1996 GMC Sierra SLE

[zoot]

I am having a problem with my '96 GMC Sierra SLE with a 5.7 L engine . The transmission works great in all forward gears but it is very erratic when put into reverse . P0306 , P0430 , P1351 and P1870 were the engine codes . Any advice or suggestions would be greatly appreciated .

 

[zoot]

By the way , I've changed the transmission filter and fluid . It had a very small amount of residue in the bottom of the pan and the fluid was still red and normal looking .

 

[crunch]

You have 3 engine running codes that need fixed.
Remember a engine has to be running good for the transmission to work good.

Define erratic in a little more detail.

How many miles on transmission?
What transmission? 4L60E or 4L80E?
Have you had it on a transmission capable scanner?
Any slipping or delay on up shifts on scanner reading?

 

[zoot]

I'll let you know later today which transmission that i have . By erratic I mean it's about a 50-50 chance that reverse will engage or not . I'm on my way back to the shop to correct the engine codes . Apparently I have a cylinder miss on bank 2 , # 6 cylinder . I understand that I need to correct the engine issues and only then start with my transmission issues . I do appreciate your counsel as I am in no way anything more than a shade tree mechanic at best . I can change parts , but I leave the diagnosis to people that actually know what they are doing . Again , whatever the outcome , thanks .

 

[zoot]

There are roughly 35,000 or so miles on the transmission . It is a 4L60-E . I'll get it scanned as soon as possible . It has shuddered before upon going up a hill , but it hasn't appeared to slip or shudder any other time and certainly hasn't since I changed the filter and fluid .

 

[zoot]

Ok , my engine is running great . The check engine light is no longer on and has stayed off . Still haven't scanned the transmission , but the problem hasn't changed at all . Still no reverse .

 

[crunch]

Scan transmission and let us know.
Is the fluid level up good when hot?