dath

Well I was working on my TH400 tonight trying to replace the front seal behind the torque converter before I drop my new engine in and I think I may have used the hammer and screwdriver a bit over zealously while removing the old seal. Here's a picture of what I think I did (may have already been that way :rolleyes: ) :


Question is, what do I replace here? I'm guessing that this is the pump, but I really have no clue. I'm thinking those bolts in the picture are the ones that I would take out to replace this (they are all the way around the front), but I'm not sure... Please say I don't need to have this rebuilt now. How hard is this to fix?

Thanks!
-dath

vette_net

An old man once told me if it is working Don't Fix it I have followed that rule for most of my life and it works. If I were you I would take it to a tranny shop and have them remove the old seal and see what they say. Good Luck

arrio76

You didn't do anything to create that. It you look at the pump center bushing, it is unscathed. That dent/ mark is suposed to be there.

mrvette

this is not great, BUt tap the new seal in, and you should be fine...from what I see....look close for other cracks as the casting LOOKS like further damage may have been done....hard to imagine that sort of break otherwise...but if there are no cracks....just use it....

GENE

dath

vette_net: I've heard that same advice before... Thing is, my seal was likely leaking, just look at the picture, I think you can see evidence of that... Even if it weren't, I'd think it would be prudent to replace the seal while the engine is out and before I drop in the new torque converter.

arrio76: I really don't think that the "dent" is supposed to be there. It is more of a hole than a dent and it looks like some metal fell in there. I need to look at it in better light today to see... You sure that's supposed to be like that? I wish I knew what a new piece looks like.

Gene: Was thinking about that. I was really wondering if that's not just what the last guy did and maybe my excessive hammering wasn't really the cause, but it sure seems like a pretty big coincidence that I picked that side to hammer against the seal on. So is this indeed the pump? Maybe I could just replace it anyhow? I am a bit worried that there may be other issues with the pump as the pilot on my old torque converter broke at some point. I don't know how to tell if there are issues with the pump. I cannot wiggle the outer shaft at all, but I can wiggle the inner shaft side to side a bit. I really wish I knew what I was looking at, but my book on the TH400 is in the mail still :rolleyes:

arrio76

Dath, That hole/ dent is indeed suposed to be there. It is the front seal drain back hole. The hole provides relief/drainback for the fluid that lubes the pump bushing. It exhausts to the backside of the pump and back into the pan. If it wasn't there, then the back presure would eventually push out the front seal. The pump is right behind the pump bushing.

The outer shaft is the stator and part of the pump body. It should be very solid. The center shaft is the input shaft and should not have much play. There is a bushing on the outer shaft to center the inner shaft. You may get a little play, but just enough for a lube film. Otherwise it needs a new bushing.

Replacing the pump/TC bushing, pump gasket, and large outer O-ring at this time would also be prudent. But it requires remove of the pump assy, and separation of the pump halves.


[Modified by arrio76, 9:32 AM 8/2/2003]

dath

Okay, that makes much more sense. Sorry for the confusion, I'm just in a bit over my head with the transmission. I was planning to have a book on the trans before I got everything to this point, but it had some shipping issues... Anyhow, based on what you said, I think that the bushing on the outer shaft must be needing replacement. I get enough play that I can hear a noise in the pump and easily feel it, more than a tiny wiggle I would think it should have at most.

So if I take out the pump assembly to replace those parts, any idea if I could find them at a normal parts store? Also, what torque should the bolts be set to when replacing them? As for the bushing, is that something that I could easily replace, or does it need to be pressed in/out? If so, would it be more time and cost effective to just get a new pump? Looks like Summit sells a Hughes pump for $85 or so. I could probably get that locally as well I would think.

Big Fish

Dath, if it were me, I would pull the trans and get a pro to look at it. It would be an easy job with the engine out. I tried to rebuild mine myself, failed miserably, but that's me, maybe you would have better luck. Fitting that pump is a bit tricky, everything has to line up perfect, and some of those seals if installed backwards can cause the torque converter to fail (don't ask how I know this). Chances are your trans might be ready for a little freshening up anyway.

arrio76

Most local transmission shops should stock these parts and be willing to sell them to you. Just tell what you have and what you are doing and they should be able square you away on the seals and bushings. Some national chains may be unsympathetic and not sell retail parts. I have had better luck with with the localy owned hometown shops.

The same shop could drive the out the bushing and install the new ones for you for a nominal fee (or free if you and they are personable) Would take less then 5 minutes. Bring the pump with you, cleaned up and ready to show them what you need. The parts should be less than $10, and perhaps the same to remove and install the bushings.

The pump halves need to aligned with each other on reassembly. I use a couple large hose clamps connected together to form one large clamp to fit the circomferance of the pump. Line up the bolt holes then clamp down the band and torque the bolts.

The bolts the hold the halves together and the pump to the case are torqued to 18ft.lb.

I work at a trans shop and we get a do-it-youselfer at least once a month. Most times installing the bushing for them is free.



[Modified by arrio76, 9:59 AM 8/2/2003]