My 700r4 may be FUBAR

Discussion in 'Transmissions' started by PlayingWithTBI, Feb 10, 2019.

  1. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    I bought my 88 C1500 in 2002 from a guy who managed a transmission shop. He said he rebuilt the tranny and recently put in a shift kit and a GM factory long block 5.7 (made in Mexico). Last year it started overheating so, after removing the heads I found 2 spots where it was bypassing through the head gaskets. Anyway I decided to replace the heads and started reading about how bad TBIs breathe. So, after a 46mm bored TB w/18LB spring, Edelbrock 3704 intake, Summit Racing (Trick Flow) 170cc heads, Lunati cam, headers, high flow cat and 3" exhaust to 3 chamber muffler, and a "performance" chip, I wasn't happy with the results. That's when I started doing research on tuning with TunerPro RT and, with the help from a guy on GearHeads-EFI, started tuning and data logging.

    All of a sudden my tranny started shiftin @ 5400RPM, even though I changed the weights on the governor to shift @ 5000. Then after a couple more 0-60 runs, it shifts, even at part throttle, at over 5000RPM in gears 1-2 & 2-3! Tranny fluid is bright red and smells good, TV cable is still hooked up and when I pull on it at the TB linkage it springs back in place. I ordered a governor gear, a Trans Go SK700-JR kit mainly for the TV valve and springs, OTC transmission pressure gauge set, Filter, gasket, and fluid.

    Any ideas or input?
     
    Last edited: Feb 10, 2019
  2. Schurkey

    Schurkey I'm Awesome

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    Fluid level correct?

    Drop the pan, look for debris. Pull the governor, look for damage, bad gear, sticking weights. Might as well look at the Throttle valve, assure it's not seized.

    "I" would probably try a fresh filter and fluid, before putting ANOTHER shift kit in the thing.
     
  3. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    Thanks Schurkey;
    My son is coming over tomorrow and we're gonna tear into it. Hopefully I have what we need to get it going. I'll let you know what we find...
     
  4. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    Update - we pulled the governor, all's well, put it back in. Hooked up the pressure gauge to the test port (1/8" pipe plug) above the shift linkage, started the engine. The pressure went up to ~180PSI (S/B 90 - 110 in P), didn't change when pulling on the TV cable. So we dropped the pan and valve body. Found a small "Jesus" clip in the pan but, other than that it was pretty clean. Went to pull the TV spool assembly but it was stuck all the way in. Replaced it with the spool and springs from the Trans Go kit. Unfortunately when dropping the valve body the separator plate gasket tore in two plus we can't find one of the check balls. Don't know if it was there in the 1st place. I ordered gaskets and balls. We'll put it back together next Monday.

    Have some pictures, will post them later...
     
  5. retorq

    retorq OBS Enthusiast

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    There are shift kits that will have you leave out one of the balls. Superior is one of them, I think B+M did the same on one the kits I worked with in the past. Since you're in there replacing all the balls I would look at torlon balls. They won't beat up and wedge themselves into the separator plate like the steel balls can over time.
     
  6. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    Thanks retorq for the advice. This particular missing ball is shown being there in the Trans Go kit instructions too. Where can I find these torlon balls?
     
  7. Schurkey

    Schurkey I'm Awesome

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    ^^^ What he said. I never heard of 'em.
     
  8. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    Some pics;

    The "Jesus" clip (every time you just about get it in place, it flies across the room, and you say J****!!!). No idea where it came from, probably from another job in the bay next door when it was rebuilt last time, LOL.

    IMG_0729.JPG

    The heavy cast valve body with the torn separator gasket, we were hoping it would have stayed with the separator. The TV plunger is sticking out on the bottom. It goes in and out but the TV spool is stuck.

    IMG_0732.JPG


    The old TV spool.

    IMG_0733.JPG

    Jacked up the tranny, removed the cross member support and set the tranny down on jack stand to get to the back pan bolts. Note the pressure gauge hanging towards the back out of the way. Once we get it all back together we'll check pressures again.

    IMG_0735.JPG

    Valve body mounting bolts and other stuff laid out in orientation when taken out.

    IMG_0734.JPG
     
  9. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    One more (for now);

    The missing ball goes in the socket inside the red circle.

    upload_2019-2-12_12-4-23.png
     
  10. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    Woo Hoo! We got it back together yesterday. Well, my son did most of the work, I just cleaned and ordered parts. Now it shifts better than it has in a long time. All we used out of the TransGo kit was the TV spool and spring that goes in the end of it to keep it from getting stuck again. Pulled separator plate and cleaned it up. Had some wear in the holes where the balls go but not bad enough to worry about. All of the accumulators and valves already had bigger springs than what came with the kit.

    After installation we checked the TV cable, it touches the plunger when at idle and pushes the plunger all the way in at WOT. Started it up and pressure read right at 90 PSI. When I pulled the TV cable the pressure jumped to 300 PSI then dropped to ~180.

    Here's some more pics;

    The instructions from TransGo were vague at best, you have to drop the valve body to get at the roll pin, pull it out, then you can get the TV spool out. We had to pry it out - definitely stuck.

    upload_2019-2-19_10-13-37.png


    A cheap die grinder with a 3" red scotch bright wheel, some solvent, brake cleaner, paper towels, and a blow gun makes the job cleaning everything a lot easier.

    IMG_0742.JPG

    I like to set up an old card table near the project and keep all of the parts in paper bowls labeled where they came from.

    IMG_0744.JPG

    Use Vaseline to keep the balls in place during installation.

    IMG_0747.JPG

    Torqued valve body bolts to 8 ft/lbs, spring detent to 15 ft/lbs, and pan bolts to 10 ft/lbs

    IMG_0749.JPG
     

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