has been good this whole time except for the typical low throttle 1-2 harsh shift. Decided to get the sonnax atva for the valve body accumulator. After dropping the pan, I was a bit suprised by the amount of material on the magnet, maybe about 1/16 inch of darker goop. Has a few very fine metal particles in pan, but this could be left over from previous failure of front plant bearing. No clutch goop in bottom of pan, no bad smell to the fluid, ran the fluid thru a paint filter, and it looked pretty darn good, a couple of very fine particles. I did set my 3-4 clutches pretty tight, at .022( BW hi energy 8 frictions). So is this goop on the magnet normal break in wear or should I be worried? BTW, I do have a magnifine inline filter and the tranny filter looked clean, still tan not discolored or dark yet.

mrvedit

Let us know if the Sonnax ATVA valve makes any difference in your shifts. That looks like one of the few Sonnax parts I have never tried.

Sorry, I don't have the experience to answer your Q about the dark goop. I'm sure you aren't going to rebuild the trans due to it, so cross your fingers. My guess is that you didn't clean out the trans well enough when you rebuilt it.

IMHO .022 is a bit tight for 8 frictions. It should work fine (well even) on the track, but might wear down quite a bit in 10,000 miles. It will last longer if you installed the 5x load release springs. But I don't know all this for a fact. Again, if this isn't a DD with a lot of yearly miles, it won't matter.

Gearstar Performance

The material you found on the magnet may be normal assuming you still used your factory transmission cooler as there will had been debris left in the cooler which will only flush out over time with hot new transmission fluid. Again, assuming you are still using your factory radio cooler, I would recommend you test the amount of flow for restrictions in the cooler as follows:
The simple method is to get the trans up to operating temp, verify, by touch, that both cooler lines at the radiator are hot to the touch. Leave the hood open for 1/2 hour (not running) so that both cooler lines have cooled to the touch. Find a safe area of cooler line, where you can touch both lines, while someone starts the car. One line will heat up (almost instantly) and the other line a few seconds later. This verifies good cooler flow. If it takes more than 5 seconds for both lines to warm, there may be an restriction in the radiators trans cooler. Cooler flow volume needs to be verified. On the 4L60E, the upper cooler line is the return from the cooler this line can be removed and run a length of 5/16 cooler hose installed on the end of the cooler line which you removed, and run it to a container. While holding the hose in the container, and someone turns on the vehicle you should get one qt of fluid in 10-15 seconds. If this is not obtained, the radiator should be bypassed and a 30,000 GVW cooler should be installed

billybatty

Will let you know how much the avta works, and yes this is a DD and no I didnt reuse the boost springs, guess I'll see what happens long term, so far I like the up and down shifts, except for the jerky 1-2 at low speed, 1-2 is good if your on the gas some.

billybatty

Great advice on checking cooler flow, will do it tonite.

carlsonauto

The amount of crud you found is certainly normal. .022 is certainly a bit tight for 8 frictions but its a bit late now to change it. Thats less than .0015 of clearance per side of each friction and will cause some wear and gunk in the pan. I usually build 7 friction units and shoot for .035 -.040 clearance and have yet to have any issues at that clearance (.005-.006 per friction or .025-.003 pre side per friction) I still get some gunk in the pan at that clearance with flushing the cooler/s with a hot flush machine for however long it takes to stop getting the visible crud out of them.

Please do post the results you have with that valve.. What diameter valve did you order??

billybatty

Yes it is a tight stack, this was the recommended setup( .020 to .035) by the guy I bought the stuff from. In the interest of full disclosure this is a 2002 yukon xl family truckster so I ordered the m-k valve (.340 I think.) Will get about a month more drive time and pull the pan, check the magnet and post the condition and if the valve is making a better low throttle 1-2 shift. Thanks for the replies.

billybatty

An update for those interested. After a couple weeks w/ the new sonnax accumulator valve(with medium spring), I initially thought it improved the 1-2 low throttle shift. But on the first really warm day here, the 1-2 shift got pretty jerky/harsh again. I will say that I left my band one the loose side during the rebuild, one gold shim made it what I thought was too tight. (I know, I should have used a new pin sized properly.) So I decided to downsize the 1-2 feed hole to .076 from .082. Again I installed a gold shim, but it still seemed to tight, so removed it. So I downsized the hole, changed the sonnax accumulator valve spring to the pink spring(strongest) because the medium spring dialed down my other shifts, even for a DD. I definitely like the combo of changes, 1-2 at low throttle, even on hot days is firm but not that jerky clunky deal. And the other shifts are back where I like em with the pink spring.

billybatty

Oh yeah, on last two pan removals, had very little goop on magnet, so I'm thinking my tight 3-4 clutch setup is good to go after intial break in period.