I am rebuilding my trans and have purchased a 13 vane replacement pump. I noticed in some rebuild instructions that the stock pumps came in three different widths. From what I can tell reading the instructions you need to have a pump assembly that is .001 smaller than the pocket they fit into on the pump housing. So doing some measuring I find the replacement 13 vane pump is .002 larger than my housing depth they fit into. I didn't see an option to buy different size pumps? So will this interferrance fit cause problems?

 

variable sized pump parts were available from dealer / delco last I looked, but wait until you get an experienced auto-trans. guy in here to answer.

 

Do not buy the 13 vane setup. There is nothing to gain with the 13 vane setup here. Get the replacement 10 vane rotor and slide, and check the clearances with a depth micrometer. The rotor should be .002" - .003" and the slide the same, but it can have a looser clearance, .003" - .004". Anything tighter than .002" will tend to gall that part.

 

I already have the 13 vane pump, so you are saying the pump can be .002 wider than the pocket in the housing and it will still work O.K.?

 

Any clearance less than .002", and you will gall the pump housing. That is why I suggest the rotor should be .002" - .003" and the slide the same.

 

Actually the pump and slide are the same width, the problem is they both are wider than the pocket they sit in by .002 so when I bolt the two halves of the pump housing together there will be a interferance fit. I will have to mount it on the convertor and see if the pump will turn.
I guess if I want to buy a specific pump gear width I need to visit a trans shop or the dealer? After market pump gears must all be the same width?

 

If it is sitting up out of the housing by .002", you will have to take it to machine shop and have him solve this. You could flat sand it, but that would take forever. You cannot have less than .002" clearance.