TH 350 bellhouse cracked and welded

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luna negra

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central texas
First Name
luna
Truck Year
1979
Truck Model
Jimmy
Engine Size
350
Finally got around to doing a 350 SBC swap on my '79 K5. Front oil pump seal is also leaking on the TH 350 and found that the bell house has been previously welded. I was going to take a stab at replacing the seal and bushing while still in the truck but now am having seconds thoughts about the whole transmission. The previous owner must have been jumping the thing as both frame rails are bent at the bump stops. This makes me think this was probably the source of the bell house cracks and that something additional is probably wrong inside the tranny for the seal to leak. Thoughts on this from the experts? It previously drove and shifted well, just leaked ATF from the pump seal quite a bit. Should I weld some gussets on the frame or leave as is? Don't know if this a common weak point on these frames.

I have access to a another TH350 from a '75 K5 but have no idea what shape it is in as it's been sitting for 30 years. Also what's the easiest procedure to put it all back again without any assistance? Stab motor and tranny together, then add NP 203 or do tranny/transfer, then add motor? Thanks to all.
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Rusty Nail

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Uhhh...wow man, that's a great post! Thanks for coming in. Good to know ya, have a seat..

"expert"

We were hopin you were it, dang.

Always waitin on new guys huh?
If it was me and I questioned the transmission I am quick to throw them away.
That ain't no joke -ask anybody. Life passes too fast and ain't nobody got time for that!

xc_hide_links_from_guests_guests_error_hide_media

I think our friend Sweet Brown will agree.
All that time and money you are spending on that old, busted one could. have. been. looking for a better one - that's what I thought about that but wthout any assistance..ow! You can manage the transfer on your own but it may prove to be challenging it will require lots of attention.
Since you are alone it seems to me that motor/trans~  preassembled is a WAY BETTER play. Always thought that saved asloads of time even with hands around.

Great post ! They got action, pictures, carnage, and we're all pullin for ya. That's gotta help!
Be safe!
 

luna negra

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Joined
Jul 3, 2019
Posts
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Location
central texas
First Name
luna
Truck Year
1979
Truck Model
Jimmy
Engine Size
350
Was actually pretty easy to pull out together solo w/ a cheap HF scissor jack and moto lift.
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Let them down slowly, then jacked up the front end to pull out.
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Now do it all again with this donor and hope nothing is wrong. I'm gonna have to split them since the original NP203 has the 2wd conversion.
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Still wondering about the bent areas in the frame. Is this something I should address by trying to straighten or adding some gussets or just leave alone? I don't know if this will be an issue down the road or not. I certainly won't be jumping it & hitting the bump stops, but it will see quite a bit of off-road. Eventual plan is a 3" suspension lift, new shocks, and some 35"s. Anybody has any insight on the frame issues, I'd love to hear them. Thanks!
 

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