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TH-350 auto tranny wont go in reverse

2K views 14 replies 4 participants last post by  scottieduckfan 
#1 ·
okay so it happened like this.....i had a rebuilt tranny in my 71 buick skylark. it got low on tranny oil and was driven around and eventually started slipping and was parked. I have regained interest in getting to go so i got a tranny from a diff. car to replace mine. It would no go into reverse, but 2 and 3rd worked great (not sure about 1st). so i took out the brains of the two and put together one good one (even though some of the reverse clutches looked a little burnt). No reverse again. so i bought a Red Alto clutch pack to fix the problem. put them in along with a th350 hp shift kit. it was totally cleaned, new fluid added....the whole shebang......NO REVERSE!!! Does anyone have any idea what could be causing this? I felt it **** 3 times so 1st is working, but it seemed kinda difficult to notice it. PLEASE HELP!!!! also off subject....i have been hearing that people use ATF fluid. does it help or hurt? anyone know?
 
#2 ·
scottieduckfan said:
okay so it happened like this.....i had a rebuilt tranny in my 71 buick skylark. it got low on tranny oil and was driven around and eventually started slipping and was parked. I have regained interest in getting to go so i got a tranny from a diff. car to replace mine. It would no go into reverse, but 2 and 3rd worked great (not sure about 1st). so i took out the brains of the two and put together one good one (even though some of the reverse clutches looked a little burnt). No reverse again. so i bought a Red Alto clutch pack to fix the problem. put them in along with a th350 hp shift kit. it was totally cleaned, new fluid added....the whole shebang......NO REVERSE!!! Does anyone have any idea what could be causing this? I felt it **** 3 times so 1st is working, but it seemed kinda difficult to notice it. PLEASE HELP!!!! also off subject....i have been hearing that people use ATF fluid. does it help or hurt? anyone know?
Did you remove the rear piston from the case?

What was the clearance of the clutch pack?


Did you air check this clutch pack in the back of the case after the center support was installed?


:cool:
 
#3 ·
ya absolutely everything was taken out and torn apart. everything was cleaned very nicely. i dont know the clearance of the clutch pack, we didnt check we just put everything back together and we made sure everything was in the right way, all the clips and retainers put back. We didnt air check the clutch pack after everything was put back together. is there anything i could try with the tranny still installed. I have took that in and out at least 6 times now trying diff. things. I am going to check the piston that is supposed to push against the band when reverse is ingaged. we took it out, but the ring around it wasnt as tight as a diff. one i have. maybe not enough pressure??
 
#5 ·
if you are refering to the piston that is in the brain above the tranny pan then thats the one i am talking about. it came out pretty ez without any special tools or anything. I am going to take it out tomorrow. We didnt replace the seals, we used an old one that locked, and im thinking that maybe its not sealing right. the other one that i have which im going to put in tomorrow doesnt lock and would have much more tension to hold it in place. Are there anything besides the metal ring that is there that i am maybe missing?
 
#6 ·
scottieduckfan said:
if you are refering to the piston that is in the brain above the tranny pan then thats the one i am talking about. it came out pretty ez without any special tools or anything. I am going to take it out tomorrow. We didnt replace the seals, we used an old one that locked, and im thinking that maybe its not sealing right. the other one that i have which im going to put in tomorrow doesnt lock and would have much more tension to hold it in place. Are there anything besides the metal ring that is there that i am maybe missing?

I see some confusion here;

there is NO band for reverse in a t-350 trans. There is a piston in the rear of a t-350 case that has 3 square cut O-rings on it. This piston has a retainer with springs under it that must be removed to get the piston out. Was that removed and the O-rings replaced?

I am not sure what piston above the pan you are talking about. There is a servo for the coasting band that is covered up by the valve body.
 
#7 ·
is the thing you are talking about on the passanger side near the rear? We did take it out because when we bolted it up this last time it was leaking. There was only one rubber o-ring that we replaced, there was a spring, and a circle clip that holds it. it doesnt leak anymore. is there supposed to be more o-rings?
 
#9 ·
scottieduckfan said:
is the thing you are talking about on the passanger side near the rear? We did take it out because when we bolted it up this last time it was leaking. There was only one rubber o-ring that we replaced, there was a spring, and a circle clip that holds it. it doesnt leak anymore. is there supposed to be more o-rings?

no.....

inside the case of a t-350 at the rear is a piston with a retainer and springs.

It sounds like you do not have a t-350.

I suggest finding a trans professional to help you.
 
#10 ·
scottieduckfan said:
.i have been hearing that people use ATF fluid. does it help or hurt? anyone know?
ummmm........ :confused:

ATF = Automatic Transmission Fluid

what did you fill your trans with?

scottieduckfan said:
I felt it **** 3 times so 1st is working, but it seemed kinda difficult to notice it.
If you felt it shift 3 times, you felt

1-2 shift
2-3 shift
3-4 shift

The TH350 is not a 4 speed trans
 
#11 ·
i meant atf type F, the stuff they use in fords. when i said it felt like it shifted 3 times i meant into 1st, into 2nd, and into 3rd....Crosley, as for the piston you are talking about im having a hard time picturing where it would be at. Is there a bolt right next to it.....that i think is supposed to relieve pressure????
 
#12 ·
scottieduckfan said:
i meant atf type F, the stuff they use in fords. when i said it felt like it shifted 3 times i meant into 1st, into 2nd, and into 3rd....Crosley, as for the piston you are talking about im having a hard time picturing where it would be at. Is there a bolt right next to it.....that i think is supposed to relieve pressure????
So, you felt it shift 2 times, not 3, correct?
 
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