Jolly

Hi guys, I took this thing out of storage. Hooked up the battery and took it out for the first time in about a year. On the highway I lit it up and for what I remember as the first time ever it bounced the rev limiter from 2-3 shift while in D. I repeated the take off in OD and of course it shifted fine. Went back to D and took off and it repeated the same rev limiter bounce.

Now I have driven the car since new in 2000 and I don't remember this ever happening. So am I loosing my mind, car needs to relearn something (I doubt this) or what else you guys think? Fluid level is normal.

Car's stock except for what's mentioned in the sig.

Jolly

goatfishbird

I have nothing to offer as far as advice goes, but my car does this on the 1st to 2nd shift sometimes. Interested to hear an answer to this.

thunderstruck507

iTrader: (18)

Try overfilling the trans just a little and see if it helps. Not much, maybe start with 1/4 qt, maybe 1/2.

mrvedit

Yes, that has helped others. The stock car-sized trans pan is a bit shallow and heavy acceleration can cause fluid starvation.

However, this may be an early warning that the 3-4 clutch is starting to slip. In [D3] during the 2-3 shift, the 4L60E both engages the 3-4 clutch -AND- engages the overrun clutch. Engaging the overrun clutch takes a little bit of fluid pressure from the 3-4 clutch, allowing it to slip a bit.
In [D4] (OD), the overrun clutch is not engaged and a bit more fluid pressure is available for the 3-4 clutch. This is consistent with your symptoms.

For this reason, it is recommended that you use [D4] (OD) at the track and not [D3]. We have had several threads on this topic:

https://ls1tech.com/forums/automatic...do-you-do.html (See my post #13)

https://ls1tech.com/forums/automatic...-drive-od.html

A more technical thread:

https://ls1tech.com/forums/automatic...ift-flare.html

Jolly

mrvedit;
Thanks for the information. That clears it up some. I remember years ago heated discussion on which provided better performance either OD or D. My personal preference was D and at that time most everyone else in the discussion went with D. I saw no evidence of Tranny issues from the discussion so that's where I left it. Obviously that was a long time ago in a different forum and things have changed.

The car recently had a tranny flush so I suspect the fluid level is not as before and I will add a little to the level and see if that makes any difference. Its right at the line so maybe a little could help. Its not worth the effort to fight to use D for launches if it will possibly cause tranny issues.

Again Thanks.

thunderstruck507

iTrader: (18)

I was unaware of that, I thought putting it in 3 was preferred.

Guess I will start using OD.

mrvedit

Racing it in [OD] puts more strain on the forward sprag since the overrun clutches are not engaged.
Racing it in [D3] may cause the 3-4 clutch to slip during the 2-3 shift because the overrun clutches are engaging at the same time.

You have to pick your poison.

As I mention in those threads, the Sonnax HD 2-3 shift valve is highly recommended because it keeps the overrun clutches engaged in [D3]. Sponsor Jake Performance even said "The Sonnax piece is an almost mandatory upgrade IMO."

The 700R4 kept the overrun clutches engaged for all gears in [D3] and as a result some builders thought this was also true in the 4L60E and the mistake in the ATSG manual doesn't help. (Guess the ATSG staff didn't notice the change.)

thunderstruck507

iTrader: (18)

Thanks for the info. I cannot remember if we used that piece in my build or not but I think so.

mrvedit

Its easy to tell - put your shifter in [D3] and slow down from a speed high enough to be in 3rd gear. With that valve forcing the overrun clutches on, you will feel the 3-2 downshift as being quite abrupt. Same with the 2-1.

01ssreda4

iTrader: (96)

My builder says race in D, and I do. Have been for years...no trans issues to date.

gtfodave

could aslo be a bad solenoid

Jolly

MRVEDIT, thanks again.
I see what it takes to do the sonnax part and I read all the other info and it certainly is the correct thing to do. Might be beyond my capabilities at the moment. Although I find myself a competent mechanic I tend to shy away from anything tranny related. Unless there is a step by step write up on this I don't think its a good plan for me to shart tearing into the tranny.

Again thanks for all the help.

Jolly,

mrvedit

Jolly, I could write up the exact steps to remove/replace the valve body (VB), or even help you over the phone.
However, I am concerned that your 3-4 clutch is starting to slip and the effort might not buy you much, other than learning.
If you did decide to give it a try, I would highly suggest installing the Transgo HD2 shift kit at the same time as removing the VB is the biggest part of the effort. That will likely extend the life of your trans.

Someone posted the HD2 instructions here:
https://ls1tech.com/forums/automatic...questions.html

Besires the Sonnax 2-3 shift valve, I would suggest having these parts handy:
1. New Transgo Separator Plate ($25)
2. New Separator Plate gaskets (included in HD2 kit)
3. Torlon check ***** (Sonnax part # 10000-08)
Partly in case you lose a check ball; but these are preferred over steel ones.
4. Bottle of Vaseline or TransGel
5. Pan gasket; probably new filter and 5Q fluid

You only need 13mm, 10mm and 8mm sockets, a small screwdriver and needlenose pliers.