Th350

[Randy 2811]

Just installed a 406 dart engine built by TriStar. Also put a TH350 stage two in from Performance Automatic. When I shift from park to reverse to neutral to drive, I have nothing in drive. If I shift from 1 to 2 to drive, it goes into drive, but slips bad. 1, 2 and reverse have no slippage!!!! It's not the linkage or detent. Checked both. Performance Automatic is telling me this isn't possible. Can anyone shed some light on this for me????? Thanks in advance.

[kwmech]

How much oil did you put in the trans? A complete fill is going to be at least 10 quarts or more

[Randy 2811]

Added 5 quarts. Ran thru gears topped off with 12 total quarts. Deep pan.

[So.Cal.Super]

Did you pre-fill the converter? wondering if its a pump issue and i'm guessing it's a stall? Any idea how high? I've seen then too high for drive-train combo specs.

[So.Cal.Super]

Just popped into my head, Could it be a Manuel Valve body and when you put into drive your actually trying to take off in 3rd?

[Bigdav160]

Sounds like the low roller is not any good

[Randy 2811]

Not supposed to be a manual valve body. Why when I go reverse, neutral, drive, there is nothing there? But if I go into drive from second, then it goes into gear (but slips). 2500 stall converter, and I did pre fill it before I installed.

[Randy 2811]

First, second and reverse are all there and strong.

[Ironangel]

Originally Posted by Randy 2811

First, second and reverse are all there and strong.

Manually? Does it shift up from 1st into 2nd and then 3rd from drive without manually shifting? In other words, If you have to manually shift through 1st and 2nd, then once rolling 3rd is there, Big Dave's right, low reverse roller clutch is out. What exactly does that shop do to a "stage two" 350THM?...One of the first mods I would do is replace the low roller clutch and sprag with a later model and way tougher 700r4 clutch and hardened sprag...If their stage two does that, then it may be on the shop...

[Randy 2811]

when I go into drive at a dead stop, nothing is there as if it were in neutral. If I pull it into second then back into drive, it then goes into gear, but slips bad.
This is all from a dead stop.

[Ironangel]

Originally Posted by Randy 2811

when I go into drive at a dead stop, nothing is there as if it were in neutral. If I pull it into second then back into drive, it then goes into gear, but slips bad.
This is all from a dead stop.

Low reverse roller clutch... PS. The longer you drive it like that, the more you risk damaging the case and circulating metal fragments throughout the tranny as well as the converter...Need to know in detail what the shop did to your tranny and how many miles were logged before this situation occurred? A stage 2 rebuild kit doesn't necessarily constitute a stage two Heavy Duty or Street Strip transmission...Heres a pic of a low reverse roller clutch that fragged two years after the transmission (350THM) was rebuilt using a stage-4 heavy duty rebuild with a Transgo shift kit...Unless specified, most shops dont make performance mods to the tranny's they sell...I learned this the hard way through Monster Transmission and their stage two 350 turbo tranny. Only their stage-3 got the performance goodies and you paid nearly $2K for that tranny. I have a stage-4 kitted, performance modded 350THM (hardened sprag, B&W 700r4 roller clutch, adapt-a-case case saver, http://adaptacase.com/a74761dac.html, drilled, tapped, and plugged duel feed directs, with the transgo shift kit, $800 plus shipping with a 90 day parts and my workmanship (because I build them) guarantee...I built this tranny for a 72 C-10 that tows nearly 9000lbs of trailer loaded with another 72 C-10 drag/show truck sporting a 350THM behind a 500 HP BB 408...350 turbo's will withstand 600+ HP with those mods...Easily! Because they're 15lbs lighter, have less rotating mass, and are geared lower, than the 400THM's..."just sayin"
~Ghostrider~ The cracked support Some of the debris that was laying in the pan after the low roller clutch let go...

[Randy 2811]

This transmission has zero miles logged on it. Did this as soon as I put it in. I paid $1900.00 for it with convertor. The build sheet says it has : street performance valve body, OEM servo, OEM input shaft, aluminum pan w/drain, raybestos HP clutches, HP race sprag.
It's advertised to handle 550 hp. My engine was dyno'd at 526hp.
They will warranty it, but I have to ship it clear across the country.

I just put it in and was hoping to fix it in the truck without pulling it and shipping it. My engine pulls 11lbs of vacuum at idle. They told me that might be the problem. What does the vacuum modulator have to do with it going into drive at idle????


Again THANKS for the help!!!!

[Bigdav160]

Modulator doesn't matter. It's possible that the roller clutch was installed upside down in the race. It's not easy but it can be done.

[Ironangel]

The low roller clutch is deep in the tranny, it has to come out of the vehicle and be disassembled...I paid $1800 for mine but that included a cooler, 2000 stall converter, and a case of Schaeffer's #204SAT All-Trans Supreme®...That price tag is what motivated me to learn the "dark art" of automatic transmissions. The 350THM is easy, parts are cheap, and there's a satisfaction and peace of mind when you do your own work.

[Randy 2811]

I pulled it this morning and they are going to send a freight company to pick it up. Been a heavy equipment mechanic all my life, rebuilt automatic transmissions in dozers and loaders. Never been into a TH350. Wouldn't know where to start.

Thanks for all the help from everyone!!!! I hope when they get it they will tell me the truth about what they find.

[DBK81]

I'd be interested to hear how this all turns out. Sub'd

[Randy 2811]

Me too!!! I will let you know.

[Randy 2811]

Was a lot of glitter in the oil when I drained it.

[DBK81]

Yikes that's never good.

[drewbert41]

Glad to hear they are going to make it right. Sounds like you could have easily fixed it yourself though. There are a lot of people on here who knew nothing about transmissions and bought a book and rebuilt theirs. They say it is easy but I am not sure if I am ballsy enough It is one of the most popular transmissions on the planet so that helps.