Is a 3-4 shift flare caused by the intermediate servo or the direct clutch?

[ranger7ltr]

I have been dealing with a 3-4 shift flare that I want to resolve before I kill the tranny...

Some background...Truck had 151xxx when I bought it and the maintenance on it was suspect...Replaced fluid/filter and drove it and found that 1-2 and 2-3 shifts are soft unless at WOT... 3-4 shift will flare depending on how I back off the throttle.. If I back off the shift will happen without slippage or flare but if I don't back off the engine will rev up then shift...When I dropped the pan there was nothing in it besides a little gray buildup on the magnet area...

I have a new vb from 800700 trans as well as new EPC, TCC, and shift solenoids and that is the next logical maintenance on this truck...The fluid doesn't smell burned but it has an odd solvent smell to it.. I am not inclined to flush this tranny but the next fluid/filter change will include an external filter and new B&M stacked plate cooler...

Am I missing something or should I look at a different solution?

BTW, this is a 1999 Explorer Sport with the ohv 4.0 liter/5R55E automatic...

 

[kjgces]

i think i have the same exact issue

hey, i was just about to search on this topic and the search found your post. i have been working on my 98 exp 5r55e 4.0 sohc and my trans is doing EXACTLY the same thing. i have done the vb route, A FEW TIMES, and it still acts as you posted. i have adjusted the bands, both a factory settings and tighter. i also, against all recommendations, increased the pressure on the epc solenoid. it made a big difference in shift firmness and quicknesss but only lasted a few days. i think that stupid computer "readjusted" its logic to bring the pressure back down. i would like to choke the stupid engineer that set up that computer. i have fiddled with every thing in the vb, even bought a second one since i thought the first one was sticking. the vb is a piece of junk in my book, no seals where they should be and alum sliding on close tolerance bores, just DOES NOT cut it. i am going to keep searching for some answers but i think you identified the issue perfectly. hopefully we will get some action on this post, good luck, kjgces. i even got ripped off for 912.00 for a "rebuild" trans i bought on ebay. if i find something i'll post back here.

 

[ranger7ltr]

Have you changed the o/d and intermediate servos yet?

I have read and seen that the 3-4 flare is caused by the intermediate servo but then I also have seen the direct clutch apply pressure[or lack thereof] is causing this...

I have adjusted the intermediate band and will probably tighten it another 1/4 turn past the 2 turn recommendation to see if that improves the 3-4 flare shift...

With this vehicle, I would not rule out a servo problem due to exhaust heat but I also would bet that there has been "some" additive dropped into the tranny to fix this problem as I am sure this 3-4 flare shift problem didn't start when I bought the truck...Unless the pan has more garbage in it than the last time I serviced it[3 months ago] I am going to do a fluid exchange to see if I can get the old fluid out of the transmission as it smells like

I know the tranny mainline pressures increase as the rpm increase and that does cause the 1-2 and 2-3 shifts to become quite firm and definite and under those conditions if I let off the throttle by 4000 rpm the 3-4 shift is actually quite firm and definite as well...I just hate forgetting to back off the throttle and having the tranny flare as 3-4 starts to happen...

I am still going to replace the EPC and other solenoids before I replace the valve body although I am going to look very closely for any gasket blow out and retorque the vb bolts as well...This is the area that I am thinking maybe I could cause more problems by retorquing the bolts instead of replacing the seperator plate/vb but I really don't want to introduce another variable that might make this issue worse...Except for the shift flare this tranny works great even with the soft part throttle shifts and I don't want to grenade it if possible...

As always I appreciate any feedback on my line of reasoning...

 

[kjgces]

servos

yep, i did the servos and the sep plate, i found that if i torqued the bolts using my wrench i saw not comfortable with the feel of the wrench,,, what i mean is i had to use a wider setting between the second and last round of torqueing. if it set it to 90 then 97, it felt like it wasnt increasing the torque at all on the 97 setting so i used "wider" numbers to make sure i was getting the correct torque. i changed the servos with new ones, same size as the originals. i also have played with the band adjustments and found that going less than the factory setting improved the shifting but didnt seem to correct it all the time. i'm assuming the difference in performance during heavy throttle is based on better(more pressure, more volume) oil to drive the components. i tried increasing the solenoid pressure screw, but , i think the computer just adjusted the process back to its defaults. i was thinking slipping direct clutch as well but i'm not going to go in there to do anything about it. maybe there is another way of getting better pressure with an old trans like mine, 165K miles.

 

[ranger7ltr]

Another question...

Is your reverse slow to engage but drive is quick? I probably need to replace the reverse/low servo o-rings as a wear/maintenance item and see if the reverse engages sooner...

The delay is 4-5 secs for reverse vs immediate engage for drive...

 

[kjgces]

reverse and drive

my reverse WAS slow at first, now it is worse, actually clunks and acts like it is not STAYING in reverse. it wil move backward a little then slip out , then clunk back in for a foot or so and so on. after the first removal of the valve body, i replaced the orings on the reverse servo with the "d" rings, WATCH out if you do that, i put the smaller ring on and it was twisted..that made the reverse delay WAAY long, but , it worked perfectly once it was engaged...on the last valve body removal i put in the "double lip " seals, replacing the "d" rings. and now it works quicker but doesnt stay completely engaged. i found some data in the net about pressures in different gears and i think i still have a pressure problem, which is what leads to all this MESS in the first place. that stupid cheap design of a separator plate and gasket, not to mention the lack of and seals on a hydraulic circuit. how did they ever expect this to work for a long term. since autos are to be "out of fashion" in a few years and the people NEED to be in fashion, they don't make them to last longer than that. all in all i guess it is the consumers fault for letting them make this junk... i have a spare valve body, i might go the whole route and install all the goodies and see if that REALLY fixes this thing,,,end bore seals, boost valve, you name it whatever i can jam in there....