OEF14vette

Okay so a the title says i recently started having an issue with the trans in my Ls swapped 74 corvette. It is a TH400 10" Nitrous converter 34 Element sprag with an overhaul kit from jakes In texas. The car just started having the issue after the last fluid and filter change that when i launch the car or go WOT in 1st then bang 2nd it almost is like it hits neautral reving way up but as soon as you pedal it/lift and nail it again it is fine. The fluid level is perfect and i adjusted the shift cable to TCI spec 3 times now and still the same thing. It is fine if i only take it up to 4500-5500 rpm and shift it but anything higher then that it slips or "hits neutral" Mind you the trans was built in september and has 15 1/8 mile nitrous passes, 500-600 street miles and 2 days on a dyno where it was pounded pretty hard on motor and nitrous. I am open to anh and all suggestions. We are supposed to be racing the 7th so time is evading me fast. Thanks fellow LS1techers

OEF14vette

Also it has a transgo kit in the valve body, the one that allows you to run in 3rd and it will shift auto off the governor or manual if pulled back to 1st and will hold each gear until you shift it. Forward pattern nothing exotic. Thank Gents.

Byrdman11

iTrader: (2)

Sound like sprag is going out. I would put it and put it down and start checking clutches for second and sprag.

Nostang

iTrader: (4)

Before pulling the trans check the shifter cable. My car did this last season and come to find out the shifter cable stretched. A new shifter cable fixed the problem.

OEF14vette

Okay, I have a spare sprag if it comes down to that. I've adjusted the cable per the TCI instructions and it still did it. I loosened everything up last night and re adjusted for peace of mind and if the rain holds out take the car for a rip after work tonight. Also this may sound dumb but are their any real do's or don'ts with his set up? As far as burnouts at the track or street driving it and manually shifting it? I know fir reverse pattern their are but all I have is the trans go 1&2 kit and 4L80E intermediate pack with 4 frictions and steels and the 34elemnt sprag along with other mods Jakes Performance advised me to do. Thanks for the replies.

clinebarger

I'm guessing that you have a 4L80E Direct Drum? How did you fit 4 frictions & steels in a TH400? Not running a Wave Plate in the Intermediate Clutch is HARD on the Sprag when running a Iron Drum.

OEF14vette

IIRC It is a 4 clutch stack with the 4L80E .062" frictions and .065" steels without a wavy... It is an early TH400 with the smooth drum like the 4L80E so i was able to use a 34 element sprag in it and the TH400 pressure plate. I was ecstatic when i put it together fired the car for the first time took it to the dyno tuned the car with zero trans hiccups and raced a season on the ice and street driving this spring/early summer with it. was really hoping i did this right and took advice from the right people... If it help so you know what it is its the stage 2 TH400 kit from jake shoe which i in no way am implying it is his fault or his company's fault i am having an issue just making everyone aware of what i put in my transmission so we can solve the mystery. Thanks again for everything

wht/73

Have you reached out to Jake for advice?
That would have been my 1st call.
I'm sure being a customer of his, he would be more than helpful offering troubleshooting advice.

OEF14vette

I have not contacted Jake yet, I plan to do so today I know he is busy and like to deplete my own resources first before calling with every problem. I know we have a plethora of knowledge on here and use this as one of my first resources when issues arise. I will report back after talking with Jake and getting his advice. Side note WHT/73 how do you like the 4L80E for at the track? I been debating making the leap but been unsure I know the street ability will be incredible compared to the 3 speed

wht/73

Haven't gone yet. Been to busy and had a restall done.
But I'll report back.
Love having 4th and lock up!

OEF14vette

Well I loosened everything again and started fresh with a cable adjustment it must have been just so that one turn was too much and one in was not enough so I fiddled with it and have it so it bangs second gear every time at 7 grand throwing the car sideways ... I appreciate all the responses and knowledge of the folks that put their 2 cents in. Now off to the track to see what it does in the 1/4 on the 7th at the Real Street drags I think we will put the 300 pills in and let er eat.

Nostang

iTrader: (4)

Glad it was the easy fix!

OEF14vette

That makes 2 of us i really didn't feel like pulling the trans and going through it over this weekend. On the topic of transmission failures and what not anyone out there with a TH400 how do you do your burnout at the track? In the past with Manual valve bodies we did high gear burnout staged and went this car has a forward pattern valve body with the trans go 1&2 kit so if i put it in 3rd/hi it will auto shift at say 4500rpm because of the governor but i can start in 1st bump 2nd and roll out or go all the way to 3rd for wheel speed and keep the rpms lower? Just looking for the most effective and least parts stressing way to get the tires hot. 275/50R15 drag radial 3:55 rear gear stock th400 planetaries. Thanks and happy 4th of july weekend.

Nostang

iTrader: (4)

I have read and was always told to start in second shift into third and then roll out of the burnout. Here is a good thread on automatics and burnouts.

http://www.yellowbullet.com/forum/sh...=120213&page=3