A904 flaring big time

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Woods74

Woods74

Broke Senior
Joined
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Hey all, I've got a pretty serious problem with my a904 I built myself. Its the last issue that keeps me from rolling my project I'm very proud of.

Let me start off with my gear:

Healthy magnum 360 w/ Indy X heads
Lokar Kick-down cable
2500 stall
Transtar rebuild kit
TF2 Kit
5 Clutch forward drum

Oil cushioned intermediate piston for kick-down band is blocked
No blocker rod on the 1-2 accumulator, spring in place.


Clutch pack clearance:

rear .040
front .080
gear train end play .010
input shaft .027

I am having similar problems to bobscuda67 In his epic post 'I HATE MY 904'.

The difference is: 1st has always been solid, 2nd is somewhat solid, it has slipped a time or two, the 2-3 has never shifted right. Even if I rev it all the way up, no dice. Until I let off the gas, then the shift to 3 is way lazy, on the downswing, thinking its in gear, I hit the gas then it does nothing but slip, catching momentarily at about 3-3.5k. Then slipping some more.

I tried to keep the slipping driving to a minimum, although some can't be avoided. I drove it around for an hour or so, I tried the spectrum of TV cable positions, and I even took it up to 4-5k and rode it hard once to see if the shift points changed. Not really. All I got was more slipping from 2 and 3 then and afterwards. Getting worse the more I drove it.

To top it off, I found out it was 2/3rd of a qt over full, drained it a little, firmer shift, and now I don't have 2nd.


I really don't want to rebuild it again..... I want this thing to chirp 1, 2, and 3 like its suppose to. I want the crap scared out of me! I want to feel the brute force of my labor times triplicate!... Get what I'm saying?

I'm a pretty patient person, but this elusive transmission issues I'm having makes me want to put in a manual, or a manual VB.


Or roll the car off a cliff...... My Brain hurts.


So, tomorrow, or 50 years from now, Im going to:

* Adjust Kick-down band and drive it see if it solves,
* Check Line pressure
* Take off the pan and inspect fluid,
* take the valve body apart, make sure its all good.

How much crap in the pan = a rebuild?

Any other suggestions, greatly appreciated. :faroah:
 
Clearances all look good.

By your description I doubt the throttle pressure linkage is the problem because once it gets in gear low throttle pressure won't cause it to slip. For future reference when you adjust the throttle pressure tighter (when a Lokar cable setup is pulled to the maximum at wide open throttle) that gives more pressure to the clutch packs and servo's so it'll tend to slip less between shifts.

Sounds to me like a bad seal in the front clutch pack or a bad/broken sealing ring on the reaction shaft. If you drop the valve body and do the air pressure tests it should give you an idea.

You mentioned it's getting worse the more you drive it. Hate to tell ya but the front clutches (maybe more?) are probably smoked. Doesn't take much slipping to smoke them.

It wouldn't hurt to run a line pressure test just to see what it is before you pull it apart.
 
Alright thanks for the heads up. I didn't bother with a line pressure test because I found the silver paint on my dipstick, felt pretty low, and didn't want to mess with it. I dropped the pan, drained it, tons of sludge. Proceeded to ordered replacement paper and rubber for it. Then tossed parts over my shoulder taking it out. I swear I'll be able to do this blind folded soon.

The only thing I can think of why 3 wont shift, besides what you mentioned, is the transtar kit came with a thicker inner lip seal on the direct drum, touting a better seal. So I installed it, never air check it. So much for taking it for granted. I'll post the results next week so the next guy can avoid all this.

Thanks!
 
There are actually 2 different lip seals for the front drum cause it changed in 70 (or was it 71??). Before that it had a wider seal. After 70 the seal was narrower. Maybe you put a old style wide seal on a new style piston?? Hate to say it but I bet all that sludge is friction material from the front clutch pack.

I always air pressure test them after the clutch pack is assembled and after everything is installed in the case. With the 70 and up front drum the oil port is a long machined area so it's impossible to test the clutch pack by itself so what you have to do is install the sealing rings on the front pump reaction shaft and slide the front clutch carrier down onto it and apply air to the hole on hole in the reaction shaft that leads to the front clutch. I even stack both clutch packs at the same time and test them both. You also have to use something to hold the clutch packs down on the reaction shaft as the air pressure will tend to want to make it take off.
 
Hey thanks for your ancient Chinese wisdom on the subject. I don't want to ask how many transmissions, and time, you put in to learn this knowledge.

:downtown:

Thanks for the faith, have a great weekend.
 
I feel your pain....I'm having very similar issues. My slipping occurrs in 2nd gear. Pulling my pan off today. Expecting issue with kickdown band and or front clutch. Probably end up pulling the thing out once again....lol
 
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