DESPERATE: I need a transmission EXPERT

Well I guess I'm not sure what you mean by the inner and outer weights. I thought there was only one set? Here is a pic of one, I put the vacuum line pieces behind point B . The trans has a stock pan. I will also try and use one of the other kickdown soleniods and I'm also going to get a new modulator valve. Snowed last night have to wait for the roads to clear before I can test drive it again

 

Behind point B will push both weights out.

The Th400 came with a deep 3" or a shallow pan 2".
If you have a deep pan and the filter and intake pipe are for a shallow pan it could be starving for oil? Maybe that's why you loose third gear and it won't downshift to second.
Also, did you tighten the filter with washers or did you leave it floppy?

 

I left the filter floppy. Do you know how long the intake pipe is for any given pan depth?

 

Floppy is good.

Short intake pipe is 4.845" and the long intake pipe is 5.845".
Also make sure the pipe is installed as it should?

 

Thanks MR4Speed . I hope to check this info out tomorrow night. I hope the roads will be clear enough from the snow for another test drive on Friday. I should be able to give another informative update by then.

 

If it's still looses third gear at the next test drive check the oil on the dipstick if it's air rated. If it is the pump is sucking air in!
Did you take the vacuum line pieces out of the governer, if you leave them you will not know when everything is working as it should.
Good luck...

 

Gee, this is a basic item and I am sure you already have checked - but - is it possible the tranny does not have enough fluid? Wrong dipstick or something? I realize that it is probably not this, but this is something you can check while you wait for the weather to clear.

 

I've been checking the fluid and haven't seen any sign of airation. Haha, ya I took the vacuum liine pieces out after I tried then.

 

Well I have 3 dipsticks and tubes and they all seem to be the same length. But I didn't know there was 2 different depth pans as MR4Speed pointed out. So if I have a shallow filter/tube set then maybe I could be low on fluid (at the filter)....????

 

A couple more thoughts: There are 2 types of kickdown solenoids, early with aluminum body, and late with stamped steel body. The early style used a aluminum gasket, and the late style had a molded in rubber gasket. I have heard of problems caused by using the aluminum gasket with the late style solenoid. Also, If the trans was low on fluid, the most likely symptom would be a delayed engagement when shifting the trans into gear.

 

Well on my way to the garage to finish working on the trans. Last night I took down the pan and the valve body. Pulled the modulator and the governor. I double double checked the modulator and the governor. I blew out the passages in the case where the governor tubes go in. Blew out the screen and the valve body where the tubes go in and the tubes. I checked placement and number of check balls. I checked all pistons in the valve body. They were all moving freely. I gave 1-2 shift piston an extra look. The only thing that I found was that the kickdown solenoid was loose, really loose. I tightened it and gave it 12v to see if it was working and it seened to be. I even had my nephew jump in the cab and shift it through all the detents to make sure it wasn't inbetween gears. I checked filter to bottom of the pan clearences. So with all this. The pan is on and I'm going to fill with fluid and try for another test drive........STAY TUNED!!!......I will update tonight.

 

Bingo

 

squirrel is right.
A turbo 400 WILL shift with no vacuum to the modulator valve about 4500 RPM's. I had a rubber hose collapse on mine and with enough RPM's it shifts
really hard into second but third was ok.
Sounds like a vacuum or modulator issue.

 

Well I took it for a test drive. The roads are still slick so it wasn't much of a test drive. All seems to be fine. It shifts up, it shifts down. I think my nephew is ready to roll. Going to take it for another ride tomorrow, just to double check.

BUT, boy don't I feel like a freaking DUMB A$$. All this trouble because I forgot to tighten two bolts. Well I want to thank you ALL for the replies and support.

 

Good job!

 

Thanks

 

The suspense was killing me! Way to hang in there.

 

Thank God for that!
Maybe I can get a good nights sleep now!

No, seriously, well done.

Mart.

 

Thanks for giving us the ending! I've never rebuilt a trans before and hope to soon so I've been reading all your posts.

Glad it was something simple and *free*!

 

Good to hear you found the problem.

Well done.

 

Well done. Good info for all of us.

 

so it was the kick down solenoid the whole time?

 

Ya it was. I actually am still using the same modulator and governor that was in the trans when I started. The kick down solenoid was the only thing that seemed wrong when I took it apart this last time, and now it works. What a B!T@H, huh.

 

Boy, I'm glad I NEVER made a mistake like that! . Glad you got it fixed. And now just think about how much you know about th400's than you did when you started! Plus, we got to learn with you.

 

Well I think I might try a 700R4 or a 350 turbo next.

 

Congrats

turbo 350 is real simple

700r4 is a whole other animal

 

Well the roads were bare so we took the truck for a REAL test drive. Normal driving, the trans seems to shift great. When you get right down and dirty and give it HE!! it seems to hold in gear to long and you have to let off the throttle for it to shift. I'm guessing it may be the modulator, so I'm going to put in the new one. I may have to adjust it. Is it in for sooner, or out for sooner on the adjustment screw???

 

A good working modulator has the most affect on part throtlle shifts. So if part throtlle shifts are not too late i doubt it's the modulator.

The cause might be somewhere else like maybe high line pressure or a too heavy spring at the shift valve but if you use a governer with heavier weights it will shift earlier at full throtlle.

At what rpm does it shift?

For the modulater adjustment, screw in for later/firmer and out for earlier/softer shifts.
Only adjust 1/4 turn at a time.

 

Normal driving it shifts 1st to 2nd around 2100 to 2300 rpm, 2nd to 3rd it shifts around 3000 to 3200 or 3300 rpm.

 

And how much rpm at full throtlle?