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auto/4.88's trouble with shift points: RPMS too low

blondejoncherokee

blondejoncherokee

NAXJA Member
NAXJA Member
Location
sacramento
alright ive noticed a couple things with my tranny lately.

good:
my tranny wont shift out of 1st while in 1-2. i like that.

bad:
shifts a little back and forth between 2nd and 3rd gear up in the mountains.
it will go up to 2200rpms max in second gear before it shifts into 3rd, way too early, and it sucks full of gear up heading out to the trails.
good power in first.
good power in 3 when it hits 2400-3000rpms, but i have to get it up to like 45-65mph to get there.
4.88s and an aw4 and 33's
could this be a bad tps?
it still shifts into OD in od.
i just wished it would stay in 2nd until about 2600-3000 rpms,
other than that im happy.

could it be bad solenoid in the tranny?
bad tps?
exhuast leak?
i dunno...
 
Have you changed the speedo drive gear to compensate for the gear/tire combo? If not I would bet that is the problem. The TCU uses the ground speed information to set the shift points.
 
i didnt know the speedo gear had anything to do with that?
so the tcu uses it huh?
i assumed it was mechanical and just for the speed...
 
im also having this same problem with an 89 i just picked up with 3.55's and 33's. it just shifts to soon it seems like? how do you cure this and is there a chart or something for reference to gears and tire combos? and where would i buy this speedo gear? (sorry not trying to steal your thread! some more info would be nice though =)
 
i love my 4.88s with the 33's though.
i just picked up a new tps
also grabbed exhaust manifold gasket, flange gasket, cat gasket, intake gasket
need bolts and threaded rod to finish it all and ill be ready to try to work out any exhaust leak gremlins...
i also have a new egr lying around somewhere...
 
can anyone verify that the speedo gear will cause this problem?
it doesnt seem that would cause a problem....
 
alright,
60$ autozone TPS fixed it!
so much power back, and put the shift points back up to normal
it now shifts from 2-3 at 2800-3200 rpms instead of 2200 rpms,
very very noticable throttle response.
some small things i also did that could have had an effect:
sprayed out throttle body
cleaned K&N cone air filter
but these 2 things are something i do after every long wheeling/camping trip with little change...

i also cleaned all fuel injector electrical connections
this possibly could have been it

but im attributing it to the stock tps wearing out in some spots and sending bad signals back to the tcu and ecu as the main problem
 
it also starts up faster and idles better as well now
 
well i still need to do the speedo gear cuz i want my speedo to read correctly. i just want to find one cheap
 
Nice job on the 60 buck TPS. Round here can't get em for under 80, and woe be to you if you have a manual trans they'll jack you for a c note. This is at the local Auto Zone.
 
i noticed the ones for the manual are 98$...
and i had 20$ on the autozne rewards card so it was even cheaper
 
Is there any difference between a $80 TPS and a $120 TPS? They all have a 1 year warranty, seems like you are paying for the name?




I am having this exact same issue with my 89. Shifts at around 1500 rpms when I get on it, and is always in to high a gear. Im in 4th at about 30mph, 3rd at around 20. Its dumb.
 
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