RATBOX

iTrader: (26)

I was talking with another member about it in a different thread so I'm just going to copy and paste my other post of the problem's description. Just wondering if any of you have seen these types of symptoms from an auto trans.

It's really the oddest I've ever seen an auto tranny act and I don't know that explaining it here would make much sense. Keep in mind, the TH400 trans is completely fresh, race prepped with a rmvb and the stall is from a verrrry reputable builder and is brand new.
But near as I can tell, it feels like there is a "bind" in the transmission. The car's a dog if you go beyond 1/4 throttle and the front pump is screaming in 1st gear at all times while in gear, then you can't really hear it when you shift it to second. Car shifts and drives fine just cruising around, but if you give it 1/2 or more throttle the car acts like it doesn't want to move and if you stay in the throttle in first and shift to second, it accelerates better after you shift to second. But still not as it should. Again it's like something is bound up inside the TH400 and it frees up slightly when shifted to 2nd. This is probably a shitty description, but it's the best way I can think to explain it.
Now, see it doesn't slip unless you reeeeally hammer the throttle. It literally seems like something is holding the car back. Also, it's nothing with the motor I'm more than certain, it wouldn't act this way anyway even if it did have a problem. Something is definitely sketchy with the th400. But what's odd is that it shifts ok. I dropped the pan, it had some clutch material in it. More than I'd expect to see with 15 miles on it, but far from enough to raise concern. No metal and the pickup tube looked to be in correctly and sealing as it should.

Oh, and I checked the converter spacing tonight while I was at the shop. With my shims in place I used, the gap is exactly an 1/8th of an inch worth of spacer with the converter bolted down to the flywheel. Converter had clicked 3x going on, spun freely and everything seemed as it should. I've had several race purposed auto's over the years and have either had them work right, or not all. So, I'm at a loss on this one. I'm no guru by any stretch of the imagination and will always be learning, but these symptoms don't even make sense to any of the "more trans educated than me" people I've talked to in the last few days.

What are some of your ideas, internal leak, valve sticking, or is this another one of those issues no ones ever seen?

RATBOX

iTrader: (26)

No one?

PBA

How is reverse? Any drag? Once you are in 3rd gear gear (high), and you give it 1/2 throttle or more without it downshifting, is the problem still there?

Jake's Performance

iTrader: (2)

Sounds like an issue with the rear band being too tight or a roller clutch problem.
The pump noise, does it only do it when moving? Or when sitting still?

Vince B

iTrader: (1)

Being that you found clutch material in the pan after the little big of miles you have put on this thing, I would get it back to the builder to look at. A cross leak is a possibility and would make sense here. HTH Vince

chris718

Is the car harder than normal to roll in neutral with the engine off?Is it hard to roll in neutral with the engine running?

Mattsv8

iTrader: (7)

i was thinking band tight for some reason. or cross leak

RATBOX

iTrader: (26)

Car rolls fine in neutral, pump only makes noise in first gear.
Reverse is fine, but I never give it anymore than part throttle. Which it's had no issues with, it's when you get more into the throttle that it starts acting stupid. The problem is in every forward gear, it's seems to "free up" as you shift to each gear. To explain clearly, it's really sluggish in 1st then you shift to second and something seems to free up, shift to 3rd and slightly better but something is still not right. In any gear if you try to go WOT it slips. At this point I'm thinking it's a build issue with the TH400. The trans went back to the builder on Thursday, hoping to have some answers Monday. Just hoping my custom converter didn't end up with trash in it somehow.

Jake's Performance

iTrader: (2)

What brand valve body does it have?

A cracked servo piston could cause issues too.
The pump noise in first is odd, possibly a massive leak internally, loose servo cover..

RATBOX

iTrader: (26)

It's a hughes I believe, rmvb. Whatever the issue is, it was there from the get go.

RATBOX

iTrader: (26)

*update*

I hate when people start threads like this and never post up what the problem was/is when they figure it out.

SO, figured out what the issue was. The converter was over-engaging the pump. Looks as though there was a miscommunication with the converter builder. The converter is built with a longer pilot than your typical TH400 converter. NOW, the issue is that when I used the TCI kit the provided spacer combined with the longer pilot pushed the converter in to far towards the trans. I had questioned this when I was putting it together and I called the converter builder back and I don't think he understood what I was explaining and I ended up assembling it thinking it would be ok, which is what I'd gathered from the converter builder. No biggy, somehow the converter and the pump appear to be fine. Lucky.

What's a person supposed to use? I need something that'll allow the converter to move closer to the crank and center & support the converter in the end of the crank like it's supposed to be. Because as it is now, if I leave the spacer out the converter has no way to stay centered.

Thanks for everyone's input!

RATBOX

iTrader: (26)

Was a simple solution, just had the misbuilt pilot cut down on a lathe and we got the correct spacing. Works like a champ and mutilates drag radials through 3rd!

Jimbo519

I think I'm having the same problem. In 1st gear the Rpms won't rev past 5000rpm but it doesn't do it all the time. 2nd and 3rd no problem hitting rev limit at 7000rpm.