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 Post subject: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 3:27 am 
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4 BBL ''Hyper-Pak''
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Joined: Thu Sep 10, 2015 2:37 am
Posts: 44
Location: Kingman, AZ
Car Model: 1973&84 Sportsman,1987&88 D150
Rebuilt a904, used Toms book, only thing wrong was cracked torque converter hub. Decided to put deluxe kit and shift kit in while I had it out and open along with new torque converter. Take off in 1st or drive, works great! goes to shift to second, huge slip almost like its in neutral. Pulled trans back out, burned all clutches in first clutch pack (the 1st one that comes out or as I understand it, the one for 3rd gear). Took out 4, put 4 in when I rebuilt it. took to local trans guy who is really helpful, he said not enough disks, he put 5 frictions and steels in it, checked clearance with eyeball and said put it in. re cleaned everything, put it in. take off in drive, 1st ok, shifts too second, think I have been victorious, starting to swell with pride, then I take it out to main street to see if it goes to third and I'll bee dammed if it didn't almost throw me through the windshield! felt like someone slammed on the breaks. I kwik shifted to Neutral and costed onto a side street. Before it stopped, I put it in manual 1st and it went right into gear, but second was gone again. All air test worked perfectly and I swear, I put that thing together like it was made of glass. Little labeled baggies, big table to lay it all out in order. measured everything a thousand times with a caliper. I'm gonna tear it down again tomorrow for the third time, pretty sure I know what I'm gonna find. Trans guy said bring it by after hours and he would help me, but that kind of feels like giving up!!!! Ordered ATSG , maybe that will help with some of the finer things that I was questioning in Toms book. Real easy to mix up some of the 727 and 904 stuff if you get distracted and it seems like there are a few changes in the later years that I can't find photos of or diagrams that exactly match.

If this sounds familiar or anyone wants to chime in, please and thank you!!!!

1987 dodge d150, a904, all original including carb and smog, with 66,000 original miles, last year of the /6!!!

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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 5:21 am 
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EFI Slant 6

Joined: Mon May 26, 2014 4:02 pm
Posts: 430
Location: Vermont
Car Model: Slant Six M37
I've never installed a shift kit... But I am wondering if the valve body-shift kit is working one set of clutches against the other?


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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 7:30 am 
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Supercharged
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Joined: Wed Oct 12, 2005 9:00 pm
Posts: 2908
Location: kankakee IL
Car Model: 80 volare, 78 fury 2 dr, 85 D150
there are more than 1 shift kit, some will or wont work with lockup trans, you can build it up for towing/hauling or neck snapping for non street 1/4 mile race.
I have never had much luck with 904s anyway, they dont seem to last/hold up in regular normal everyday street driving. For me anyway.
the 727 is very much the same design, except for larger diameter clutch drums, shafts, etc..... Ive been inside both of them over the years.
Not enough to eyeball clearances and such, still measure clutch pack clearances and such with feeler gauges and count threads on band adjustments while I watch others do those same adjustments by eyeball/ these guys have built more of them than me.
Your original problem, "neutraling out" between gears sounds like a pinched piston seal in a clutch pack (Ive been there, very aggravating to get it all together and back in and find out it aint working) or possibly something with the front band servo (front band works for 2nd, has to release "cleanly" for it to hit 3rd.)
on the slamming into gear Ive often had that when a trans is dying, clutches are worn (or too loose free pack clearance, where your guy added teh 5th disc) and the clutch piston has a long way to go (relatively) to squeeze the clutch pack to apply.

How many springs did you put in within the clutch pack that has the little springs "standing up" under the piston? The factory service manual had a chart in it, to determine how many to use for different applications.
also when I did my last trans ('99 42RE out of my Dakota) I bought the ATSG book to try one out, compared to what I have used in the past. Alot of copy from factory service manual within. That trans started doing the "neutral out" between 2nd and 3rd, as it turns out that was common those years, something with how they machined the clutch piston from new, the kit I got came with "updated" piston seals and there was an info sheet within the kit to illustrate the change.

As far as shift kits.... often they give you a different separator plate for the valve body, and/or they tell you to drill certain passages in the old plate, leave check balls out, etc. Its easy to drill the wrong hole (there are so many) or drill one just a little too far, which will have a huge effect on how it turns out.
sometimes they give you a "blocker rod" to hold off the accumulator which will harden up shifts. especially (as I remember), the 2nd to 3rd shift.
When I did my 1st shift kit about 30 years ago, I went to Super Shops and bought a B&M shift kit for my 75 Cordoba. of all cars haha.... They had a "heavy duty" and a "competition" option on how to install/ which sheet to follow/parts to use within. I went with the "competition" one the 1st time, and I regretted it. In a turd of a car with a 318 and 2.76 gears (hey I was like 20 at the time) it would snap my neck and bark 2nd gear every time Id take off even when I wasnt trying.... I remember when my Mom would borrow my car, (which wasn't often after she experienced that) it would scare the He11 out of her and she has always driven like a 90 year old since I can remember..... but I learned by what I did there.
I don't do that many trannys any more, but in just about every one I do, I put in a Gil Younger Transgo kit and when driven, it doesn't act much different than stock. it does firm up the 2-3 shift "a little". but nothing like that B&M kit I did in the late 80s. and it does make a difference in longevity and such... I havent done a 3 speed (904/727) in even more years, mostly A500/518 style trannys. In those I use a TF-ODjr kit. They make a comparable one for the 904/727.

In fact when I did that trans in my Dakota earlier this year (10000 miles ago already!) I hadnt done one in a while and I put that clutch pack together 2x and thought sure I had pinched the lip seals upon assembly (after the 1st one you do that to, you "know it" as soon as you put it together even before you put it back in the trans) I got "gun shy" and took that clutch pack to the local Mr Transmission shop and let them out that piston and seals in for me.... even though I have done that particular task probably 25 times over the years.... so far its still doing great. On this one instead of the shift kit I put in billet accumulator, a billet front servo, (they have double teh number of seal rings on them to help insure they wont leak fluid/pressure, and they sure aren't plastic) to "improve durability" -- hopefully. I went in there mostly to replace the front band as I thought that was where my "neutral out" between gears might have been. The band did have a few chunks out of it so it would not have been long and it would have definitely been a problem... it certainly won't be now. In the newer (mostly OD) trannys that front band does seem to be an issue more often than on the old 3 speeds. thats why I figured Id better beef it up with the new servo with 4 seal rings instead of 2, "while I had it apart".
many of these parts are the exact same between 904/727 and the OD versions.


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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 12:06 pm 
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Supercharged
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Joined: Sat Nov 27, 2004 8:03 pm
Posts: 9551
Location: IRWIN PA
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I have a lockup slant 6 727 for sale if you wish to go that route.
http://www.slantsix.org/forum/viewtopic.php?f=8&t=65271

I disagree with don in this regard.. 904's can be built skookum as frig.

Some small block guys build them and run them behind 9 second small blocks. Lighter rotating mass than the 727.


Greg

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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 1:42 pm 
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4 BBL ''Hyper-Pak''
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Joined: Thu Sep 10, 2015 2:37 am
Posts: 44
Location: Kingman, AZ
Car Model: 1973&84 Sportsman,1987&88 D150
volaredon, Thank you for taking the time to help. Wouldn't a pinched seal show up while air testing? I have had every seal in and out a dozen times checking for that very thing and have yet to see one pinched or folded back.

Nothing is worn or dying, its all new except hard parts which I have measured at least twice. Its not exactly neutraling out, if you step on it hard enough, you can feel it like a rubber band trying to pull the truck forward. It has never slammed into gear. It just felt like someone applied the brakes very hard, very quickly and now its back to "slipping, rubber banding, hard to describe" condition.

There are no little springs under the clutch pack with the problem, and I cant remember how many are in the other clutch pack, I can tell you that what was there was cleaned, inspected and returned just like it came out.

Shift kit is a trans go TF SC. It says one of the things it fixes is "lockup shudder" on the box. I followed instructions to the t, and only installed it with the standard upgrades recommended for daily use. The main reason for the kit was "Pump bushing/seal burn up while in park" problem that started this whole thing. I did enlarge a hole in the separator plate, but only after checking it a hundred times, scared to death to mess it up. Marked with sharpy and used the exact size bit as instructed.

The valve body is the part I am most uncertain about! I have taken it apart half a dozen times trying to compare to diagrams i can find on line. I have not found a diagram that exactly matches every piece of my VB. That is where some subtle differences are giving me doubt. I did every air test I could while grandson turned the input shaft. everything worked perfectly, both clutches "thumped", both servos applied smartly, output shaft turned the right directions. The couple shifts I got last night where smooth from 1st to 2nd, I think something with VB caused the 3rd gear to shift incorrectly, and the result destroyed second in the fight..... like you said about the kick down band not releasing.... or like Jase said about "clutches" working against each other.

I have one more thing to add, last night before the road test. I had the truck off the ground, going through gears, topping off fluids, listening, checking for leaks. I had it all ready to go, so I increased rpm a little and manually shifted from 1st to 2nd, it shifted nicely and wheel speed increased. I shifted to 3rd and noticed that wheel speed would slow and increase in a kind of cycle? I think maybe it was shifting back and forth between 1st and 2nd and never really going to 3rd. you could hear the engine work harder as it changed to the slower wheel speed. That might be the key to solving this!

Thank you!!!!

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Crazy Dodges are killing me and I like it!


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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 1:47 pm 
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4 BBL ''Hyper-Pak''
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Joined: Thu Sep 10, 2015 2:37 am
Posts: 44
Location: Kingman, AZ
Car Model: 1973&84 Sportsman,1987&88 D150
Greg, thanks for the offer. I have no doubt in A904s like you, and want to keep everything as original as possible. I know this is my fault, not the 904's. I have made a mistake somewhere and my inexperience is making diagnosis very hard. If I mess it up bad enough, It might have to take you up on your offer!!!!

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Crazy Dodges are killing me and I like it!


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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 1:50 pm 
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4 BBL ''Hyper-Pak''
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Joined: Thu Sep 10, 2015 2:37 am
Posts: 44
Location: Kingman, AZ
Car Model: 1973&84 Sportsman,1987&88 D150
Jase, I think you are right, but I don't know how to find the cause. I wish I could find a flow diagram for the VB, showing how each valve should be during each shift and gear, then check for a misalignment or something I put together wrong.

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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 2:04 pm 
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Joined: Thu Oct 31, 2002 5:39 pm
Posts: 24486
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Quote:
I have never had much luck with 904s anyway, they dont seem to last/hold up in regular normal everyday street driving.
Uhhhh…that makes one of you. The 904 has a well-deserved, legitimate reputation as a very durable and dependable transmission.

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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 3:06 pm 
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4 BBL ''Hyper-Pak''
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Joined: Thu Sep 10, 2015 2:37 am
Posts: 44
Location: Kingman, AZ
Car Model: 1973&84 Sportsman,1987&88 D150
I just remembered, I have a 1988 d150 in the back yard with a v6 and I think it has a 904! I'm going to pull it and use it for comparison. I'll tear it down and lay it out to look for differences. it should be pretty close other than the housing. Might even be able to steal something off it if needed.

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Crazy Dodges are killing me and I like it!


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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 5:27 pm 
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Joined: Thu Oct 31, 2002 5:39 pm
Posts: 24486
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Quote:
I just remembered, I have a 1988 d150 in the back yard with a v6 and I think it has a 904!
An '88 V6 D150 has an A998 (probably) or an A999 (possibly). Both of them are based on the A904, but they are not A904s, as such. You don't mention what year A904 you're working on, but be careful not to put too much weight on a comparison that might not be valid.

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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 5:39 pm 
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EFI Slant 6

Joined: Mon May 26, 2014 4:02 pm
Posts: 430
Location: Vermont
Car Model: Slant Six M37
Quote:
I just remembered, I have a 1988 d150 in the back yard with a v6 and I think it has a 904! I'm going to pull it and use it for comparison. I'll tear it down and lay it out to look for differences. it should be pretty close other than the housing. Might even be able to steal something off it if needed.
Take your time.. maybe even study your present valve body first, so you can notice any differences. Better yet, and in addition to that =>Take PICTURES of the Valve body... or diagram it as you are taking it apart.. as the notes will help you realize and remember what when where...

Kudos to you for taking on a tranny rebuild in the first place. You will get this figured out...


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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 7:26 pm 
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Turbo EFI

Joined: Sat Feb 18, 2006 2:19 pm
Posts: 1603
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lGo close to bottom of page Advantages and Disadvantages
https://www.allpar.com/mopar/performanc ... -mods.html


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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 8:06 pm 
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Supercharged
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Joined: Wed Oct 12, 2005 9:00 pm
Posts: 2908
Location: kankakee IL
Car Model: 80 volare, 78 fury 2 dr, 85 D150
Quote:
I have a lockup slant 6 727 for sale if you wish to go that route.
http://www.slantsix.org/forum/viewtopic.php?f=8&t=65271

I disagree with don in this regard.. 904's can be built skookum as frig.

Some small block guys build them and run them behind 9 second small blocks. Lighter rotating mass than the 727.


Greg
sure a 904/998/999 can be built up no doubt.... but as-sent down the assembly line, I just never seemed to have much luck with them......
IMHO they definitely didn't belong in a heavy B body or a truck or van behind a V8. in most A or F bodies (lighter car) I'd be OK with them..... other than the higher perf versions.
one 998 that I replaced with a 727 was in a B van that towed a camper, and a few 904s in B bodies (Cordobas etc) that I trashed 904s in that got 727s in their place. ....
others also put 904 guts in a 727 case for racing....

and yes tehre are differences in 998,999 vs the 904 but mostly related to the lower1st gear the "mechanics" of rebuilding either would be very much the same.
and no, the pinched seal don't always show up in an air test. How much PSI are you using to do your air tests?


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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 8:08 pm 
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4 BBL ''Hyper-Pak''
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Joined: Thu Sep 10, 2015 2:37 am
Posts: 44
Location: Kingman, AZ
Car Model: 1973&84 Sportsman,1987&88 D150
matv91, I read that article and it mentions overlap of 2nd and 3rd, timing and the braking effect. I think that might be the golden ticket. Thank You.

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 Post subject: Re: A904 kicking my ass!
PostPosted: Sat Sep 19, 2020 8:11 pm 
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4 BBL ''Hyper-Pak''
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Joined: Thu Sep 10, 2015 2:37 am
Posts: 44
Location: Kingman, AZ
Car Model: 1973&84 Sportsman,1987&88 D150
Slantsixdan, I put the specs for my project at the bottom of the original post. It is a 1987 d150 with a904 all original 66,000 miles. That 1988 is almost out and I hope it's a 904! Thank you.

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