94 Tranny Slipping after Engine swap

I just swapped out engines in a 94 C1500 2WD. The tranny ran great before the engine went bad. I pulled the bad engine then the truck sat for about 8 months before I finally got around to installing the new one. Now the tranny seems to want to slip when giving it gas. Ive checked and recheck the fluid and Ive gotten it up to the full mark, it got a little better each time I added more fluid but id still not 100 percent. Have I over looked something?? Thanks for any help.

Has the transmission ever been serviced?
Filter and fluid change?
MT

Never been serviced that I know of, only a weekend driven truck and always ran great before engine swap. I suppose servicing it should be the first thing I attemp, it just always ran so good that I was curious if anyone else has ever had a similar problem.

If your adding fluid this is probably not the problem. Did you check the tv cable adjustment (kickdown cable). I know that will make a transmission slip a lot if its not adjusted right.

Serviced tranny and runs great once again.

Serviced tranny and runs great once again.

Sounds good. Glad all is well. And thanks for posting back how it went..
MT