3t40 shift problem

[TurboGTU]

OK, for those who don't know me...I have turbocharged a beretta gtu...OK this ain't no regular swap. Cam, ported heads,...more boost...ok nuff said...Now my problem.. The car has been sitting for a year. Now that I got the car running...the trans seems to got into nutral when shifting gears. IE....from 1st to 2nd and from 2nd to 3rd when I WOT. Also when it down shifts from a WOT at speed....it also seems to do the same. It goes into a nutral. It sometimes does it in normal operation. The old man said it might be the TV cable that needs adjutment. But I don't know...I think it might be sticking valves.
Also can it be a oil presure issue? The oil in the trans is Amco Dex. Mer 4. Im gana run trans cleaner and flush the system and install the regular stuff or type F oil. Yea some people recomend type F cuz it has a higher heat range.
Tell me what you trans experts think.

[phantom505]

If you've beat the transmission up in the past my money would be on the clutch packs and bands. I am running into a similar problem now, but not to extreme you are speaking of.

[TurboGTU]

I don't think it could be the bands or clutches. The trans is a...well was a freshly rebuild gmgoodwrench trans. It shifted firmly to the day I decited to modify a new motor. I trans braked it to 1600 and it wants to take off....the brakes can't hold it...LOL...so I know it ain't the clutches.

[PaPaPooh]

don't use type F

do the service put dex merc 3 or 4 if you like don't over fill it

does it shift fine when it warms up?

if you need the fluid specs for the service let me know and i can look is the book

good luck

[4spdz34]

type f is fine and so is overfilling as long as u don't go too far a quart over is fine

[phantom505]

If you figure it out let me know. I'm trying to anticipate the problems we see with the 4T4X's trannies.

[TurboGTU]

Ok. Yesterday I used the car all day long on a trip to the lake. I would say about 100 miles or so. OK so Im on the on rap and its doing that 1st and nutral shit again so I said....f***it...I'll manualy shift this thing...OK as I was going to-- it shifted...SO I just went ahead and droped it into 2nd gear...bam....the engine bounces on redline (6560 rmp).. WHAT THE HELL!...So I slow down around 20 and shit to 1st...and WOT it ...right around 5K I shifted to 2nd and it didn't go in...WTF..
It feels like there's no 2nd gear. SO when I shift to D it shift into third right away. What gives?

I was watching the rpms as I was in D and punched it again to downshift...well it redlines like crazy and then goes back into 3rd...I originaly thougth that it went into 2nd...but I guess its becaust the Torque converted unlocked when I WOT it.
Has anyone had this problem?


OH one thing I forgot to mention....I am using a memcal from a 93 Grand Prix SE...could the limp mode section of the memcal cause this?

[phantom505]

It still sounds like a 2nd clutch pack problem to me. But you insist it's not. The only other thing I could think of is you have a problem with the shift solenoid, which could be caused by a computer problem.

[Cliff8928]

no shift solenoids on the 3T40.

I'd go examine the condition of the trans fluid.. I'd imagine it may be burnt/brown/murky

Cliff Scott
89 BerettaGT
89 Volvo740

[TurboGTU]

It had new trans fluid in it when I parked it last september and it has new trans fluid now....its the same thing. The day I parked it 2nd was strong as hell like the rest of the gears.. The trans was a recently rebuilt gmgoodwrench trans. I have no warrenty so im scrued there. When I shift to 2nd from a stop and excellerate...it stays in 1st....all the way to redline. if I shift to D it goes into 3rd right away. I'm thinking its a stuck valve or foward piston....if this trans has one. Does it?...

I would have known if it was slipping if there was clutch deposits in the oil or if it took off like a snail.
Thanks so far for the help. ANYTHING is apreciated. Still need more though..

[TurboGTU]

Well Im dropping the trans and installing anotherone today. Im going to dissasimble the trans to see what the heck happend. If everything looks good and is rebuildible..im going to turn it into a race tranny. Wish me luck...LOL