blown 346

iTrader: (25)

The truck was fine all day today, that is until i put full load on it and made a pass from 30 to 120. Got up to 120 and shifted into the last gear and I head a snap, Not loud, no grinding, or any other noise. Then the truck just revved up in every gear but park still works. Ive run the truck multiple times and it never skipped a beat until today.



I checked trans fluid and its full and clean, not burnt. No leaks. The truck has a 4L80E conversion with a converter and a full motor build.



I checked the shifter cable and it was still connected but was binding on the trans pan, so I fixed that and there is now clearance between the pan and front driveshaft. started it and put it in gear and nothing, Trans temp after the run was only 120. I have no lights.



I bought the truck 2 weeks ago from a member on the SSS site.. Has a 408 with a converter, TVS 2300 at 14 PSI, the trans is supposed to be built. The truck makes a little over 800 HP on a AWD dyno. I would assume if the T case chain snapped i would destruction all over instead of just a snap. It literally sounded like a cable that broke.



I spent alot of money on buying this and dont want to spend unnecessary money if I can figure this out.



Any help would be appreciated. Mike

FFDP

iTrader: (2)

Did you give it the beans in D4?

Just curious because you can break parts in D4.

Otherwise it does kinda sound like the input shaft snapped in two if you have no forward or reverse at all.

blown 346

iTrader: (25)

Yes I did in D4.I gave her all she had, I was in drive and the truck just shifted into 4th gear shortly after I pegged the speedo. Correct I have no 1st gear all the way up to reverse. I was reading up on the input shafts snapping, and seen a guy who makes them to support more power than Im making now on Boost only, But Will I have the same problem again when i use my Alky, I havent used that yet. The truck makes a little over 1000HP at the Flywheel on boost, On Alky It makes me nervous to even bring the thing to the track again.

I have just read that if the input or output shaft breaks you wont have park and I still do, It was said the problem could be either the Pump or converter. Someone else had the same issue as me and it turned out to be his converter that fixed the issue. Anyone else have this issue or agree on this fix?

I dont have time to rip into this and seperate everything and fix it myself due to having twins. Would you happen to have a idea of a repair cost? I have a trans guy here in town that builds race transmissions and has built them for me before. But this is alot different than a F body trans where its easy to pull and put back in. I do think it might be the input shaft since I have seen so many people breaking them.

smokeshow

iTrader: (16)

Sounds like a rolled overdrive sprag. If that's what broke it will need a full rebuild. Small part and easy to get to/fix...but if it breaks it sends shrapnel through the trans.

blown 346

iTrader: (25)

That makes sense. Ive shattered a sprag before but never lost all gearing. I did have neutral become drive, and the gearing all over the place, let the car sit and was able to drive it home like nothing ever happened. Ill have to wait and see what my trans guy says whch Im sure i wont want to hear as the trans is already built.

smokeshow

iTrader: (16)

You could try putting it in a forward gear other than drive. Pull the shifter into 3rd and see if you have torque at the wheels. If you do its definitely that sprag. Wouldn't try driving it either way.

blown 346

iTrader: (25)

It doesnt go anywhere, trans shop said I rolled the forward sprag.

madmann26

iTrader: (7)

Chubbs878

smokeshow

iTrader: (16)

Wrong sprag bro.