Rebuilding my TH400

Discussion in 'The "Juice Box"' started by 1969RIVI, Jun 9, 2019.

  1. Bens99gtp

    Bens99gtp Well-Known Member

    It could I guess, I think the biggest issue with swimming comes from sliding the tongue converter back too far and smooth not engaging the pump gears in the transmission enough and damaging them.

    As Larry mentioned make sure the converter slides in the pilot hole smoothly.


    I would look to make sure no burs.......put the new flex plate on. Hand test fit converter, it should slide in the pilot hole enough to actually touch the flex plate. Better to find this out without dealing with tran in there. Then on final assemble put converter in trans, make sure it's full engaged all the way. Should sit inside the bellhousing by a good amount, then push converter all the towards trans and measure gap between it and flex plate and shim if needed
     
    Last edited: Jun 10, 2019
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Yes, it didn't help. Not sure why it flexed the flexplate though unless there was some interference in the crank hole that prevented the converter pilot from going all the way in.
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    No, that flexplate is the way stock ones look. The solid ones are aftermarket, JW the wheel and the one I had on my engine from TSP. You definitely want to get the spacing right. Aim for 1/8". Take up anymore with washers.

    IMG_1255.JPG

    I'm just curious if your starter works the same with the replacement flexplate you bought.
     
    Last edited: Jun 10, 2019
  4. 1969RIVI

    1969RIVI Well-Known Member

    I sure hope so! It's a big old honking stock starter. Is anyone running a JW "The Wheel" flexplate with a stock starter? Maybe I'll call TA and ask them if it can be used with a stock starter.
     
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    They will tell you yes. You may be just fine. I ran a stock starter for awhile while I waited for the Robb Mc starter. It was just fine. It was the mini starters that kept getting hurt with the flexplate on my motor. Now that I have replaced my flexplate, I'm sure I can use anything.
     
  6. Bens99gtp

    Bens99gtp Well-Known Member

    I have a stk starter on my jw wheel, no issues what so ever. Have had a jw wheel for more than a decade now
     
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I thought I read somewhere about how the JW wheel had a problem with teeth, but I can't find the thread. I didn't have any issues using the stock starter either, but with the particular flex plate on my motor originally, the Robb Mc starter was the only mini that would last and was quiet (after using 2 shims). When I removed that flex plate and replaced it, I had to remove both those shims because the pinion was a mile away from the flex plate. There was an issue with it, and I have no idea whose make it was, but it was solid unlike the stock flex plates.

    EngFinal1R.jpg
     
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  8. 1969RIVI

    1969RIVI Well-Known Member

    So the disassembly went quite well and I have a bunch of photos and questions. First off I'll ask about this modulator on my trans it appears to be an original. It has o bolt on the end for the tranny ground strap where as the new one from the kit is much smaller and has no bolt. Where would I mount the strap now using the new modulator? I will be posting pictures and questions in sections as to not cluster up the thread.
     

    Attached Files:

  9. 1969RIVI

    1969RIVI Well-Known Member

    Here's my trans tag, it appears to be a 68? Any help decoding it? I also noticed upon disassembly that the tail shaft is from 67 and it has the smaller diameter end seal and smaller bushing. My kit I bought says it's good for th400's from 65-76 but the bushing and seal are too large
     

    Attached Files:

  10. Bens99gtp

    Bens99gtp Well-Known Member

    The 67 and earlier trans did have a small od slip yoke. I'm sure those parts can be found, I always change the housing since those slip yokes are hard to find. But that wont work for you in this case. I'm sure your local trans shop if they are worth their salt can get you the seal and bushing you need.

    Ground is ground, you can put it anywhere on the trans.
     
  11. GranSportSedan

    GranSportSedan Puppet dictator, wife has all power

    it says super turbine 400 on the tag. small output housing.. sure looks like a 67 to me. does it have the variable pitch pump assy?
     
  12. 1969RIVI

    1969RIVI Well-Known Member

    It has 68 stamped on the tag. I figured when they were building the cars for the 69 year they just used up whatever parts they had leftover from previous years? Ive read on here before that that was quite common back then. Excuse my ignorance but how would I be able to tell if it has a variable pitch pump assembly?
     
  13. Bens99gtp

    Bens99gtp Well-Known Member

    Take a picture of the shaft coming out of the pump assembly,

    I know alot of 67 bt were switch pitch that came in big cars. I dont recall them having an extra ground wire on the modulator though, they did have 2 wires going to the kick down ug
     
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  14. GranSportSedan

    GranSportSedan Puppet dictator, wife has all power

    never heard of a switch pitch 400 in anything later than a 67 in a Buick. factory most certainly would not have used extra 67 transmissions in a 68 because the kickdown and VP linkage would be totally different. carburetor would have to be a 67 as well to even make it work.
     
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  15. 1969RIVI

    1969RIVI Well-Known Member

    So it's a one wire/prong on the kick down switch, which wasn't hooked up. There's a blue and yellow set of wires with the ends missing that was attached to the frame coming from the rear of the car somewhere near the one prong switch. It's a 68 trans with a 67 tail housing in a 69 Riv with a 72 455 engine and carb. Here's the shaft coming out from the pump.
     

    Attached Files:

  16. GranSportSedan

    GranSportSedan Puppet dictator, wife has all power

    Sounds like a mixture of stuff.
     
  17. 1969RIVI

    1969RIVI Well-Known Member

    Sure is lol
     
  18. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    One way to tell a Switch Pitch from a Fixed Pitch 400 is to look at the input shaft. The stator splines on the SP are 1/2 the width of the splines on a FP transmission. 2 prongs means nothing since they used the second prong for emissions in later years (TCS)

    FPvsSPSplineComparison.jpg

    Fixed Pitch on left, Switch Pitch on right.
     
  19. 1969RIVI

    1969RIVI Well-Known Member

    Here's a pic with the clutch and pump together. Does this help identify it? Looks to me like a fixed pitch?
     

    Attached Files:

  20. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Fixed pitch.
     

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