4L80E hard shift

[grasshopper]

The 4L80E in my 93 diesel is acting up on me a bit. It usually shifts very nicely, I have not had any problems with it other than a couple valves or something two years ago. Now from time to time it shifts really hard into second. It will do this for a day or so, and then the next day be totally fine. The fluid is right up, and I had it flushed and new filter put in it in the fall. Before I go to a tranny shop to get their opinion, I would like to see what you guys think it could possibly be, as I don't really have a tranny shop that I trust too much here. Thanks

[TreffertLawnWrx]

I'm goig to change the filter/fluid on mine tomorrow. I always believe dont touch anything unless it breaks, but i do have over 100K. but only about 5K plowing. Anything I should know before tomorrow? i will be using GM filter and fluid. Thanks Scott.

Sorry I wasn't able to help with your ?

[snowjoker]

Mine did the same thing a couple weeks ago. I changed the filter and it solved the problem, I changed the filter last summer, and did not have that many miles on the change.

[GLS]

Sorry, I can't really help you either. I just had a question for you guys with the 4L80E--

When I move the shifter down to second gear (as in D and OD lockout), the shift from 1 to 2 is hard. However, when in D or OD, all shifts are smooth throughout. Just wondering if there is a reason for this and if other 4L80Es do this too (mine is a 95).

[grasshopper]

OK now its really a big problem. I was driving to a conference yesterday, and noticed that overdrive is not working. It now shifts hard in every gear as well. I am guessing the tranny is in "safe mode". Does this sound like it could be a shift solenoid or whatever they are called, and possibly not a tranny rebuild? The fluid does not sound burnt and it doesn't slip in gear. Can anyone out there give me some hope that I may not need to rebuild this tranny and only have to do a minor fix? I am going to the shop on Monday to get it checked out. Even if you have to lie and tell me its a relatively cheap fix, at least it will give me a sense of hope and I won't spend my weekend worrying about how much this could cost me. Thanks:(

[grasshopper]

I had a nightmare last night about going to the tranny shop and this is how much I envisioned it costing me:eek: