92 trooper AT harsh up-shifting 2nd to 3rd only


Dang it! à i just knew if i started lurking around here again, and even chiming in on a post or two, something would pop up (or off). <img src="/forums/images/graemlins/lol.gif" alt="" />
And so it has. . . any help greatly appreciated.

This started ôall-of-a-suddenö, after driving 5 miles in hot weather, parking in the shade, and then when driving back within a mile or so. So, hereÆs the info:


PROBLEM:
auto transmission up-shifting harsh from 2nd to 3rd *only*. . .(apparently)

WHEN:
only during regular non-aggressive around-town driving.
***** (if i push it at higher rpmÆs, both in full automatic mode and when manually shifting, with and without power switch on, it does seem perfectly OK.) mmmmmà

other checks
No Check Trans light
Fluid check:
Level: Hot level at Min mark (so not real low)
Color: light brown (not new pink color, æcause it is not new; and not dark brown or burnt color)
Odor: no burnt aroma at all
Not aware of any slipping

My isuzu service manual supplement for this trans isnÆt a whole lot of help because it mainly is concerned with using the Tech-1 diagnostic tool to troubleshoot.

Any ideas? I was thinking low fluid level because of higher rpmÆs seemed to fix the problem, but the level seems ok, though not perfect.

Plus, iÆm surprised itÆs only the upshift from 2 to 3 and not paired with any other up-shift points.

IÆm going to try adding a little trans fluid on the off chance thatÆs it (but i doubt it).

Btw, æsearchÆ hasnÆt helped so far.
Thanks in advance

1992 isuzu trooper, automatic transmission 4L30-E

I had a similar problem with my '93 automatic, tended to shift rough going from 2nd to 3rd and slip a little. It didn't happen all the time but seemed to get slowly worse. Anyway, I had a trans place check it out and turned out I needed to have it rebuilt: cost - 2,500.00. <img src="/forums/images/graemlins/scared.gif" alt="" /> This happened around 98,000 mi. Have it looked at, I think I waited too long

Is it the mode switch?

the harsh shifting is now through all up shifts and all downshifts, but not necessarily all the time.<img src="/forums/images/graemlins/rolleyes.gif" alt="" />

But, driving with the gear shifter at 3, æfixesÆ the problem û all up-shifts and down-shifts seem fine. Also, manual shifting is good. This seems to rule out the 2/3 shift solenoid in the trans, as well as more hair-pulling possibilities like clutches, etc. do you agree?

So thanks JGAGS. iÆm hoping that the rebuild option wonÆt be the case.[cross-fingers graemlin]

with some good search hits for my symptoms at planetisuzoo, and then re-searching here at 4x4forum (i didnÆt have much luck searching here at first),
i'm thinking it could be the AT mode switch, also variously called the range sensor, position selector or any combination thereof.

This sensor/switch sits around the shift shaft at the trans. According to my helms manual it transmits up to 5 different signals in different combinations for the seven gear selector positions û PRND32L.

What happens with my trooper generally fits what these threads report, and their remove-clean-reinstall scenario might be worthwhile.

I think iÆll give it a couple of days to confirm the symptoms etc., check the prices for a new part, and then decide whether to replace or to remove, clean, re-grease, reinstall

Any opinions?
anybody do this recently? did it hold up?
Your feedback is greatly appreciated.
Thanks in advance.



SOME LINKS . . . for now and for back-to-the-future searchers

4L30e Transmission Shifting Problems û with Solution û***** very good post, in the archives of .planetisuzoo

range sensor pdf *****very good pixs. from Amigo-2kÆs compilation extravaganza

transmission clunk .planetisuzoo

Newbie: Transmission or Sensor? .planetisuzoo

99 Trooper AT Mode Switch Saga .4x4wire

Transmission Problem .4x4wire

A/T Tranny Gear Indicator .4x4wire

A/T Tranny Gear Indicator .4x4wire

tranny trouble .vehiCROSSinfo


SOME SEARCH TAGS
mode switch selector sensor range position 4L30-E automatic transmission harsh hard shift 92 trooper isuzu upshift 2nd to 3rd

Well, on to remove and clean the mode switch/range sensor.


iÆve lived with this a bit, and symptoms remain constant:




Cleaning this switch seems worth the try after reading and conferring, especially since some have had success, and the part has a dealer list of $193 American.

Hey -- wish me luck, i think iÆll need it crawling under there with the grit and grime falling in my face in this heat!

Any last words of advice? any and all hand holding greatly appreciated (and needed on this).

bc


P.S. i goofed the links list in the above post and by the time i noticed, my edit time had expired <img src="/forums/images/graemlins/sleeping.gif" alt="" /> . (who knew?) so hereÆs the correct list (getting rid of one duplicate and adding one link that got left off ------

SOME LINKS . . .corrected....

4L30e Transmission Shifting Problems û with Solution û***** very good post, in the archives of .planetisuzoo

range sensor pdf *****very good pixs. from Amigo-2kÆs compilation extravaganza

transmission clunk .planetisuzoo

Newbie: Transmission or Sensor? .planetisuzoo

99 Trooper AT Mode Switch Saga .4x4wire

Transmission Problem...... .4x4wire

A/T Tranny Gear Indicator .4x4wire

auto transmission glitch .automotiveforums

tranny trouble .vehiCROSSinfo