My tranny did something weird... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

xtreme80 · 03-25-2007, 01:00 AM

He didn't come home tonight

Haha anyways, now that I got my childish joke aside, my transmission shifted funny today...

For starters, 1980 C10 with a GM crate 350, TH350 tranny that was just rebuilt about 1000 miles ago.

For the first time since the break in of my new motor, I had the throttle pegged today. Shift from first to second was fine, but right before it went into 3rd at about 70mph, the engine felt as if it was hesitating. It did it 3 times, then shifted. Keep in mind my foot was still in the throttle hard.

I had two thoughts on this. My first thought was that maybe the vac hose that runs from the tranny to the carb is on the wrong port. Which port should this be hooked up to? Manifold or "timed"?

My second thought was that the fuel bowls were drying up, and it's just coincidence that it got starved right before it shifted. I didn't try it again as I didn't want to run the risk of tearing anything up if it was a potential problem.

Anyone else have any thoughts?

Srubydo1986 · 03-25-2007, 01:23 AM

I have the same stuff newish 350 and rebuilt th350, For the vaccum hose i have it hooked up directly to the manifold. (the port behind the carb)

As for shifting check the fluid just for ****s and giggles it doesnt hurt to look.

xtreme80 · 03-25-2007, 01:36 AM

Ok thanks. Manifold is what the transmission shop told me to hook it to. That's also not that I have it at. they told me to Tee into the brake booster line since I'm using that port behind the carb for my AC stuff.

I'll cehck the fluid level tomorrow. Thanks for the info.

Ivan D. · 03-25-2007, 01:52 AM

Ports at the base of the carb are generally manifold vacuum ports.

grinch4om · 03-25-2007, 08:16 AM

below throttle plates, manifold vacuum above, ported also try it again and lift slightly, does it shift? manually shift it at a lower rpm and see. you may have to adjust the detent cable and or the govenor

03-25-2007, 01:00 AM	#1
xtreme80 Wishin' I had more money! Join Date: Feb 2007 Location: Eugene, OR Posts: 1,242	My tranny did something weird... He didn't come home tonight Haha anyways, now that I got my childish joke aside, my transmission shifted funny today... For starters, 1980 C10 with a GM crate 350, TH350 tranny that was just rebuilt about 1000 miles ago. For the first time since the break in of my new motor, I had the throttle pegged today. Shift from first to second was fine, but right before it went into 3rd at about 70mph, the engine felt as if it was hesitating. It did it 3 times, then shifted. Keep in mind my foot was still in the throttle hard. I had two thoughts on this. My first thought was that maybe the vac hose that runs from the tranny to the carb is on the wrong port. Which port should this be hooked up to? Manifold or "timed"? My second thought was that the fuel bowls were drying up, and it's just coincidence that it got starved right before it shifted. I didn't try it again as I didn't want to run the risk of tearing anything up if it was a potential problem. Anyone else have any thoughts?

03-25-2007, 01:23 AM	#2
Srubydo1986 The Crazy Machanic Join Date: Jan 2007 Location: Nokesville Va Posts: 1,437	Re: My tranny did something weird... I have the same stuff newish 350 and rebuilt th350, For the vaccum hose i have it hooked up directly to the manifold. (the port behind the carb) As for shifting check the fluid just for ***s and giggles it doesnt hurt to look. __________________ 1986 Sliverado longbed 400 small block mean as hell, 700r4 trans (5 speed coming one day) * 1970 chevelle 2dr sedan Latest update June 24 2007. 1957 4 door stationwagon - pink all original needing a good restore (body great, floors bad) newest additions 1965 shortbed fleet great granddads. Been told im nuts to bring it back from the dead (still going to happen) plans-all stock with a turbo 292 inline 3 speed column shift. and thats it big block 427 and 5 speed trans and ford 9 inch theyhave no home yet thinking what to put them in and a 79 c60 trash truck um no idea i have one Last edited by Srubydo1986; 03-25-2007 at 01:25 AM.*

03-25-2007, 01:36 AM	#3
xtreme80 Wishin' I had more money! Join Date: Feb 2007 Location: Eugene, OR Posts: 1,242	Re: My tranny did something weird... Ok thanks. Manifold is what the transmission shop told me to hook it to. That's also not that I have it at. they told me to Tee into the brake booster line since I'm using that port behind the carb for my AC stuff. I'll cehck the fluid level tomorrow. Thanks for the info.

03-25-2007, 01:52 AM	#4
Ivan D. glamoros piece o' lowlife Join Date: Mar 2007 Location: Redford, MI Posts: 1,164	Re: My tranny did something weird... Ports at the base of the carb are generally manifold vacuum ports. __________________ The more I drink, the more I drink, the more I drink... diesel, reg cab, long bed, 4 across the rear, single stack, wooden stakes, and lotsa lights - the Hay Express

03-25-2007, 08:16 AM	#5
grinch4om dang its hot Join Date: Nov 2006 Location: frankfort kentucky Posts: 1,349	Re: My tranny did something weird... below throttle plates, manifold vacuum above, ported also try it again and lift slightly, does it shift? manually shift it at a lower rpm and see. you may have to adjust the detent cable and or the govenor



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