Overdrive [or lack of] problem.

[95-stang]

I think the box is probably on its way [well something is] and it all started so easily, or not.
Every so often [as it seems others have found] occasionally when flooring it, the revs would bounce off the limiter, somedays it did it, some not, and often in different gears, but under normal load, no worries, i deduced the converter might not be locking up properly?
So i got new Mercon V, a Transgo shift kit, and a Sonnax kit, plus the EPC solenoid. I expected lots of shiny metallic looking stuff in the sump, but it was clean, so i stated fitting the kits, the solenoid, and also new 2nd and 3rd steel type accumulators, the Sonnax kit also had a modified overdrive servo pin to help prevent pressure loss there. I did find a broken 2nd accumulator spring, but i read thats not unusual, and the kit had new ones.
So i finished, dropped it down, drove it and when it got to about 40-50mph O\D on, the engine just revs up, no drive, unless you take your foot off and then back at 40-50 is there again. Switch off O\D and the car seems to drive normally, went upto 70, but did'nt go further as of course it was revving higher without O\D but it worked.
I have no idea whats gone tits-up, autos have always been a dark art to me, i'm a manual box man for years, i'm thinking overdrive band failure, but why did the problem change from occasional slip to no overdrive "overnight" as it was ok the day before?
I have taken the sump off to check i did the valve body ok, and it seems its spot on, just have to check the rest in daylight as its stuck outside atm and winters starting to bite.

 

[95-stang]

Done some digging, and this has to be it:

"When you remove the main controls, you will find a hole in the case next the OD servo bore. The hole goes through to the barrel of the transmission where you will see the OD band. If you remove the OD Servo and do not anchor or hold the OD band, it can move when you attempt to re-install the OD servo. If this occurs, you will not have access to the Overdrive gear (4th)."

Of course i put in a new pin, the instructions said bugger all about lining this up.

"Use the rooster comb p.n. 7E332, to wedge against the OD band. Install it into the hole next to the OD servo bore so that the roller is sticking out. Wedge it against the back of the OD band and the transmission case, but do not damage the Rooster Comb Spring."

Anyone ever done this [which i doubt] , looks like its poking around time again.

 

[95-stang]

All fixed and it was the above, [except i used a 25thou feeler to push the band up] cant believe Sonnax who suppy the overdrive servo pin in their kit, dont mention if your replacing in situ that the overdrive band will basically "fall down" and you can with a little work, push it back up and hold it till the pin engages.
So thats the Transgo kit installed anyway and that was straightforward, and if your doing one, watch the video, then more or less ignore the video [as they warn you its out of date] and follow the written instructions, which are'nt the best, but are enough to get the job done with.
I also fitted a new EPC [electronic pressure control] solenoid which also came with no instructions, again i managed to find some on the web, as neither Alldata or the Haynes\Chilton manual do much more than describe what an auto box does.
So if anyone needs any help regarding shift kits etc, please ask. :santa_smiley:
As the weathers been crappy i hope to test it this weekend, if there's any problems it can wait till summer for a new converter etc.

 

[Jrgunn5150]

Well... It was already flaring into 4th correct? Then you tried preventative measure's and lost 4th altogether?

You can try replacing the shift solenoids, but I beleive you were losing the band. When you attempted to fit the overdrive pin and didn't anchor the band, it probably lost contact altogether. I'm assuming the modified pin is slightly longer, which would hold the band with more force, as well as be a band-aid on a unit like your's that is heading out.

If you did drop the band, you can get at it by pulling the servo out, you need to reach through there with a screwdriver, or better yet, brass punch to finagle it back into place. Be careful not to mar anything. Once you get it back into place you can hold it there with the "rooster comb spring", while you re-install the OD servo, then you can reassemble with the spring and snap rings.

 

[Jrgunn5150]

I already typed all that, I wasn't losing it, lol. Glad you got it sorted.

 

[95-stang]

The original problem was [like a few others have had on here] very occasionally when you booted it, sometimes it would bounce off the limiter, other times not. I could'nt get Mercon when i first got the car, but i used Dexron 3 which was obviously better, as it got rid of the TC shudder, the recalls did'nt happen in Japan it seems. So this time i got Mercon V, a new filter and the other bits and pieces to see if i can eliminate the problem, or if a new box or converter is the way to go [or a box rebuild].
Everyone i have spoke to has given different reasons for this occasional "revving up" [or revving out] so my only choice was to try the simple stuff first, i found no real bad news [apart from the common broken spring] no burnt oil, although the car has 50k thats hardly astronomical mileage.
Thanks for the reply, i'm happy for any advice, i never touch auto boxes, and 99% of cars i work on are manual, i doubt i would bother with auto again, there's too fine a line between working properly or not at all.
I could'nt find a manual car when i was looking, everything was auto, and i cant be bothered swapping this one to manual, unless there was a breaker which would be rare here.

 

[Jrgunn5150]

If what you've already done doesn't fix the problem, pick up new shift solenoids.

The problem is that the AODE was just full of less than ideal part's, it could be several thing's, the only other good thing it could be short of a rebuild is the shift solenoids though.

 

[95-stang]

Thanks, its not a big job to whip off the sump and do them, in fact i feel like i'm doing them in my sleep.... :santa_smiley:
Anything that might cure it is worth a try.