How do you know which type of transmission you have. I have a 91 rd 305tbi. I've read some have the 4l60 and some came with the 4l60e.

Can someone explain the difference to me and which one my car came with.

 

700R4.

JamesC

 

is it the vacuum lock up or electronic lock up ??

 

If it's stock you have the 700R4. Provided it is the automatic.

 

I think 4th gens had 4l60s in them. never heard of one in a third gen. unless its been swapped. 700r4s have a three wire,four terminal plug that is on the driver side for the converter lockup. not familiar with 4l60s

 

The 4L60E (note the E) is the electronic version of the 4L60 (note no E) transmission. The E version was never factory in our 3rd gens.

The 4L60 transmission is the same exact transmission as the 700R4.

GM changed the naming convention in 1990 or '91. As it stands the '92 3rd gen factory service manual refers to the automatic trans as the 4L60 transmission, RPO code MD8.

The reason for the naming change is to better reflect the physical attributes of the transmission.

4L60:

4 - four forward speeds
L - longitudinal layout (T for transverse, FWD)
60 - torque rating, metric, no sure of the units used

E - electronically controlled

RBob.

 

The TCC lockup is ECM controlled, so it is electronic. This is true of all of the US based 3rd gens with a TCC. Some export models had vacuum controlled and pressure switched based lockup.

RBob.

 

Going to be a good day: I learned something today that I was unaware of yesterday. I don't have a 90 shop manual but the 91 shows the 4L60.

JamesC

 

That's why I asked because I have the 91 shop manual and it says 4L60, but everyone says 700R4. How difficult is it to pull and rebuild the transmission I'm a complete noob at transmissions so if it's best left for professionals I will pay to have it done, but if a guy with some mechanical knowledge can accomplish rebuilding it then I'm all in!!