Need Help! 4t60-e

[kverskvfd]

Anyone who can help me diagnose this problem will be greatly appreciated. Here is what I have:

1999 Pontiac Grand Prix
3100SFI w/145,000mi
4T60-E M13

Ok, here is my problem, when I make a hard left the transmission will go into a neutral like state, rev to about ~4k RPM and then shift harshly, this only started about 4 weeks ago but has been getting progressively worse as time passes. The fluid was changed at 125,000mi and filled with Mobil 1 Synthetic with Lucas trans additive. Please if you have any information email me at Charlie@kvfd.com or give me a call at 865-293-9564. Any pertaining information is welcomed.

Sincerely,

Charlie Buffalo

[bszopi]

I'd check your fluid level. And maybe even add a little extra. My tranny (4T60E) has a slow leak, and when it starts slipping on left turns I know its time to fill the fluid back up.

[kverskvfd]

Yeah, I did notice that the fluid was like 1/2 quart low so I topped it off, even with full fluid it will still slip, could there be air trapped somewhere that it shouldn't be?

[White93z34]

some people have issues with the trans when showing full falling out of gear, it is my understanding that overfilling it by up to a quart can help this issue.

[sharkey]

in the 80s gm released a bullitin recomending dealers to overfill the tranny as much as 2 liters. this was designed to put the planetaries in a bath of oil, but it also did cure the falling out of gear while going around the corner.

try that, if it still does it, you have internal issues.

[kverskvfd]

thanks for the fast replies, overfilling by a quart did solve the problem and yes i do have a small leak around the gasket so i will have to replace that this weekend. Anyways thanks for the help.

Charlie Buffalo

[pontiac3100]

so if i put in a quart it actully helps my tranny??
i've always heard or read that it was bad.
not questioning you here just wanna make sure....

i'm pretty sure if it was over filled to much it whould come out of the vent/overflow? tube.

[sharkey]

that was stated in a bullitin from gm. it takes most transmissions a lot of fluid before they puke out the breather. in the 4t60e there is only a couple of inches of oil in the pan when its running, and the breather is way up on top of the tranny, so your not gonna puke oil out.

at my shop we commonly overfill transmission 1/2 to 1l after overhaul. there are several reasons to do this
-when overhauled it can take a while before you get all the air out of the cooler and fluid into all the crevices of the tranny and it could end up on the low side after its released to the customer.
-if the tranny was to develop a small leak there is a better chance of it getting noticed before the trany is slipping because its low on oil
-we live close to the longest uphill climb in the world, the coquahalla highway, well over an hour of uphill driving at 110km/h (70mph). this is a lot of strain on a tranny, and with the oil sloshed to the back of the pan the entire time there is a chance it could suck air, but with it overfull it lessens the chance.
-

[pontiac3100]

hey i like that!

hey i'm not highjacking.
but when i start my car up then put her in drive right away she does'nt go in.
i would have to put her in park or reverse then drive in order for her to move.

other then that she's fine.
and the cooler helps alot.

[gpse3400]

I was wondering if you changed the filter along with the fluid. I' ve never had a problem with the trans going out of gear in turns since my old Cutlass of 10 years ago... Did a fluid and filter change on the and it never left gear again...Even if I'm 3/4 of a quart low I wont go out of gear as long as my filter is good..

FYI if you over a 4L60, 4L60-E you will loose fluid. I think all you need is a quart over to do it, drive down the expresswway and your spraying.

[sharkey]

i gotta disagree with that. ive seen 4l60/4l60e's with more than 2l extra fluid in em and they arent puking. we commonly overfill them 1/2l without any issues.

[kverskvfd]

Yes, I changed both the filter, atf fluid, and pan gasket, but im starting to wonder if I may have loosened one of the three hydraulic lines that run close to the filter. . .

[pontiac3100]

umm whould putting in 1/2 l solve the issue stated above??

[gpse3400]

Yeah well i put int a quart and it came right out.. but then again I was moving at a pretty good clip...say 130? Overall I lost a 2.5 quarts when that happend plus the extra i dumped in, it all just boiled over and onto the catalyst. Whoo that woul've been a nice fire if it went on fire....

You can try overfilling it. If it doesn't work change out the filter and get a GM or a Purolator(Allomatic) filter.