Transmission issue?

[Go-Mez]

I picked up another Revo (used) and have been breaking it down to clean it up & replace some parts. I have run into a problem with the transmission, i think. I removed the engine and cleaned up the chassis, but i did not remove the tranny or drivelines. now that i've got this beast back together, it fires up and runs, but the front and rear wheels will only rotate opposite of eachother; the front wheels roll backward and the rear wheels roll forward.

I have no idea what I may have done to cause this. I ran the truck before the rebuild and it didn't have this issue.

I would love some input/suggestons by all of you with more experience than me, which is probably all of you.

Cheers!

[Double G]

One of the diffs is in upside down.

[cadmanslayer46]

Diffs are stamped "Revo Up", goes towards chassis.......

[fallonguy]

What I do it mark the top of the diff. with a white paint marker so I can see the top when I put them back in.

[Go-Mez]

Thanks for the replies... i've been absent in the hobby for a while...

I got the beast up and running this weekend and was very pleased with it.

I appreciate the help.