transmission not locking into gear..HELP

[dranger21]

Well I have a 99 with the 3.0 motor and 4r44e transmission. I've now had the transmission rebuilt twice and I'm having trouble again. After replacing it once, it went out again so I had it rebuilt the second time after finding out the radiator was leaking into the tranny all along. Now for the the third time it seems to be going out again. The only reason I would know though is because I came down a steep mountain road one day and decided to shift down into first and save the brakes. When I got to the bottom I was going 45mph in 1st gear at 1000 rpm. The transmission is not locking up for some reason. I was told it could be the speed sensor but it looks to me as if the speed sensor is on the rear diff and not the tranny. I am totally frustrated and fed up with this thing and my next step is going to be selling the truck if this is another major problem. If anyone has any suggestions or ideas of what might be wrong I would really appreciate any input. Thanks in advance
This is an automatic by the way.

 

[exbass94]

How fast were you going when you shifted into 1st? If you were going too fast, you could screw up the trans. It probably has a safety feature that won't allow it to go into 1st if you're going too fast. So, you may not have been in 1st at all, even though the shifter was in 1st.

 

[dranger21]

I started out from a stop and usually do when I'm shifting into 1st..definitely no more than 10mph

 

[dranger21]

I guess I forgot to mention that I'm hearing a whining noise when I put the car in gear and drive, but not in park. The whine goes in unison with the rpm's. Could this be a bad torque converter or valve sticking in the valve body? Anyone?

 

[Viper Command]

I guess I forgot to mention that I'm hearing a whining noise when I put the car in gear and drive, but not in park. The whine goes in unison with the rpm's. Could this be a bad torque converter or valve sticking in the valve body? Anyone?

there are a few things....

Bad tc
overly cloged filter
bad pump
clogged cooler line


also the trans overheats pretty quikly(sluggish shifting, flair up)

Its pretty funny I just rebuilt and converted a 4r55e to 4wd for masterbrendon.

just rember all 4r--e are the same as an a4ld, but the valve body is diffrent.