th350 problems

dre0227 · 08-12-2008, 08:09 PM

Got a th350 in my bro's 70 nova. The tranny worked great when we had the sbc in it. about a week ago we pulled that motor and put in a 454. We put a 2800 boss hog stall in the tranny.(tranny had shift kit in it already) Also hooked up a b&m rachet shifter with it. Now here comes the problem. The tranny works great when you shift through all the gears manually using the rachet shifter and hammering on it. when you just drive it normal it shifts great into all the gears. once it is in 3rd gear and your going down the road it seems like it almost goes in to nuetral. but than if you shift it into nuertal than back into drive 3rd gear works fine for a few miles than does it again. We pulled the stall and put the stock convertor back in it same problem. anybody have this problem before. Any ideas how to fix it. Tranny fluid is new and full. not over full either. thanks

Deeze49686 · 08-12-2008, 08:13 PM

when it gets hot, put it in reverse really quick,does it go in good, or does it slide? sounds like you glazed or burnt direct clutches when you dropped a BB in ft of it.

dre0227 · 08-12-2008, 10:44 PM

Did that. goes in the same if it was cold. Its just weird how you can slam through all the gears right into third and stay on the throttle and it doesnt act up at all.

camaro1 · 08-12-2008, 11:08 PM

when you are at wot you have no vacuum at the modulator so your line pressure is higher

if it is slipping when you are just cruising i would say you need a rebuild

just make sure your linkage is set up correctly,,, i have seen so many people try to set there shifter using park position to set the cable, WRONG

have the cable removed from the trans, always place the trans in 1st(low) gear, then place the shifter in 1st(low) gear,, then adjust the cable length to slide the cable into the trans linkage

Deeze49686 · 08-13-2008, 12:22 AM

in the 350, you have 2 different oil paths for the direct clutch. one in reverse
and one in 3rd gear, thats why they have that damn lipseal flipped upside down in the drum. if you dont have any slippage in R when hot, it means you have a pressure loss in 3rd gear. and the fact that when you tromp it down, it holds means that its more than likely in the drum (lipseals) or the sealing rings on the pump. either way its destined for a rebuild.

08-12-2008, 08:09 PM	#1
dre0227 Have you seen my kitty?? Age: 23 Join Date: May 2007 Posts: 934 Location: MN User is: OffLine	th350 problems Got a th350 in my bro's 70 nova. The tranny worked great when we had the sbc in it. about a week ago we pulled that motor and put in a 454. We put a 2800 boss hog stall in the tranny.(tranny had shift kit in it already) Also hooked up a b&m rachet shifter with it. Now here comes the problem. The tranny works great when you shift through all the gears manually using the rachet shifter and hammering on it. when you just drive it normal it shifts great into all the gears. once it is in 3rd gear and your going down the road it seems like it almost goes in to nuetral. but than if you shift it into nuertal than back into drive 3rd gear works fine for a few miles than does it again. We pulled the stall and put the stock convertor back in it same problem. anybody have this problem before. Any ideas how to fix it. Tranny fluid is new and full. not over full either. thanks
	[Reply w/Quote]

08-12-2008, 08:13 PM	#2
Deeze49686 I'm slap happy, bitches! Age: 35 Join Date: Dec 2007 Posts: 1,905 Location: User is: OffLine	Re: th350 problems when it gets hot, put it in reverse really quick,does it go in good, or does it slide? sounds like you glazed or burnt direct clutches when you dropped a BB in ft of it.
	[Reply w/Quote]

08-12-2008, 10:44 PM	#3
dre0227 Have you seen my kitty?? Age: 23 Join Date: May 2007 Posts: 934 Location: MN User is: OffLine	Re: th350 problems Did that. goes in the same if it was cold. Its just weird how you can slam through all the gears right into third and stay on the throttle and it doesnt act up at all.
	[Reply w/Quote]

08-12-2008, 11:08 PM	#4
camaro1 Registered User Age: 35 Join Date: Feb 2006 Posts: 300 Location: User is: OffLine	Re: th350 problems when you are at wot you have no vacuum at the modulator so your line pressure is higher if it is slipping when you are just cruising i would say you need a rebuild just make sure your linkage is set up correctly,,, i have seen so many people try to set there shifter using park position to set the cable, WRONG have the cable removed from the trans, always place the trans in 1st(low) gear, then place the shifter in 1st(low) gear,, then adjust the cable length to slide the cable into the trans linkage
	[Reply w/Quote]

08-13-2008, 12:22 AM	#5
Deeze49686 I'm slap happy, bitches! Age: 35 Join Date: Dec 2007 Posts: 1,905 Location: User is: OffLine	Re: th350 problems in the 350, you have 2 different oil paths for the direct clutch. one in reverse and one in 3rd gear, thats why they have that damn lipseal flipped upside down in the drum. if you dont have any slippage in R when hot, it means you have a pressure loss in 3rd gear. and the fact that when you tromp it down, it holds means that its more than likely in the drum (lipseals) or the sealing rings on the pump. either way its destined for a rebuild.
	[Reply w/Quote]


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