Astralplane

1994 3.0 4Runner A/T
The problem started about 3 weeks ago.
Put it in reverse and it shifted hard enough to chirp the tires and it shifted equally as hard in drive and when it shifts to second.
But once everything is up to normal operating temperature, tranmission operates normal again. I have no fault codes. Fluid as been changed every 30K, but the pan has never been dropped.

This is what I have done so far:
Manually changed the fluid and put in a new t-stat.
Checked the kick-down cable.

My question is why this happens only when its cold?
Would a bad temp sensor cause this?
I've looked through all the transmission info from the factory manual found on-line, but it doesn't address how or if temp sensors affect the transmission.

Also, should I take to the dealer or a transmission shop?

Thanks for any help

FredTJ

Is it shifting "hard" into reverse or drive (when cold) because your idle is waaaayyy high, like 1500 rpm or so ?





Fred

SEAIRESCUE

As suggested, what is the idle speed when you shift, cold? Idle speed may be too high.

If the shift delay cable is not sticking and properly adjusted, and your idle is about 1000 RPM, then you have a problem that needs to be evaluated. First, is the transmission logging any codes? Is the fluid level dead on when hot and at idle? The delay cable raises the internal pressure as it is pulled by the throttle.
Problems with the cable will slam the transmission and cause it to shift at much higher RPM's.

Let us know what you find.

Astralplane

Idle is normal and it not an RPM problem. No codes
Also, after it hard shifts a few times when cold, it will then soft shift or roll from one gear to the next for a few shifts and the shift normal after up to normal temp.
Also, before I changed the t-stat it was taking forever to get into OD.
I've had the truck since it was brand new and the transmission has acted normal until a Monday morning about three weeks ago.

What is a delay cable ?

Thanks Again

881stGenRunner

subscribing, im having similar problems.

loki

I have a similar problem on a 93 I just bought - but may back out of if it's a 'real' problem. Mine has trouble with 1 to 2 and 2 to 3. It was about 40 degrees here. After about 2 miles it was OK. No problems with OD.

Wierd thing... My last vehicle, a 86 Bronco 2 did the same thing. They never found it's problem. Even a new transmission did not fix it. It went away after a rebuild transfer case (that was not the problem, but something done while doing this fixed it)

So what could it be? Mine shifts perfectly when warm.

T-1000

Mine does the exact same thing. Not quite as hard though...

I thinks it's just because I often take off before the engine has warmed up enough to get down to normal idle speed.

I figure as long as it shifts hard, it's OK.

Tubbyfatty

Id just go to aamco if you dont know what to do. They take it for a short test drive then throw it up on a lift and check it all out. Most of the time they do checks for free.

buckz6319

My A340H tranny shifts hard when warmed up to operating temp.It also feels like I have a lot more slack in the tranny when warmed up every thing feels looser than when cold.I have a lot of problems with my A340H but for some reason it's still going and I have tried to fix it to no avail I'm just waiting on it to die so I can install another
I wish I new what your problem is because it may help me diagnosis mine.I don't have any tranny codes either....

Flash319

Just to throw this out there but maybe your torque coverter is not unlocking when you park the truck. Then when you go to go into gear the coverter is locked causing a hard shift.

FredTJ

If the TC was stuck locked, it would be just like a manual tranny that's in gear and no clutch when you come to a stop, that is the engine would stall out assuming your brakes could/would hold the vehicle and completely stop it.




Fred

Flash319

Good point....

InternetRoadkill

I'm wondering if the seals and o-rings are just getting old and causing the accumulators to stick when cold.

ZUK

iTrader: (1)

If it were my own truck.....I'd drop the pan and change the filter....add new oil along with a quart of that "KW" tune-up additive that claims to improve shifting.

1styota4X4

have you sat in the truck and let it warm up for a few min. before you started going...If that dosent help i have a fresh rebuilt 1993 transmission for sale 3.0v6 4x4 is what it came out of...let me know