1979 gmc jimmy tranny problem

[exodus138]

my trans was slipping getting into first for the past week... i checked fluid level and it was full. now it doesnt shift into first at all. do i have to have it rebuilt or could it be excessive slack on the detent cable?

[The dream]

Start with the simple stuff.

[exodus138]

has anyone used lucas transmission fix? if so does it work well?

[fitz]

 I know a few people who used the Lucus "mechanic in a can" just to buy some time in winter beaters. I don't think it's intended to be a permanent repair. I think the key to using that stuff successfully is to add it to the trans at the first sign of trouble, not waiting to the tranny is junk.
 I think at this point your looking at a rebuild.

[VileZambonie]

What transmission do you have? Does it work in manual low?

[exodus138]

350 transmission it gets in first fine... but thats all wont shift up i give it gas the motor revs but no shifting. changed the filter and fluid.. found small slivers of metal in it. think its toast?