thunderstruck507

iTrader: (18)

The rebuild my dad and I did on the trans is about 4 years now using pretty much all the normal good stuff (Alto clutches, good steels, band, beast sunshell, trans go kit, high rpm "No Yo-yo" kit, etc). Pretty much everything short of 5 gear planetaries and I was unaware of the Sonnax 2-3 valve.

It used to only be an issue on the track which I thought was a shift point tuning issue. I recently learned racing in D or 3 instead of OD can cause the flare.

Lately though when doing some spirited driving on backroads it seems to be lagging shifting manually on the street too. I've been making sure to lift throttle until it completes the shift.

Fluid isn't burned and is clean (does look a pale pink rather than red but that could be the cheap fluid I topped it off with last time I blew a rubber line). Fluid had a full change last summer (~10k miles) with new filter.


Do you guys think the new fluid and HD valve should get it back to normal for a while or should I just go ahead and plan on pulling it for a refresh? I have a private track day coming up May4th so I would like to run that, but I'm thinking after that day (if it doesn't scatter anyway) of pulling it to go through it and replace anything that's worn and maybe get the converter freshened and restalled as a 4000.

mrvedit

The Sonnax HD 2-3 shift valve by itself will not IMO reduce your flare. However, you must remove (and mod) the valve body to install the valve, and if you then drill the 3rd apply hole a bit bigger (.093 to .125), that may reduce your flare. You might even want to install the Sonnax servo release check valve at the same time; which BTW instructs you to drill the hole to that size.
Those are all good parts to have when you eventually do rebuild the trans.

thunderstruck507

iTrader: (18)

Is the 3rd apply hole not one of the holes normally increased by installing the transgo kit? I don't recall off hand but can look for the instruction sheet online.

performabuilt

iTrader: (25)

Agreed the Sonnax valve will not solve a flare issue , Sounds like you have a 3-4 clutch excessive clearance issue ,

thunderstruck507

iTrader: (18)

Guess the clutches must just be getting worn.

It used to only do it in 3 though, would shift fine in OD. So I was under the impression this valve was to correct that issue.

Sounds like it's about due to get pulled apart for inspection and probably replace the 3-4 clutch pack at minimum. I appreciate the help guys. Just trying to get a further grasp on the finer details of a performance 4l60e. Guess 4 years of service from one getting a constant beating and a lot of track time isn't too terrible.

The car was recently on the dyno and showed no signs of trans slip, also holds fine on the street in 3rd and 4th. Just seems to be slow applying 3rd when not in OD. Shifting from 3 to OD let's it shift quickly and firmly into 4th even, it's just the 2-3 that seems a little sloppy.

I would have to look through the notes my dad and I had on how the clutch pack was set up last time, but are there any tips anyone would be willing to share on how to set up the 3-4 set next time?

mrvedit

Yes, the Transgo kit instructions has you increase that to .093. A know a bunch of performance builders go to .125. The bigger hole will give you more volume (up to a point), which can be useful if you have a minor leak in the circuit, or as suggested above, if your clutch clearance is excessive.

thunderstruck507

iTrader: (18)

Thanks again, I will do that too and maybe it will be enough to crutch me through this upcoming race.

It's not the normal type of "slip" I'm used to so much as it feels like there is a hesitation to even begin applying 3rd, then it comes on fairly strong.

But I guess one can only expect so much from a 4l60e, my dad is fairly well versed in stock rebuilds on them at his shop but mine is the first venture into making one live behind a decently high HP engine and high stall converter. All help is much appreciated.

performabuilt

iTrader: (25)

Yes the valve will help solve the issue in D3 but if its also happening in D4 then I would suspect clutch wear issue.

thunderstruck507

iTrader: (18)

Guess I was confusing in my wording...it only happens in D3 or when going from 2 to D3 manually.

Example 1: At the track I do my burnout, then put it in D3 and launch letting the trans shift itself when it gets ready to go from second to third it often kisses the rev limit before the shift completes (even though the shift point is a decent bit lower than the rev limit).

Example 2: On the street I enter a corner and I ratchet downshift off throttle from D4 to 2 before the turn to engine brake and on exit shift from manual 2 into D3, there is a slight lag then 3rd kinda comes on in a wave rather than a quick "snap". A shift from D3 to D4 is still quick and snappy.

tjwashow

iTrader: (2)

just leave it in od when your driving and not burnging out? seems like a known issue that it lags when in d3 (something about not enough line pressure, or its different in d3 compared to od)

mrvedit

Yes, unless you have the Sonnax 2-3 shift valve installed, you keep it in OD. Otherwise during the 2-3 shift both the 3-4 clutch and overrun clutch need to be engaged at the same time, robbing the 3-4 clutch of pressure.

So, I guess the answer to your original question is YES; Frank and I didn't realize you were manually shifting and/or driving in D3.

thunderstruck507

iTrader: (18)

Excellent.

I'm going to assume it wouldn't hurt to over drill the plate anyway though for a little extra security?

mrvedit

Don't go over .125.
I recently bought an "alternative" to the Sonnax servo release check valve which looks similar but uses Holley carb jets to control the flow. The idea is that installing a different jet is an easier way to tune the servo flow than redrilling/replacing the separator plate. However I haven't tried it yet.

thunderstruck507

iTrader: (18)

Got this done. Much better. Everything is nice and smooth under normal throttle and shifts are quick and slop free. The one time so far I've let it shift under WOT it was nice and firm and instant and the car just kept pulling.

I really like the noticeable downshifts when slowing down too. Thanks for the help guys.

mrvedit

Glad to hear that the Sonnax HD203 shift valve worked well for you.
Do you remember what size you drilled the 3rd feed hole in the separator plate?
Did you also drill the hole in the valve according to the instructions? What size?

Ted.

thunderstruck507

iTrader: (18)

My separator plate was already drilled to ~.110 but we opened it up to .123 (that was the closest precision bit we had to .125 without going over) as you suggested for good measure.

We followed the instructions and drilled the valve body with a 1/8" bit. Gave everything a thorough cleaning and replaced the catch screens and put everything back together with fresh fluid and new gaskets.

thunderstruck507

iTrader: (18)

I don't want to get my hopes up too high but I really hope I see a small gain in 1/4 mile MPH now that it's not banging the rev limiter and lazing it's way into 3rd.

It certainly felt a lot stronger pulling once in third too but that might have been a glitch in the butt dyno because if I understand correctly this shouldn't have had any effect on actual 3rd gear holding power, just in how it applies.

thunderstruck507

iTrader: (18)

Just want to follow up here again to say how much I love this part.

Did another WOT pull to pass a long row of slow traffic and it just about got a tire scratch hitting 3rd on street rubber. Safe to say this is a huge improvement over nosing over, hitting the rev limit for a split second, then sliding into 3rd. Might need to turn the pressure down just a hair on it now.