M998 not shifting out of 1st gear

[captkennyboy]

hello all my 1988 M998 was just delivered from iron planet and it will not shift out of 1st gear. Any idea before i take it to the trans shop

thanks

 

[gcbennet]

I had the same problem except mine was stuck in 3rd gear. I would suggest dropping the pan and looking for a layer of sludge that may be the remains of the other gears, as was my case. If it looks ok I'd try flushing, new filter, and maybe even switching to a high quality synthetic.