4T65E Question

I hate to beat the horse again, however:

My 4T65E seems to have the classic hard 1-2 shift when running it a little high (3500-4000 RPM's). Just seems like it's slamming into gear. I have yet to duplicate in enough situations to understand what may be going on. I only decided to go off the line a little fast after driving around, so the tranny was warmed up.

Other then that, it seems to shift fine when I am accelerating it @ or under 3k.

Car has 45800 miles on it, so I figure maybe new fluid and filter may do the trick. Do any of you with TSB access know of any fixes to this issue?

Only hard thing that I know I did to the tranny ever was back in January when I was trying to slow myself down a really icy hill and idiot me shifted down into 1st from Drive when going 30.

Thanks again.

I hate to beat the horse again, however:

My 4T65E seems to have the classic hard 1-2 shift when running it a little high (3500-4000 RPM's). Just seems like it's slamming into gear. I have yet to duplicate in enough situations to understand what may be going on. I only decided to go off the line a little fast after driving around, so the tranny was warmed up.

Other then that, it seems to shift fine when I am accelerating it @ or under 3k.

Car has 45800 miles on it, so I figure maybe new fluid and filter may do the trick. Do any of you with TSB access know of any fixes to this issue?

Only hard thing that I know I did to the tranny ever was back in January when I was trying to slow myself down a really icy hill and idiot me shifted down into 1st from Drive when going 30.

Thanks again.

The 4T65E tranny has two upshift solenoids, the 1-2 and 3-4 on the valve body. Maybe the 1-2 is sticking. You don't seem to have the symptoms of a pressure control solenoid (PCS) at this time in which one of the TSBs refers to.

You could try getting the basic service on the tranny (ATF & filter) or try some "Lubegard" or "Sea Foam" additive.

If its acting up at 45K miles, it will probably evolve to something worse. A good tranny shop should be able to scan for stored DTC error codes. A lot of the tranny codes do not trigger a SES light. Better to get it checked out.



http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

It's like sometimes it will shift smooth as silk or a very slight jerk as it shifts even from 3-4.

It was just when I was running it a little hard off the line, I felt the noticable bucking feeling from 1-2 last night. Although I accelerated a little hard earlier tonight and shifted from 1-2 just fine.

I mean the weird thing is that being able to feel the car shift just happens at some times and shifts smothly with the only indication is hearing the engine drop in RPM's.

Maybe its like you said, I have a peridoicly sticking solenoid. It could possibly be in my head too. That's what my mechanic buddy keeps saying when I pepper him with little questions :iceslolan .

On the Seafoam tranny additive, do you just dump the stuff in your transmission fluid or is there a more detailed procedure involved? Also on the error codes: I just had it in the shop diagnosing my misfire.

Would a normal mechanic be able to pull up any transmission codes or is that a different software package to pull powertrain codes? It was just the cyl 3 misfire in the computer when I had it scanned last week.

Thanks again.

The Sea Foam is pour and play. A normal mechanic with the proper scanner can pull these codes although the transmission shop can probably better diagnose the problem because that is their speciality. A mechanic probably would not scan for tranny codes unless he was specifically looking to diagnose a problem.

I use Lubegard but I've heard good things about products like Sea Foam too. Its in all of the GM "W" body cars in my household. After doing a tranny service with ATF and filter, I put in the additive. Its around 10 oz and the important thing to remember is to make sure you account for it and not overfill. On a pan drop approximately 7.5 quarts of Dextron-III will be needed. Unless its my imagination, the upshifts and downshifts are a lot smoother.

I don't use any tranny additive in my son's Alero for fear of it self-destructing. :lol2: On Aleros and Grand Ams its better to leave well enough alone. If its not broken don't fix it. Good luck!


http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

That might be the way to go is to do a fluid change and additive. I mean the rough upshifts (no rough downshifts) happen so intermittently that it's just weird.

At worst case, my baby is becoming a monetary black hole I didn't foresee :).

I agree that doing a fluid and filter change and adding your additive at that time is your best bet. That way, you don't overfill, and you have some nice clean fluid in there. DO NOT do a fluid exhange, where they hook a machine up and flush out all the old fluid, as you will be visiting the trans shop if you do. Just drop the pan, change the filter, and replace what fluid was in the pan.

Don't worry, I learned from reading the posts that fluid flushes are forbidden :).

Check out this link. I installed one on the GTP well over a year ago. Makes draining the ATF a lot easier. Plus there's extra cooling and a tad bit more fluid capacity.

http://www.3800performance.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=MSP_TRANPAN&Category_Code=T&Product_Count=3

But I was looking around for a drain kit that was more reasonable in cost and of good quality for my Regal GS. They require drilling a 1/2 inch hole in the pan. Autozone had one but it looked questionable. I think it was under $10.00. Wouldn't want the drain plug to fall out.

Rich, do you know of other tranny drain kits and the cost?




http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

Okay, sounds good. The new pan is something to consider. I have yet to do anything tranny related, so I am probably going to apprentice with my mechanic buddy on this one.

I floored it today to test (so much for great gas milage I have been getting recently) it again and it shifted smooth as ever around 4k from 1-2. No felling that it just drops into gear.

This is just funny as heck that I can't reproduce this issue every time. Wonder if it's temperature related. I am starting to lean towards its a mental issue. I will try driving it like a manual (letting off gas before shift) to see if that alieviates this "symptom."