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Discussion Starter #1
I have owned Mustangs with 5 speed trannys for 15 years now and have liked working on them whether fixing or upgrading.
I just bought this 95 LX Tbird with only 60K miles and plan to use it as a commuter car....am resisting the urge to start major upgrading projects because of limited time and also just want a fun stock car for commuting.
Anyway, I have driven a variety of cars and trucks with auto trannys but have not been around a 4R70W. I have already noticed wierd stuff and have since found solutions to most everything thanks to this awesome website. Not knowing the history of the car I know I will flush and replace with Mercon V (not sure if TSBs were ever done), will do 96+ sump (yes, it sometimes slips when cold), but I am debating how much of the J-mod to do, which brings me to the question of whether this thing is acting normal or not.
The 1-2 shift is VERY firm compared to aanything else I've driven. Anything more than 1/4 throttle gives everyone in the car a good neck jolt. 3/4 to WOT 1-2 shift is a huge and hard lunge but what worries me is I also get a bang/crunch noise that I have never heard in any other tranny under hard acceleration. No tire chirping, it is almost like the crunching sound that worn struts make when going over speed bumps in cold waether. Dont know how else to describe it.
What also puzzles me is that when i get on the gas and back out of it to avoid the crunch it hangs for like a half second (seems like forever) before shifting. Any other car I have driven upshifts quickly if you cut back on throttle.

So I am wondering if this is normal. People talk about firmer, harder, quicker, shifts after doing the 1-2 accumulator, different variations of springs, and J-mod, but I am not sure I want anything harder than what it is doing now. The 2-3 shift seems normal and 3-4 is more sluggish but seems ok so I don't know if I should drop the valve body and do more if I just want stock performance for daily driving.

Is this what they all do? Suggestions?

Thx,
Dzee
 

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Dzee,

Welcome to TCCoA! :)

Your shifting problem more than likely is a broken spring for the 1-2 accumulator piston. The 94-95 only had a lower spring and it has a history of breaking. Perfect opportunity to do a J-Mod and update to the newer style pistons.

You mentioned updating the tranny pan and filter so you may as well get it done! :D

Joe
 

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I did not get chirps until I put in a an upgraded trans from a shop in TX. I had the same bang sound until I up graded my IRS bushings. The old ones fell apart as I pulled them out.
 

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Discussion Starter #5
Thanks for the info.
I had planned on the 1-2 accumulator but didn't want it shifting any harder. I have read alot about springs, no springs, different colors, etc. I have watched videos and see different approaches....but if I basically want a stock setup what springs do I use for the 1-2 and also the 2-3?

Funderbird, so the noise was bushings? If so which ones? That is kind of what the noise could be...
 

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1-2 Top Spring F75Z-7F284-AA Light Blue
1-2 Bottom Spring F7AZ-7F284-BA Violet

No spring for the 2-3 piston.

Joe
 

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I do have a 1997 Valve body for sale (Upgrade from your 95). It has the middle Jmod in it, with a few sonnax upgrade pieces. PM me if you're interested. Heck, i'll sell you the deep sump pan too.
 

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1-2 harsh shifting is indicative of a broken 1-2 shift accumulator spring. It's the floating gears that is a bad sign, could be as simple as a worn tps sensor, mlps (range sensor), or low fluid. On the more serious side it could need rebuilding. If your looking for firm non harsh shifts I would perform the jmod retaining both springs for the 1-2, change the fluid to mercon V, switch to the 96/97 pan and filter and test or replace the tps and range sensor.
 

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Discussion Starter #9
Good point about the sensors, I didn't think about the inputs the computer needs to decide when to shift.
Fluid level is good, smells fine, but I have no idea what it is or how old it is.

Daniel,
I will PM you on your valve body and pan.


Thanks all for the info this far!
 

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If you get on the gas hard, then let off, the computer has already commanded a WOT shift, so that is what the delay is. That is normal for the stock program.

The opposite happens if you take it easy in a gear then suddenly punch it, it will shift too early.

The only way to avoid it is to stick with the original plan in each gear, no extreme changes in throttle %.

Al
 

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This is what mine USED to do. If I let off the throttle in second before it shifted to third then it would freewheel.
I replaced the 2-3 accumulator, removed the spring (also removed both from the 1-2 accumulator and replaced it) and replaced a number of the valves in the valve body with Sonnax parts, including the boost valve, main pressure regulator valve.

this is after doing that work:

Part throttle wasn't very good either before, but after it was where it should be.
 

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Discussion Starter #12
Thanks for the vids.
Mine seems similar to the second one, except the 1-2 is much much more abrupt... more like a lunge...but no chirping....
When I get this fixed I'll try to do some footage.
 

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What is freewheeling? The First video is spot on what my car does.
Free wheeling is when a clutch/band disengages without another reengaing immediately. The engine will flare, or free rev, until the next clutch/band grabs.
 

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Yes, I guess it is a flare, but to me a flare is brief. With mine the engine was allowed to rev freely for quite awhile before third then OD was engaged. Once the transmission shifted to third you can see the RPMs go from 5000 to 2500.

As far as harshness of shifts, I was after a hard WOT 1-2 and 2-3 shift. It is basically mild mannered at part throttle and only when very slick do I have to watch it, but at WOT hold on, the car had better be pointed straight ahead. If I leave traction control on, every 1-2 shift it engages.

I rarely shift not at WOT. No one else drives the car (my wife has driven it a total of 100 miles), so it is driven very aggressively most of the time.
 

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Discussion Starter #16
Here is my report out. I think I am almost there.
As Chris and Rodeo Joe said my harsh 1-2 shift was caused by a broken 1-2 spring. Actually it was broken in two places and was jammed together.
So after finding that problem I decided to not drop the valve body, yet. I did put a drain plug in the pan so it will be much easier to pull off in the future.
I ended up doing the 96 deep sump pan/filter, mercon V including draining the TC and radiator passages (12 qts total) and 1-2 springs.

The shudder is gone, it no longer slips when cold and turning corners, and the whole tranny seems to be performing better overall. So I am pretty happy.
What still needs tweeking is the 1-2 shift. I figured the harsh 1-2 was all due to the broken spring so I thought i would put springs in to give me a firmer shift than stock. Pre-96 T-bird trannys don't have a top spring in stock setup so I tried to average out all the multiple suggestions on what to do for a firmer 1-2 shift. I ended up going with a white top and purple bottom spring. Now it seems it went all the way from way too hard with the broken spring to a slow and soft shift now. It is pretty normal under light throttle but anything more than 1/2 throttle and it kind of "slides" into second. Nowhere near to a firm shift...not even a solid drop.....it seems like it just kind of drifts down into the next gear. Does not feel like it is slipping, just too slow.

So I am wondering if there is a reason why for 1995 the only cars that got the white/purple springs were the Crown Vics and Lincolns. The 1995 Stangs and T-birds use no top spring. I almost think that if I used only a purple bottom spring (which is what Ford specs) the 1-2 would get firmer.
Any thoughts?
 

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You could try the light blue top spring and leave it at that. If you want to pick up the shifts I think you'll have to drill the plate out.

Joe
 

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Discussion Starter #18
Top or bottom for the lite blue spring? I have that color and also a dark blue. Now that i think about it i didn't pay attention to the top and bottom springs to see if they are interchangeable.
 

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As an FYI, the purple bottom spring that is available now will make these things shift dead soft. It is not the violet spring that Jerry called for in his article. Ford discontinued those a while back. The purple spring is much stiffer and not what anyone wanting former shifts is after.

D
 
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