4L70E No forward or reverse gears
4L70E No forward or reverse gears I was driving down the highway in my tbss, awd, built 4l70e, in 4th gear, converter locked and temp at 138. I went to accelerate and nothing. I tried knocking it down to 3,2,1 nothing. Tried reverse and nothing. In all those gears the truck freely rolls. In park it stays locked. I didnt hear any noise to make me think that something broke. Before I pull the trans do you guys have any thoughts on what happened?
Broken input shaft or failed pump would be my guess , Where did you get it built ?
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I had a local Grand National racer build it up. It has a 300mm steel reinforced input housing and heat treated input shaft. I figured that would withstand some regular driving. How would a fail pumped cause these symtoms. i only ask becasue I don't know. Would a failing pump cause lookup issues with the converter? I had the converter stick in lockup upon startup but as soon as I realized this I disconnected the tcm and the neg bat cable and its been fine since.
A failed pump well will not pump no pump no move the other symptoms may be related
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That would suck. That pump is brand new with less than 1000k on it becasue I had a converter go and take out the pump with metal shavings. Is there any ways to check and get some ideas before we tear into it? Maybe its something electrical?
Unhook a trans line start truck if no flow then no pump
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Thanks for all the great info. Ill try that tom night. Could an electrical problem cause this. Ive heard alot of GTO guys and some other tbss guys having wierd trans problems out of the blue due to elect issues.
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Unfortunatley not a no movement situation You are looking at a pump hydraulic or mechanical failure 
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