I know that might sound like I'm just shitty at building transmissions but I have reverse and I read that it takes more pressure to activate reverse than drive but I don't know if I believe it. I was testing it on the lift and when I first put it in drive I heard it try to activate and it spun the tires for a split second but after that it just dipped in rpm and didn't spin the tires at all. if anyone has had a similar experience I would love to hear how you fixed it thank you. any help would be greatly appreciated. I forgot to mention it is a 700r4 1986.

 

I don't have an answer for your problem, but I applaud you for diving in, getting your hands dirty, and trying to learn and do something for yourself. I'm sure you will get some great advice on this forum.

 

Does the Vehicle move under it's own power in any Forward Transmission Range (3rd, 2nd, 1st) ?

It moves in Reverse?

Does it hold in the Park Position?

 

Is the fluid full?

 

By rebuild what do you mean? What was replaced? Did you bench test the pump with the input and reverse drum assembled? Most likely the sealing rings on the input drum or valve body issue or pump is shot, could be anything. I have fully rebuilt 2 4l60/700r4s and one 4l60e and never have had an issue. You cannot rush this type of job, it must be perfect. The 86 700r4 needs to be scrapped and you need to source an 89+ 700, Sorry to be the bearer of bad news but you will have to pull it and take it apart again and transplant all your parts into a newer trans.

 

yes the car moves under its own weight in reverse and holds park but it does not have any forward gear but when I first put it in gear the tires moved a little but then lost all power

 

by rebuild I mean I was driving one day and the spray gear in the back of the trans blew up completely but didn't hurt the case but while I was in there I put in new clutches and steels but other than that everything is as it was the job was not rushed and I did test the pump and I vacuum tested and air tested through the entire build

 

yes the fluid is full

 

Sprag might be backwards

 

The early 700 r4s can be updated easily.

 

Line Pressure readings are need next for further Diagnosis.

The Forward Clutch is not Holding (Low Pressure and/ or burn Clutches).