Quick question.
I had my 4t65e rebuilt last month. First issue that arose was the valve body began sticking, causing line pressure issues and the car to slam into gear when selecting R and D.
After I got that fixed I sprung a transmission fluid leak. I changed My dipstick tube since it was broken, started leaking even worse.
Took it back to the shop that rebuilt it and after a couple of days they tell me my reverse servo cover is cracked and leaking while in reverse.
Would this issue be caused by the car slamming into gear under high line pressure or an incorrect install of the servo cover?
I realize this would be covered under warranty but I'm curious as to what would crack the servo cover like that.

If this is still under warranty, stop touching it and demand they fix it, or you will file a complaint with the BBB and your states attorney general office.

The shop told me I could replace the dipstick tube and it wouldn't void the warranty. The car is also been in the shop since Monday awaiting a new servo cover and he has mentioned nothing about charging me to fix it.

Ok.
A leaking R cover shouldn't cause hard engagement, if anything, it will bleed the pressure off and cause softer shifts. But that depends on how big the leak is.

It almost sounds like the pressure solenoid(EPC) is allowing too much fluid to the pump. I suspect someone F'd the rebuild.

I'll wait for someone else to come along and answer my question.

Statements like that will just ward others off because of the attitude.

After re-reading your initial question about what would cause the cover like that to crack?
Seriously, improper removal and or installation.

Slamming gears did not crack the servo cap. How it cracked would be a guess.

Due to the fact someone 'rebuilt' the transmission, one can only correctly assume the cover was damaged during repair.
End of story.

I figured that would be the other cause. I got upset because you were coming across as directly negative and didn't read the part where I said the hard shifting had been fixed.

Other than the cap the transmission shifts beautifully, so it was a good rebuild.