How screwed is my 4T60-E?

[Chris88CL]

Im trying to determine how much time I have left with my current transmission. The car is a 95 Beretta Z26 originally a 3100/4T60-E combo but now a 3400/3500 and 4T60-E combo. The transmission was replaced in the summer with one from a 90,000 mile 97 Grand Am (came free when I bought the car). I was too lazy to swap out the speedo gear so my speedo is off slightly, but thats not the biggest issue. There were a few other small issues since the donor tranny was OBDII but I swapped over all sensors and everything plugged in fine.

When Im accelerating from a stop fairly quickly the tranny almost makes a grinding noise before it upshifts. Its not QUITE grinding, but close. Sounds really wierd. Its not a steady noise though, it goes in and out. Its like GRR....GRRR....GRRR...GRRR. Probably not noticeable to the passengers but sounds slightly off to me.

The next issue is when Im going about 20-40mph and put the pedal to the floor. Instead of downshifting and catching a gear like it should, it downshifts and catches neutral and redlines. Lol. Its almost like its trying to kick down 2 gears, but there isnt anything there. It doesnt do this all the time. I can kick it down one gear at about half throttle just fine and everything works great aside from the noises mentioned above. Its just when I REALLY nail it.

I've got the body side mounts to weld in for a 5 speed swap (92+ mounts) but its too cold to pull a transmission at the yard right now so I'd like to hold off as long as possible for the swap.

Anything I can do short term aside from driving like an old lady? How long do you figure I have? Anything I can replace fairly easily to fix my problem(s)?

[IsaacHayes]

For your downshift problem, when driving 40mph and under keep it in D not OD. That will force the trans to shift down from 3rd, to 2nd, then to 1st.

When in OD at those speeds, it goes from 4th/3rd directly to 1st. When it works, it is awesome, but sometimes the motor is to fast/the trans is too slow and it will get stuck in neutral. Mine did that a few times, and even finally went into gear and screeched the tires leaving a black mark when I was going 35mph! So I only drive in D at those speeds for downshifts and no problems.

I have added the gm seal conditioner, and that made the trans run a lot better, so maybe I don't have that problem anymore? But I'll continue to drive in D and not OD. I beat on my 200,000 mile engine/trans everyday, and it runs great aside from that quirk.
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As far as your first problem, that sounds bad, but not sure what it is.

[tractorman]

I don't know what your grrr...grrr...grrr noise is, but my '94 Corsica has done exactly the same thing for years now. It started at around 100K miles... it's now pushing 150K and runs/sounds exactly the same.

About your downshifting issue- my corsica has always done that... at least since it had 80k miles when I met my wife. My solution: I don't slam the throttle down hard between 20 and 40 mph.

I think your transmission has lotsa life left in it if you'll quit dumbassin' around. Heh.

[Chris88CL]

Hmm I'm pretty sure I always have it in D? I'll double check next time Im in the car.

[IsaacHayes]

There is L, D, and (D). You want the one right after L.

That 35mph downshift is so fun though.

[Z3R0]

Weird yall are talkin about this because today i was goin about 35 runnig late and was accelerating to the speed limit and floored it. I expected that it would go in 2nd but it went all the wat into first. I thought to myself 'I wasn't going that slow'. I actually scared me because im so used to it going into 2nd when i accelerate at that spot.

[3400-95-Modified]

grrr grrr grrr is usually a TCC valve or shift valve sticking... Stock valve body valves have a high tendency to side load and then score the valve itself and stop working. They are aluminum valves in an aluminum valve body so the get kinda rough sometimes. The newer replacement valves I got for my valve body were all hard coated or had Teflon rings to seal. This prevents wear and tear on them and stops them from side loading. So it sounds like your VB is on its way out. This would also explain your missing gear effect, it may shift down too quickly and get there before the valve body has a chance to respond and get it into first or second and it just hits neutral.

OBDI to OBDII tranny doesn't make a difference, I'm running my OBDI trans on the OBDII ECM... Only thing I had to swap was the gear range switch since it plugged in differently. Other than that I know for a fact that all solenoids are the same inside the trans and the speed sensor is the same, Minus yes the higher tooth count for 97 that you grabbed... I'll have to check but if that is a 31 tooth reluctor then that may be causing your missed gear too... I would have to do the math because I'm not totally sure on that one.

[Rhedalert]

fluid level is ok?

[Chris88CL]

Yeah fluid level is fine. Thats the first thing I checked.