My trans shop told me about this that if we are to put in a TH400 they have had trouble with the flywheel flexing, and the tc shaft eats into the pump, causing it to fry!!!Anybody run into this problem? I have a stock flywheel that was already balanced with the crank and H/B and he said I should get a aftermarket flywheel, if I do I would have to ripp my lower end apart to have it rebalanced!!!I dont want to do this!!

 

Sounds strange to me.

Question: Why are you going to a TH400? You have to have a bunch of power to make the switch cost-effective. If a daily driver, it doesn't make any sense at all.

Observation: Lesson 5 in Hot Rodding 101 - NEVER balance the engine with the harmonic damper and flywheel/flexplate. Doing so will cause heartburn if you ever need to replace the harmonic damper and/or flywheel/flexplate. But, you know that now.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. 2-1/2" cat-back, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 CC system w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker 2055 headers, 3" Catco cat & 3" catback, restalled TC, Spohn SFCs).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

Its called mr 700r cant have trans brake 400 can

 

So, strip reasons. Gotcha.

Perhaps Pro-built or transfixleo can shed some light on this. Or someone who has put a TH400 in their car. Mine was factory engine/flexplate/transmission, so I never had to address it as a "swap".