dunn378

when i'm driving about 40mph or above usually on the highway it feels like my trans downshifts to the next lowest gear if i take my foot off the gas. it feels like the car is engine braking. i don't know if this is normal but it dosen't feel like it. i don't think it matters if the car is cold or hot. can anyone tell me if this is a trans problem or if it's normal. i think i'm going to flush the trans and see if it corrects the problem. please let me know what u guys think!!! thanks in advance.

p.s. i own a 91 ls4

Lvangundy

YES~

Finallly someone who is experiencing the same thing. I've been meaning to post about this and what I think the problem is so here we go..

My guess is that the RPM's are dropping enough so that the torque convertor engages (or disengages?) When they drop below 2000RPM, or in this range the TC locks up or whatever it does.

The problem I have and what you mentioned is that this complicates freeway acceleration because my TC always does that engage/disengage thing and when I push the gas the car doesnt actually acelerate for about an entire second or more. The RPMS stay at the TC lockup spot then slowly move out of that range then to a normal acceleration RPM level. After they move up, they move down about 100-200RPM.

I'm not giving you the best description, but I know what you're talking about. One thing that helped with this problem was to get the TPS (throttle position sensor) replaced and or adjusted. The TPS keeps the engine RPMS at a certain level and can come out of adjustment overtime. I know after 2 months of getting mine replaced it doesn't feel the same as before.

How many miles are on your car? The fluid flush is a good idea, (ALWAYS USE TOYOTA TYPE-IV FLUID! - NO DEXRON) but I noticed the car 'feels' different only for a day or so, then the fluid thins out. I have 150,000 miles on my car with original tranny and engine. My conclusion is it's either the torque converter, and or the TPS sensor. Other possible causes may be the throttle body (needs cleaning past the butterfly valve thing) or the actual transmission.

I searched just a second ago online looking for 'trque converter engagement' and a site came up mentioning dirty or a worn out MAF (mass airflow meter) caused frequent TC lockups.

502husla

i know exactly what you are talking about and after replacing; after having the tps replaced and the trnsmission flushed; after a couple of days it continued to do the same thing, gave me a damn headache especially as i tried to jump into traffic on the highway somtimes. after all that and a couple more things i took it to a performance shop(actually a BMW hps) and had them take a look, come to find out........fuel injectors needed replacing. That was back in august and i haven't had any problems since then.

Lvangundy

Mabe the answers to our problem!

dunn378

i'm going to try the flush and readjusting the tps first and i'll let you guys know what happens after i drive it for a couple of days. by the way my car 212,000 miles on it!!