95 tranny problems

I'm new to the forum, so bear with me. I have a 95 Blazer with a 4.3 W, at, 4x4. The problem is when I put it into OD or D I don't have anything. I can start out in 1, shift to 2, and at about 35mph, shift into D, and at about 45mph, then into OD. If I try to give it to much go pedal while in D or OD though it slips. What do you guy's think is wrong? Is it something I can repair? The tranny is a remanufactured GM with about 38k on it. Any help would be appreciated.

Shouldn't it have a warranty?

Well, that's a long story. My brother-in-law worked for a shop in Ca. that he had problems with. So he opened up his own shop. I can't find my reciept, and I have since moved to WA.

How's the fluid level?

Good, I changed the filter yesterday.

Do you check the fluid level when the truck is running right and after you go through every gear on the coloumn and back up to park.

Yes.

Welp, time to go and take it to a tranny shop.

That's what I was afraid of. Good thing it's a spare vehicle. Guess it's time to sell it after I get it fixed.

PS. Thanks for your input LT.

is your SES light on?

no.

I would first go to Autozone and have them check the codes.

Not all faults bring up a check engine light.