Please Help A4LD

[mat89RS]

Hi,
in Drive my X has a rev limiter of 4000rpm for unknown reasons, in neutral, it goes well over 5000.


My tranny won't shift at WOT since I can't reach the proper RPM.


anybody knowns why it would be doing that ???

 

[mat89RS]

TTT, I really need help, anybody knows ?

 

[Opera House]

It often helps if you provide a more complete description

Like what gears this happens in. You don't need to go to 5K to shift. Try reading some other transmission posts to get an idea what questions to ask. If you don't take the time, we don't take the time.

 

[mat89RS]

I did make every possible searches in this forum and only one person experienced something similar but not the same.



It's doing it in all gears ,2,D,OD

I just can't punch the pedal without having to let it go for the truck to shift, it wont pass 4000rpm.

 

[Opera House]

I have no idea what this means

I just can't punch the pedal without having to let it go for the truck to shift, it wont pass 4000rpm.

 

[mat89RS]

If I put the gas pedal to the floor in WOT (Wide open trottle) the truck (Ford Explorer XLT 94) will not shift.

It will go to 4000rpm and it will hit a rev limiter (fuel or spark cutoff), then tranny (transmission) will not shift (action from going to 2 to D for example) until I let go the gas( let go the gas pedal a bit)


can you ear me now ? ?

 

[AlaskanJack]

This is kinda sounding like a torque converter lockup but I would have to defer to the experts. I hear what you are saying and it happened to me in a car I had like 12 yrs ago. I just can't seem to remember what it was. I had the same problem in order to get it to shift I had to let off the gas a little and then it would shift into drive. But it didn't happen in all gears.

 

[mat89RS]

I seriously have no idea what is making that, my tranny was rebuild 1 week ago and it just perfect... except that small detail.

I can't tell if the truck was doing it before because I bought the truck and next day the tranny blew up, didn't get a chance to push it a bit.

 

[AlaskanJack]

Originally posted by mat89RS
I seriously have no idea what is making that, my tranny was rebuild 1 week ago and it just perfect... except that small detail.

I can't tell if the truck was doing it before because I bought the truck and next day the tranny blew up, didn't get a chance to push it a bit.

Well hell man take it back to the tranny shop let them diagnose it!! Unless you put it in yourself?

 

[mat89RS]

They said the tranny is perfect and it's a problem with the ecm or with a sensor. they have never seen anything like it before. they changed the tranny twice, torque converter once.

 

[Opera House]

Details, details, details

Like it was just rebuilt!

Would this statement be correct?
Engine over speeds in OD, D, manual1 and 2. OK in reverse. Vehicle drives somewhat normally if it is not in a condition of hard acceleration. Fluid is becoming dark and smells burnt.

In general, the following applies
This condition can be caused by a slipping FORWARD CLUTCH. The forward clutch is engaged and stays engaged any time the transmission is in any forward gear. This can be caused by a worn/damaged forward clutch, or low pump pressure as a result of ball check valve sticking, leaking piston seal, or leaking shaft seal that lowers clutch pressure. The forward clutch consists of six alternating metal and friction plates. Under high torque conditions these may slip. In a rebuild this may be because one of the seals was nicked or installed backwards.

With the transmission in reverse or any forward gear and the foot firmly on the brake, the maximum stall speed should be about 3200 rpm. This test should only be performed for a few seconds due to overheating of the transmission. In reverse, this test should be performed with caution on older A4LD transmissions. The known O ring leaking problem may cause the reverse band to slip

In some cases, this may also be caused by damaged overdrive or rear one way clutches.

 

[mat89RS]

Tranny is a rebuilt, I was at the shop when they received it from the company that sold it to them. (since mine was grenaded, traded as a core)

The problem you're describing is not exactly the same. My fluid is red, no burnt smell. the motor does not really over-rev since it wont pass 4000rpm.

With the transmission in reverse or any forward gear and the foot firmly on the brake, the maximum stall speed should be about 3200 rpm. This test should only be performed for a few seconds due to overheating of the transmission. In reverse, this test should be performed with caution on older A4LD transmissions. The known O ring leaking problem may cause the reverse band to slip

My understanding of this test is that if I hold the brake in D and try to spin the tires, it should at a maximum of 3200rpm start to spin the tires ?? is that correct ?, if it doesn't spin, my tranny is slipping ?

 

[Opera House]

The torque converter not only trasnsfers power

but can multiply the torque. At idle the loose fluid coupling places a minimal load on the engine. As the difference between the input and output speed of the TC increases the lead becomes exponentilly larger. At near the stall speed, the engine is so heavily loaded it won't spin any faster. At normal highway speeds there is a lockup clutch that engages in the TC. This eliminates the normal 300-400 rpm loss to make the transmission more efficient.

With your foot on the brake, these internal clutches can be somewhat tested:

Forward clutch - all forward gears
Manual 1 - Low/reverse band
Manual 2 - Intermediate band
Reverse - High reverse clutch and low/reverse band

Gearing is by means planetary gears which reverse the output direction. There are two one way clutches that grab onto the shaft:

Overdrive One Way - All gears except fourth (overdrive)
Rear One Way - Any first gear (manual 1 D or OD first)

By process of elimination you can sometimes determine the problem. If the forward clutch is slipping, the fluid will eventually burn.

I am not convinced by what has been said so far that this is a transmission problem. That you can't get over 4K would seem more like an engine problem.

 

[SteveVB]

Opera may be on to something if the engine wont gain RPMs whether the trans shifts or not the engine rpm should climb. Could be vacuum related. Check out the engine- since you dont know the history it woyuld be a good idea anyway.

If it shifts when you let off the gas I would check the vacuum sources, the hoses to the modulator and the modulator itself. Did they check the modulator valve- it could be the wrong one or if its adjustable be set to shift too high.

 

[mat89RS]

Well the tranny is defenitly slipping today, at WOT the engine spins like it would not be attach to the tranny, also, I cannot go up a hill in 4x4 and 2 gear, again engine just revs, nothing moving !

Also, since it's slipping now, the rpm will go higher then 4000rpm.

The tranny shop owner is comming with me for a test drive thuesday morning.