My turbo 400 just STOPPED going? Help, ANY ideas???

I will TOMMORROW!!! I live in SPOKAN-DIEGO!!! It is 23 degrees out side and the car is out in the street, PLUS it is dark, sorry,.... I can stand 150 degree's outside BUT I am the BIGGEST ***** there is when it comes to COLD!!!!!!... I wil post my findings tomorrow night, just hold your breath for me please....Ken

 

I had rebuilt a guy's TH400 (in a 4x4 chevy snowplow truck) that had a broken output shaft. I don't think that's what is wrong with your trans. I suggest:

1.) Oil pressure check in Drive and Reverse

The oil pressure test port is on the driver's side of the case, between the shift lever and the electrical connector, and a couple inches above the oil pan rail. The plug should be 7/16" hex and has 1/8"NPT threads. Use a 300psi gauge and appropriate hose.

2.) Drop the oil pan and look for any metallic debris.

3.) Report your findings on #1 and #2 above

 

I will drop the pan tomorrow, but I (like everyone has suggested) have no way of doing a pressure test, ALTHOUGH, like I have said, how would my ****** WORK one day, and then the NEXT day it won't????? This just doesn't seem right!!!! There was NO problems up to the day of driving it last, plus all last summer I put HUNDREDS of miles on it with NO problems!!!!!! Just one day it works, one day it doesn't??????????????????

 

I would like to know what happens too.

 

I rebuilt transmissions from 82 to 06 for a living, cut my teeth on 400`s , more than likely the filter is clogged, they are notorious for this problem. However, that only means that there is an internal problem that is creating the debris that clogs the filter. Changing the filter SHOULD buy you some time before it happens again.
Get over it working great and then not....you`ve seen it with a light bulb, right ??

 

Ummm, not sure what you mean???? A light bulb????

 

I do GM trans work for a livin also. Get the pan off and report back. I have changed output shaft to this has nothing to do with it. Vac and modulator has nothing to do with it. I bet on plugged filter and now colder fluid can't get through. Also a plugged filter doesn't for sure mean a junk trans, maybe the guy who fixed it last time left a ton of rag lint behind and now it lives in your filter!

 

Update again...
I froze my *** of taking off that pan!!! FOR nothing!
After pulling the pan, AND filter, the fluid stunk like ***!!! IT IS BURNT! But since I bought a new filter I took a chance and cleaned as much of everything that I could, replaced the old filter with the new, new gasket, put it all back together, and then added the new fluid to top it all of, and then I let the motor run for about 20 minutes, just to make sure everything was up to operating temp. I put the selector in ALL the gears for a few moments to make sure the fluid is everywhere, and then I put it in reverse, and it moves... 5 friggen feet, and STOPS!!!!! I put it in drive and NOTHING, 1st, 2nd, drive again NOTHING!!!!!Reverse again and now it WON'T move!!!!! I double check the level and it is right on! So I guess my ****** is GONE!!!! I just don't understand driving the damn thing for a long time and then the next time it is put in gear it is TOAST!!!!! Pissed, stumped, and Mad....Ken

Thanks for all the advice and help though guys, I appreciate it

 

No chance the spider gears are broken in rearend.Ck to see if driveshaft is turning. I broke alot of the in my 1959 chevy and it would do like you are saying.

 

Sorry to hear it wasn't the simple fix, I once drove my car to my friends, it drove fine over there but wouldn't start 15 minutes later. Two hours of checking every wire with an ohm meter and trailering back home,it was the 5 dollar part, I was pissed too.

 

you dont have any teen age boys who could of snuck the car out when you wern't looking?

 

NOPE!!! NOTHING turning! I had the wife in the car puting the column shifter in all the gears while I watched to make sure the gear selector was moving (it was) and to make sure the driveshaft wasn't turning also(it wasn't) !!! By the way, there is NOW a faint "whine" sound when it is in reverse, NO sound in any af the forward gears, and an even FAINTER whine sound when it is in park??????

 

No, But I wish, at least that way I would have known what happened!!!

 

jack up the backend and see if it'll run through the gears, listen to the noises.

 

Wierd. I have a busted TH400 but it still works great in low, no reverse (will back up on level pavement if you just put it in gear and let it go on the idle, give it gas and it slips like mad) and supposedly no high - don't have plates on it so I don't take it out on the road to see for myself. I would think that something's causing it to have no pressure if it won't go at all.

If that's a converted 4wd trans, a short tail should go in there, if you get another one, get the yoke with it just in case they're different splines. Pain in the *** to change it out, but at least you didn't bust some one-off part a guy's going to have to make up from scratch.

Also, someone asked. Wagoneers had a TH400 until '72. Through '70 they use a universal pattern case that's the same pattern as 58-66 Buick Nailhead (although you need a 64-66 crank to put one on the 58-63 motors). Kaiser-Jeep also bought 350 V8 motors from Buick through '70 or '72. We had one a while back with the Buick 350, an adapter going from BOP pattern to the old pattern, and the TH400 trans.