2000 Impala LS transmission issues

[Tzu]

We have a 2000 Impala LS, 213,000 miles and about every six months it has an episode where the transmission will feel like it has a shift kit on it. Meaning it shifts harder (but firmer) thought each gear when normally it shifts smoothly. After I went into a store to buy coffee, 5 minutes later driving away it worked fine. Fluid level is right on "full" when hot, and it isn't burnt or discolored. A/T fluid and filter changed 35,000 miles ago. Could this be an electrical issue? Secondly, when it goes into OD, it will more than half the time go in with a "surging" motion. The tachometer goes up and down about 400 rpm when doing so. Doesn't seem to hurt anything, but does gets annoying at times. I believe it is the 4T65E tranny. Thanks guys

 

[NHGUY]

I'm really stretching here,but I wonder how good the charging system or battery is? Lower voltages and computers dont work too well,higher (normal) voltages and things work better.

 

[Tzu]

The battery is decent. It's a 5 year old Walmart one. Lights seems to be bright. I will check the voltage tomorrow and see how much it's putting out when it's running. Thanks for the quick reply.
Originally Posted By: NHGUY
I'm really stretching here,but I wonder how good the charging system or battery is? Lower voltages and computers dont work too well,higher (normal) voltages and things work better.

 

[71Chevyguy]

Transmission temperature can be an issue that would cause the tranny to shift very firm. Improper fluid will also do that as well. Never use any of the Lucas products or any other "thickeners" in the transmission because that will be the end result in an electronically controlled transmission. I would actually suggest you check the coolant and see if there are deposits in the radiator possibly not allowing the tranny cooler to do it's job. I have seen a problem like that in a car with your tranny and a thorough coolant flush took care of the problem. Also had another one do that and it eventually needed a radiator replacement because the flush was not enough to clean out the tranny cooler. Also you may look into replacing the thermostat if that has not been replaced recently. You may simply be running too hot, not hot enough to trip any warning lights but too warm for the tranny. Make sure your cooling fans are working as well.

 

[yonyon]

Replace the pressure control solenoid and pray?

 

[eljefino]

Originally Posted By: yonyon
Replace the pressure control solenoid and pray?


Yup this and you might as well do the others while you're in there.

If it's heat related you could also stick a big huge cooler on and cross your fingers.

Apparently there's a kit you monkey with with the pan off and you don't have to dig too dip, that band-aids the issue as well somehow.

 

[oggb]

Didn't a lot of GM vehicles from this era have this same problem? My S-10 did. Fairly certain it was the pressure control solenoid that had caused it.

 

[mattd]

sounds like the converter is going in and out of lockup in O/D. could be solenoid issue, or failing converter.

 

[Trav]

Your lucky it went this far on that unhardened forth gear input shaft.
Don't mess with or put $$ in a 4t65e at this mileage just get a rebuilt with the upgraded 2004 and up shaft and other weak parts.