Transmission ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

FB85C10 · 07-06-2016, 01:37 PM

can this be repaired, its a TH350C transmission:

GRADYS Performance · 07-06-2016, 01:46 PM

No, Because the dowel pin hole has been broken off the case, the engine to transmission alignment cannot be maintained even if welded back together. The case should be replaced.

**Desert1957** · 07-06-2016, 09:18 PM

350 Turbos should still not be that hard to find. Have some one swap the guts over to a new case. Or do it yourself, it is not that difficult.

Desert

andrewmp6 · 07-08-2016, 04:54 AM

There is metal stitching but would cost more then a new trans would.I'd look for a new trans like you have or maybe upgrade to a 700r4.

minitrail · 07-08-2016, 06:00 AM

Just out of curiosity how did that happen? Looks like a recent (clean) break.

I agree look for a replacement.

**hatzie** · 07-08-2016, 09:28 AM

It's broken around the dowel pin. That's what aligns the center of the mainshaft. It can never be repaired such that the mainshaft alignment will be correct.
I assume the TH350 is otherwise almost new...
If you can find a worn out TH350C core you could swap the internals over. That's only worth it if the core is free, or darn close to free, and the one you have only has a few hundred miles on it.

I think I'd go the upgrade route with a decent TH700R4.

SkinnyG · 07-08-2016, 11:51 AM

It ~could~ be repaired, but you'd want to jig it up to make sure that the crank centerline and input centerline are perfect. This may require disassembling the case anyway, or just gamble and try your best to get it lined up in the truck.

I say see if a good welder near you can do it. TIG is best, but a spool gun could work.

Put it this way:

Right now it's messed.

If you are successful in welding it, at worst it will be less messed.

If you can't fix it, well - it was broken anyway.

You really don't have anything to lose by trying.

07-06-2016, 01:37 PM	#1
FB85C10 Registered User Join Date: Jan 2013 Location: NJ Posts: 58	Transmission ? can this be repaired, its a TH350C transmission:

07-06-2016, 01:46 PM	#2
GRADYS Performance Registered User Join Date: Dec 2013 Location: Columbus, Oh Posts: 366	Re: Transmission ? No, Because the dowel pin hole has been broken off the case, the engine to transmission alignment cannot be maintained even if welded back together. The case should be replaced.

07-06-2016, 09:18 PM	#3
Desert1957 Registered User Join Date: Apr 2009 Location: New Freedom Pa. Posts: 1,335	Re: Transmission ? 350 Turbos should still not be that hard to find. Have some one swap the guts over to a new case. Or do it yourself, it is not that difficult. Desert

07-08-2016, 04:54 AM	#4
andrewmp6 Registered User Join Date: Jan 2009 Location: Louisville,Ky Posts: 5,811	Re: Transmission ? There is metal stitching but would cost more then a new trans would.I'd look for a new trans like you have or maybe upgrade to a 700r4.

07-08-2016, 06:00 AM	#5
minitrail Registered User Join Date: Jun 2016 Location: Stamford, CT Posts: 52	Re: Transmission ? Just out of curiosity how did that happen? Looks like a recent (clean) break. I agree look for a replacement.

07-08-2016, 09:28 AM	#6
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,916	Re: Transmission ? It's broken around the dowel pin. That's what aligns the center of the mainshaft. It can never be repaired such that the mainshaft alignment will be correct. I assume the TH350 is otherwise almost new... If you can find a worn out TH350C core you could swap the internals over. That's only worth it if the core is free, or darn close to free, and the one you have only has a few hundred miles on it. I think I'd go the upgrade route with a decent TH700R4. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

07-08-2016, 11:51 AM	#7
SkinnyG Registered User Join Date: Feb 2012 Location: Beautiful BC, Canada, eh?! Posts: 2,189	Re: Transmission ? It ~could~ be repaired, but you'd want to jig it up to make sure that the crank centerline and input centerline are perfect. This may require disassembling the case anyway, or just gamble and try your best to get it lined up in the truck. I say see if a good welder near you can do it. TIG is best, but a spool gun could work. Put it this way: Right now it's messed. If you are successful in welding it, at worst it will be less messed. If you can't fix it, well - it was broken anyway. You really don't have anything to lose by trying. __________________ 1961 Apache: "Grabber Orange" Shortboxed, pancake, step-notch, air-ride, boosted-LS 1977 Silverado: Shortboxed & dropped, potato-potato V8 Pontiac Firefly (Chevy Sprint): The ultimate engine swap: 5.7L in a 1.0L bag Lotus Super 7 Replica: Scratch-built street-legal rollerskate



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