904 slow shifting into high gear????? Help plz!

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BigStrok3

BigStrok3

Mopar!
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I have a 904 Behind my 408 stroker. It seems to shift fine while at lower rpms. But when I run it up to say 5000 rpm it seems to slow shift only into high gear. The other gears seem fine. Since ive had this problem ive swapped out the clutches for high preformance clutches. Changed my shifter, changed the valve body, and changed my torque converter and still have the same problem. My setup is 904 with racing clutches I think there altco? Reverse manual cheetah valve body. It has the low first gear ratio. Any ideas or help is appreciated.
 
When you say slow, do you slow as in there's overlap or slow as in late? In other words when it does shift, does it still shift good and firm?
 
Almost like the pressure is bleeding down. Even when you first start it and put it in reverse it takes it a little bit to start moving.
 
sorry about that,just seen you have a T/A rev man unit,you may want to verify your adjustment on the front kick down band,sounds like a little flair up between 2-3 also make sure your throttle pressure linkage or rod is full open at WOT
 
throttle pressure liknkage is eliminated on a manual valve body, so that won't be it. I was gonna say somethin in the valve body.....but I dont think so. with the late goin into gear thing.....might be a converter problem. converter problems sometimes dont show up until in high or going into high under a load. I dont think it's in the valve body though.
 
good point strokerscamp no kickdown linkage,missed that one, I kinda know what your saying about the convertor,but I`ve not seen one only have a problem on the 2-3 upshift,I guess once it goes into 3rd its ok,it just sounds like it has a delayed shift,or did I miss that too? if it is a delayed shift,and we know the trans was air tested on the bench,cause everyone does that,right,no major leaks from the front clutch seals,than it could still be a front band adjust,I talked to Paul at T/A a few years back on a similar issue,it had the full manual forward pattern and it had a 2-3 flair up of about 600 rpms,he discussed how I was adjusting the bands,I said same way I`ve done them for the last 25 yrs,long story short he got me to tighten the front band adjustment more than I like to... and it took 300 rpms of that flair out of the shift,I didn`t dare go any tighter,didn`t want the band to drag,but remember that was a forward pattern,I mean it could be in the convertor,but do you concur we should check the seals and band adjustment first?Scot.
 
I dont see it being in the converter this is the second converter ive had in it and its done it with both. It sounds like im just going to have to pull it and go threw and change all the seals. I didnt air test this one it was bought off a guy that had it redone at a transmission shop. The thing is it was rebuilt probably 15 years ago and never put in untill a year ago.
 
been sitting 15 yrs...the seals all dried up and got hard.

you might try a bottle of that Lucas transmission seal ....it says on the bottle..."It really works"...lol
 
When you say it slips... Do the rpms rise before it "hits" into third?
 
Ive got some transx in it right now with no prevail. It will be coming out here soon. This will be the second time ive had it out in a month lol. Ive never really noticed the rpms jump while shifting into third so if it does its not much.
 
If you can, get some pressure readings. What did the high gear steels look like when they were swapped?
 
Since you changed all the other parts there's not much left but those 15 year old seals. When you take the valve body out look and see if it has a restrictor driven into the case port for the front clutch feed. Maybe someone had a shift kit in it before (many shift kits use a restrictor in the front clutch feed port) and it's not supposed to be there for the manual VB. That would slow down the fluid flow to the front clutch pack possibly causing the soft shift.

The slow engaging into gear when cold is common with a Mopar and is generally no sign of a problem. Most Mopars do it cause the converter drains back when it sits due to the manual valve exhausting in park. I always start mine in neutral to fill the converter up faster. Remember no fluid flows in park on a Mopar unless it has been modified.
 
Actually, I was going to say look two places ifthe cultches or steels had heat marks. First, the high gear servo piston and rod. This is a pressure loss point that can be repaired with the new billet servo, or a really good condition used/NOS (low mileage is the only ones that wont be worn). The second is the front clutch retainer that has the factory single wound clutch piston spring. Replace the drum with a billet steel and use the 727 style return spring setup.
 
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