Transmission Slipping (?)

[300zx Enthusiast]

Recently I just got 300 up and running after replacing the engine. The new engine has only 40k miles, with brand new style injectors and has ran perfect since it was put in. However, recently I've noticed my car will sometimes fail to build or "grab" power when im driving, especially in lower rpms. This typically happens when I'm in drive. I can rev the car in neutral or park and never have any problems but once I get down the road coming from a stop light its almost as if the car doesn't wanna get up and go, it hesitates. This leads me to believing my transmission maybe sipping or going out. The trans does have around 170k miles, and is an automatic so I planned on swapping it soon. The hesitation usually occurs before the car is warmed completely up, but can still happen after its at operation temps, its just much less common.

Im gonna change the fluids in my trans and drive it a little to try and get a more narrow idea of what it could be. In the meantime, what do you all think it may be? Any idea can be helpful. Thanks.

[Ace2cool]

Real talk, it's going out. Easiest and cheapest option is a new trans. Even if you have it rebuilt, $1200-$2000, it's still not going to be 100%. I did it in the N/A, and it worked for a few months and couple thousand miles, but then it lost overdrive again.

[DCaff300ZX]

^^^^This, the AT's for the Z32 are notorious for not lasting long. Probably the biggest reason for MT swaps- not much reason to repeat by replacing the AT when a MT swap is about the same price, if more hassle unless done by a Z specialist. My NA cost about $2,200, but that was purchasing almost everything needed including manual transmission, new shifter, new trans shift linkages, p.plate, throwout system and clutch.