1990 700R4 front pump rotor surface wear?

[Burb restorer]

Greetings square body owners! Here is an interesting find. I am rebuilding a 1990 700R4 transmission and I found some front pump gear wear on one of the pump halves. If you drag your fingernail across it, you can barely feel it. I know there are re-conditioned pumps out there BUT is there a way to carefully re-condition this one? What does a transmission builder do if he runs across this and the transmission was working, only slipping in 3rd and 4th-that was due to burned clutches. I can NOT find any information other than "Carefully inspect the rotor, vanes and rotor surfaces". Can the surface actually be re-surfaced like a flywheel or cylinder head? Many thanks and keep those square bodies rolling!!

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[bucket]

Everytime I've had a trans at my rebuilder, they have replaced the pump when wear was found.

 

[JoeR Jr]

I'd replace that pump. It's got too much wear for me. It's more than just a scuff.
Joe

 

[Turbo4whl]

Back in the day when I worked in the machine shop, I would resurface the inner pump half in our large 4 jaw chuck lathe. Used the lathe's live center support on the converter support and cut a few thousands off the surface. The outer half of the pump was even harder to resurface as you need to cut the exact same amount off the recessed rotor area and the large outer surface area. We usually just replaced them.

To answer your question about the pump flow and whether or not to replace the whole pump, it would be better if the rotor and vanes were all back in the same as removed. If reinstalled where the vanes and rotor are facing different sides then the wear on the parts do not match any more. This will cause more loss of fluid flow and could have less pressure.

I should tell you the pumps I resurfaced were for large Allison transmissions, my time for repair could be under the cost for the large pump half's.

 

[Matt69olds]

Replace the pump. If you can’t polish out the imperfections out with a stone the wear is too bad to even consider to be reused

 

[Burb restorer]

MANY thanks to ALL for the quick replies, I am off to find a suitable replacement pump!

 

[Octane]

Never go cheap on a trans.Replace now instead of going into it later.

 

[HotRodPC]

Junk got caught up in the vanes and scored the pump. If you can feel your drag though it, I'd replace it. It will affect pump pressure. If it were gear type pump like a Th350 or Th400 I'd carry on, but not a Vane pump.

 

[Burb restorer]

Thanks HotRodPC. I am looking into replacements tomorrow. THANKS again!

 

[mmerlinn]

Your pump is junk. I scrap better looking ones than that one.