Hi all, Tom sent me a message saying he believes the 700R4- 4 speed is the automatic transmission to which I alluded. Roger.
You are obviously going to have internal wear from age on the selector forks but I suspect most of the problems are to do with wear in the linkages and the shifter itself
Mechanically the trans is identical to one that came behind a V6 .There is no difference in the T700 hard parts , regardless of what vehicle it came from.
popping out of second is a sign your OD unit is on its way out. soon you will see that when you are in reverse it will start slipping. My 86 is in dire need of an OD rebuild.Not a Complaint nor a Recommendation - Just Information from a User of 4+3
I've been driving my 86 with the 4+3 as a daily driver for 3 years now (it has 86k miles). I actually think having 2 sets of 4 gears (1 set for performance and set 2 for better economy(OD)) is kinda nice. OD engages automatically when using light throttle pressures in 2nd, 3rd and 4th, as long as the engine temp is 120 degrees or greater. You can also force shifting in and out of OD with the button. I generally use the clutch when I shift intentionally in or out of OD. It is just a whole lot smoother that way and easier on the OD unit I think. I like to shift, so I don't mind this.
I cannot complain about the automatic shifting of the OD except when it drops out of OD in 2nd gear when too much throttle is applied (intensionally or not) the car launches pretty briskly and my wife gets pissed at me....LOL. She hates speed! I try not to do that when she is in the car. It can also happen in 3rd or 4th gears when you apply a little too much throttle (say on a hill and you want to accelerate a little).
I have no apparent mechanical issues with my OD unit, but I think my 4 speed gear box needs some work. It will pop out of 2nd when compression breaking in 2nd gear. If I avoid down shifting to brake in 2nd I have no big issues with it. It also seems there is drive line play in my unit when you go off the throttle at low speeds (say idling through the neighborhood at 10-15 mph). I have no way of knowing if the play is in the OD or in the gear box.
Don't be fooled into thinking you are going to have 7 gears. It's not like driving a truck with a gear splitter at all. The reason I say this is the ratios the designers have chosen. The ratio of 2nd gear with OD engaged is very close to 3rd gear W/O OD. The same is true for 3rd with OD and 4th W/O OD. Those ratios are very close also.
If all the 4+3 shifters feel the same as mine, then this is an area where GM does not score well with this design. You won't be speed shifting this guy. It is less than smooth in transition between gears. It does not grind or anything. It just feels rough as you slide it from gear to gear (both directions).
Maybe this will help somewhat in understanding how the DNE 4+3 feels/drives for those who have not driven it. Hopefully so!
Thanks for the reply. I'm going to change my 4 speed gear oil to Royal Purple and see if anything changes before I do anything else.
Dealers:
