[jbroome2]

First let me start off by saying hey, you have a wonderful site with lost of great info. I have searched and cant find anything so here goes. My 4l60e has no OD or D until you put it in 1st and get going then you can put it back in OD and it does fine, you can then come to a stop take back off anything untill you go to P,N,or R. After you go into P,N, or R you have to go back to 1st until you get going once again. I have changed the input sprag, low roller clutch and the shift silenoids with no change. Thanks in advance for any help.

by the way this is a 2000 GMC Sierra.

[Crosley]

Originally Posted by jbroome2

First let me start off by saying hey, you have a wonderful site with lost of great info. I have searched and cant find anything so here goes. My 4l60e has no OD or D until you put it in 1st and get going then you can put it back in OD and it does fine, you can then come to a stop take back off anything untill you go to P,N,or R. After you go into P,N, or R you have to go back to 1st until you get going once again. I have changed the input sprag, low roller clutch and the shift silenoids with no change. Thanks in advance for any help.

by the way this is a 2000 GMC Sierra.

Please clarify an item here for me:

Do you mean the vehicle will take off from a stop with shifter in OD and the trans shifts to 2nd gear , but will not shift to 3rd gear or OD ?

OR the vehicle will not move from a stop with the shifter in OD or D ? .. You must place the shifter into 1 gear so the vehicle will move from a complete stop?

Two different causes and effect . I want to make sure I understand your problem

[jbroome2]

Once you come out of park you have to go to first gear, then once rolling you can put it in OD and it will shift on its own if you come straight out of park to OD it just sits there.

When you come to a stoplight from being in OD you dont have to do anything you can leave it in OD and it will take back off.

[Crosley]

I would be interested in what the pressure of main line is doing when the trans will not move in OD after the shifter is placed there from park.

Pressure is boosted when t he shifter is in manual 1 gear.

What is the history of the trans in the 2000 truck? Mileage? Recent repair or rebuild? Sounds like you've had the trans out and apart a couple of times

A pump with excessive clearance can actually stop pumping when a load is applied like shifting from park into gear.

There may also be a problem with the forward sprag assembly. I had a customer that claimed our sprag parts were bad that he had just purchased. The problem was he had put a new sprag against worn out sprag races and took out the new sprag.

[jbroome2]

If the sprag were bad wouldnt it do it all the time? Its just weird after it has moved in D or OD it works great. Ill have to check pressures. and as far as a history I dont know I just got the truck. Thanks for your help this has been driving me crazy.