904 shifting weird

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MileHighDart

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I've got a used 904 behind my 318.
I got the trans several years ago, it was pulled from running 74 Dart. And that's all I know about its history.
When I got it, I put in new front, rear, and selector shaft seals, a new pan gasket and filter, and filled her up with fresh fluid.

It's been working fine until a couple weeks ago. Seems to shift fine when its cold, but after it warms up good it starts acting weird. Like very delayed 2-3 shift. Its like driving around town, taking off from a light, it will shift perfectly fine one time, and the next time I will get the delayed 2-3 shift. And a couple times is has shifted down abruptly from 3-2 when decelerating.

Checked the fluid when I got home today, fluid is so clean you can hardly see it on the dipstick. But checked it 3 times to make sure. Checked when hot, idling in Park, it looks like the fluid is about 1" above the full mark.
Will too much fluid in the trans make it shift funny or do I have something more serious going on?
 
My unmodified 904 [dipstick] says check hot, idling in ..Neutral...
 
Idling in neutral is the way to check. As for the actual problem I'm not much of a transmission guy.
 
I re-checked it in Neutral, same thing. It looked a little over full.

This morning I put it on ramps and drained about 1/2 quart out of it.

When I first put this trans in I was smart enough to put a drain plug in the pan. Made it really easy to drain a little out.

Unfortunately this made no difference in the why the car shifts.

Took it out for a ride today to run some errands. Still very delayed up shift from 2-3 after its warmed up. Wont shift into 3rd unless I run the car up to about 55mph and let off, then it will shift. So running around town today I was stuck with 1st and 2nd.
Weird thing, it shifts fine when cold, but after it gets warmed up then I have problems.
Even when I stopped for lunch, about 20 min, it shifted fine for the first few minutes of driving and then would start acting up again after it got warmed up.

Got a little advice from a poster on another site, he said delayed upshifts, and the abrupt downshifts are usually caused by worn out governer seals. Does that sound right to anyone ?

Really don't want to pull the tranny for a rebuild right now, I've never had an automatic apart before, and I cant afford to pay someone else to rebuild it.
 
Sounds like kick down linkage needs adjusted,mine will do the same thing if kickdown cable is set too tight.Are you running a stock linkage or a cable setup?
 
midlife89 said:
Sounds like kick down linkage needs adjusted,mine will do the same thing if kickdown cable is set too tight.Are you running a stock linkage or a cable setup?
Click to expand...

Stock linkage, and its been working fine for a couple years, just started doing this about a week ago. Also when I was on my ride today, I stopped several times and backed off the adjustment on my kickdown linkage, backed off to the point that it will not kick down when you floor it. And it made no difference as far as the weird shifting. That was one of my first thoughts, that maybe I had it set to tight.
 
Does this trans. have a modified manual valve in it? If not there's no possible way it checks the same level fluid in park and neutral because in park it bypasses and neutral it charges the circuits so it'll always read a lot lower in neutral. The only case being if someone has installed a modified manual valve in the valve body to make it pump in park. After warm up or a drive I'd recheck after it's idled in neutral for a minute or two. My guess it's just low on fluid
 
Not modified in any way.

I should have said that after I drained 1/2 qt, and then rechecked second time in Neutral it was showing a little low.
So yea your probably right that it was reading high when I checked it in park. It probably was dead on full if I had checked in park the first time. So now it is a little low.
 
A little low shouldn't hurt. I'd start by running oil pressure checks and see how things look. The governor sends oil pressure to the shift valves in the valve body which are controlled by spring tension and if the pressure is low it won't build enough pressure to kick in the 2-3 shift valve in as fast as it should. I'd first look at the line pressure to see if it's up to snuff then if it's ok check the governor pressure. If you need instructions I have a couple pages from the factory serv manual scanned that I can post that shows the procedure for pressure testing

BTW: does reverse work fine? No slipping and kicks in as soon as you drop it in gear?
 
This sounds like a possible broken VB spring or contamination in the fluid hanging valves to me.
It seems to erratic to be something normal wrong.
(If you know what I mean by that :))
 
fishy68 said:
A little low shouldn't hurt. I'd start by running oil pressure checks and see how things look. The governor sends oil pressure to the shift valves in the valve body which are controlled by spring tension and if the pressure is low it won't build enough pressure to kick in the 2-3 shift valve in as fast as it should. I'd first look at the line pressure to see if it's up to snuff then if it's ok check the governor pressure. If you need instructions I have a couple pages from the factory serv manual scanned that I can post that shows the procedure for pressure testing

BTW: does reverse work fine? No slipping and kicks in as soon as you drop it in gear?
Click to expand...

If you could post those instructions that would be great, cause I wouldn't know where to start. Reverse works perfectly, no problems there.
 
TrailBeast said:
This sounds like a possible broken VB spring or contamination in the fluid hanging valves to me.
It seems to erratic to be something normal wrong.
(If you know what I mean by that :))
Click to expand...

Could be something like a broken spring. Cause it seemed to start doing this all of a sudden.
As for the fluid, it looks super clean on the dipstick, and the 1/2 quart that I drained out looks very clean as well. No visible contamination of any kind in the fluid.
 
MileHighDart said:
Could be something like a broken spring. Cause it seemed to start doing this all of a sudden.
As for the fluid, it looks super clean on the dipstick, and the 1/2 quart that I drained out looks very clean as well. No visible contamination of any kind in the fluid.
Click to expand...

If there was any contamination it will be on the bottom of the pan and normally would not come out with draining fluid, from my experience anyway. I have had a fully blown 3rd gear with all the clutches wore down to the steel in both the front and rear drums, bands were the same and when I drained the fluid it looked perfect. When I pulled the pan and took a peak all the material was on the bottom of the pan. I had to use a putty knife to scrape it all out.
 
Mad Dart said:
If there was any contamination it will be on the bottom of the pan and normally would not come out with draining fluid, from my experience anyway. I have had a fully blown 3rd gear with all the clutches wore down to the steel in both the front and rear drums, bands were the same and when I drained the fluid it looked perfect. When I pulled the pan and took a peak all the material was on the bottom of the pan. I had to use a putty knife to scrape it all out.
Click to expand...

I always hated doing one like that because of all the metal in every nook and cranny it could pack into.

You mentioned settling in the pan, and it does the same thing in the valvebody. (metal dust settles in the bottom of the valve bores)
 
MileHighDart said:
If you could post those instructions that would be great, cause I wouldn't know where to start. Reverse works perfectly, no problems there.
Click to expand...

Here ya go. This covers pressure testing. I have the complete ATSG service manual on PDF but it's too big to upload here. If you'd like is PM me your e-mail address and I'll e-mail it to you.
 

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TrailBeast said:
I always hated doing one like that because of all the metal in every nook and cranny it could pack into.

You mentioned settling in the pan, and it does the same thing in the valvebody. (metal dust settles in the bottom of the valve bores)
Click to expand...

I hear you... What's funny is when is the filter supposed to do its job? I guess it comes down to
Microns on the filter as too how much it will pick up.

The Trans I'm talking about is tore apart as a back up rebuild. I'll be putting it together
in the next couple months. I ended up rebuilding the spare 904 I had.

Thinking about putting some Indy 360-1's on the next motor so I may use the 727 I have ready for the task instead.
 
Tracy, I got to looking at what you sent me this morning. It filename says 904-A500 but when I open it, it looks like its a manual for the 42RE ?
 
I'm no tranny guy, but if you have to get it up around 55 to shift to 3rd, sounds like throttle pressure linkage.
 
MileHighDart said:
Tracy, I got to looking at what you sent me this morning. It filename says 904-A500 but when I open it, it looks like its a manual for the 42RE ?
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Sorry about that. I downloaded it a long time ago and never even looked at it because I have the manual. I just looked and see someone named it wrong. It is just for the A500 (42RE). I see Louis found what you need and that's good
 
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