I'm stumped. Challenge for tranny experts: Toyota transmission (A140E) slipping in 2nd gear in 'D' and '2' position.

Tranny experts,

I have investigated so many things and now I'm wondering what you tranny experts think could be causing the problem.

The problem is 2nd gear slips in [D] and (slightly less) in [2].. Also

2-3 shift is sometimes delayed and harsh.

This is a 93 camry 4 cylinder w/ 60kmi on a rebuilt A140e tranny.

If anyone has a good suggestion I'll post my result of the fix/test.

fwiw, here are my notes:

Shift feel

----------

1-2: a) normal bump/flair when shifting but 2nd slips. b) sometimes there's the normal bump, then it seems somewhat in second, then about 1 second later there's a second more noticeable 'bump' and it seems it is slipping much more now. This happens in [D], not sure about [2]. 2-3: sometimes delayed and harsh, especially if forced by letting off gas abruptly. 3-4: perfect 4-3: perfect 2-1: perfect 4-4lockup:perfect

Shifts all seem to occur at reasonable speed/throttle. Shifting w/ manual lever works like above.

Gear feel

---------

1,3,4,4locked: perfect, no slipping when given lots of torque, etc.

2 in [D]: slips w/ any throttle, very light throttle will allow enough slow acceleration to eventually get into 3rd.

2 in [2]: Less slipping--Seems to not slip too much if using less than 1/4 throttle. Engine breaking feel seems minimal. Engine speed seems (only roughly) related to wheel speed (due to slipping?).

2 going from [D] to [2]: Can't hear/feel one-way deactivating or break activating. seems to slip slightly less in "2 in [2]". Is one-way clutch engaged in both? Maybe air test the break on 2nd's one-way clutch?

The first day it did this it seemed to happen after warming up and while turning. After tests and extensive road tests 2nd seems to slip when cold too.

Tests

----- Torque Converter Stall: passed. (2450RPM at R and D) Engagement delay test : passed. (N-R < 2 seconds, N-D < 1 seconds.)

Electrical system : passed. Sol1, Sol2, SolL signals from ECM are good. Solenoids : passed. Resistance good. 70psi shop air causes only small leaking at 0V, air rushes with 13V. DTC : "Code 63--Sol 2 failed" existed when starting debug, but the sols were tested above to be good. Throttle cable : passed. Seems 'taught', +1mm and -1mm adjustment didn't seem to impact slipping 2nd. Hydrolic : pending.

Flushed full 7qt Fluid: No effect. Original fluid was dark but still smelled good. No hint of burnt. Valve Body : Rebuilt it. Looked clean, all balls, seals, gaskets, valves seemed superficially ok. Paid particular attention to

1-2 Valve. Didn't measure spring tensions. Rebuild didn't seem to affect 2nd gear slipping.

--------- What do you guys think could cause this slipping? Anything new I should check? Anything I checked that I should re-check?

Reply to
eekthorp
Loading thread data ...

Rebuilt tranny after only 60,000 miles?

Why so soon? (Are you the 2nd owner?)

Reply to
mrdarrett

Does the lever on the transmission move as soon as the throttle starts to move?

Reply to
Alan

You sound like an expert yourself doing all those tests. I don't know much about these trannys, but just wondering if a marginal #2 shift solenoid can cause problems that may seem like problms in the #2 brake or the #1 one-way clutch, such as leaking line pressure. Or it may be leaking from a seal some where.

2 to 3rd harsh is usually attributed to the accumulator. Of course, clogged strainer can do that but it will show up in all the gears.

Fill us in when you find the problem. A friend had a slipping OD in a

  1. He had to rebuild the tranny, but most of us wouldn't know other than AAMCO.

eekthorp wrote:

Reply to
johngdole

Heh.

Reply to
Gary L. Burnore

Alan, Yes (unfortunately?), the throttle, cables, and lever in the trans all seem to move togeather nicely.

-- eekthorp

Reply to
eekthorp

You are probably leaking fluid pressure at your second brake piston, which will cause flare-up in 2nd gear and eventual friction disc wear out. It's difficult to test short of tear down and inspection, because Toyota only gives you a main line pressure port. You can tap a gauge in here and compare line pressure in all gears, then look for a small drop in second when the vehicle is actively slipping.

Toyota MDT in MO

Reply to
Comboverfish

Heh, thanks for the complement. Based on your comments it sounds like you've been doing this much longer than me.

Does anyone have any suggestions on how to rule out "low #2 break pressure", "poor 1-2 valve position", or "partially opening #2 Sol"?

It seems theoretically possible that #2 Sol not opening enough (whatever that means) could cause the 1-2 shift valve to barely open causing reduced pressure to the #2 brake or #1 one-way clutch, which may only affect 2nd gear. Maybe someone more familiar can comment if this type of thing actually happens in practice.

Strainers/filter all looked pristine when I rebuilt the valve body. Bottom of pan was also fairly clean, but unfortunately there were no magnets in the bottom.

-- eekthorp

Reply to
eekthorp

Does this mean that B2 and the one-way stays active in both 2 in [D] and 2 in [2]?

Do you feel it would be worthwhile to take the valve body off and test the piston for leaks with shop air before teardown and inspection?

None of my shop manuals cover replacing pistons. If you know off the top of your head, is ordering a Toyota shop manual RM322 the recommended one for overhaul? It would be nice if it also has a diagram w/ labeled piston input ports and a full hydraulic schematic.

-- Thanks, eekthorp

Reply to
eekthorp

Second Brake (B2) works along with the #1 one-way clutch (F1) to hold spinning components in second gear range. B2 is hydraulically activated in [Drive] 2nd and [Manual] 2nd. F1 grabs on acceleration in [Drive] 2nd and freewheels on decel. F1 is not truly used in [Manual]

2nd because B1 (the one band in the tranny) is hydraulically activated to keep the trans in 2nd gear engine braking mode.

Slipping is not likely caused by any of the three accumulators in the case.

Our online version for the A140E is labelled RM322U, so I guess the RM322 is the paperback version. You won't find hydraulic schematics in any of the repair manuals. RM322 offers a description of the unit, powerflow diagrams, then complete component disassembly. The regular repair manual covers basic on-car diagnostics and unit removal.

P.S.

I still think your B2 piston is leaking. If you are slipping in [D]2nd more than [M]2nd, it could be that the B1 band is slipping also, but still offering some grabbing force. B1 is just a light duty band. It is not anchored or designed very sturdily, as it's true intention is to keep your engine from flaring down to idle during [M]2nd deceleration. It is probably strong enough to hold for a while, but continued use of it on a trans whose B2 was slipping would cause it to glaze/wear pretty fast.

I don't hold the F1 as a likely cause of slippage. It is a metal roller type one-way clutch, that if it were slipping, would be due to metal fragmentation. There would be an accompanying noise when it slipped along with metal in the pan.

Toyota MDT in MO

Reply to
Comboverfish

Thanks Comboverfish. That's good information on this problem, even for those of us who don't have it.

Since tranny is considered the most sophisticated component in a car, what do you think for those of us who can disassemble/assemble engines to try to fix our own trannys? Such as replacing B2 piston, brake bands, etc.

Does the RM322 provide enough information for a backyard mechanic to do a complete tear down and rebuild?

Is there a rebuild kit for the A140E?

Comboverfish wrote:

Reply to
johngdole

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.