98 jimmy hard shift

[thebigjimmy]

just got a 98 jimmy today . it has the 4.3 auto trans and 4x4 .
i noticed when shifting from 1st to 2nd and 2nd to 3rd it shifts pretty hard , you even lunge forward a little . just wondering if any1 has had this problem before or has ant input . thanks !

[thebigjimmy]

it also seems to happen only when warm .
the jimmy has 110k on it and i do not know the history ..

[fuzzbutt]

How is the neutral to first shift?

Have you checked your fluid level when the transmission is warm?

This shifting, is it under full throttle or part throttle "taking things easy" type of driving?

Personally a good quick firm shift is what you are looking for. My '98 shifts pretty good at 102900 miles. Things have not changed in the shifting department since I got it at 62k miles. It is a full frame truck though. Your going to feel a lot more things you might not have in a comfy car. Just out of curiosity what is the condition of your shocks? If they are the originals you might have control issues that are amplifying the shift effect.

[MT-2500]

Originally Posted by the big jimmy

just got a 98 jimmy today . it has the 4.3 auto trans and 4x4 .
i noticed when shifting from 1st to 2nd and 2nd to 3rd it shifts pretty hard , you even lunge forward a little . just wondering if any1 has had this problem before or has ant input . thanks !

You need to get it on a full transmission and engine capable scanner to see what is going on.
Check for and post back codes.
In the transmission data stream check shift adaptive data and shift seconds error seconds and shift seconds.
Also the engine has to be running good for transmission to shift good.
And as said check the fluid level and condition.
If transmission has never been serviced drop pan and check filter and see what is in bottom of pan.

[thebigjimmy]

Originally Posted by fuzzbutt

How is the neutral to first shift?

Have you checked your fluid level when the transmission is warm?

This shifting, is it under full throttle or part throttle "taking things easy" type of driving?

Personally a good quick firm shift is what you are looking for. My '98 shifts pretty good at 102900 miles. Things have not changed in the shifting department since I got it at 62k miles. It is a full frame truck though. Your going to feel a lot more things you might not have in a comfy car. Just out of curiosity what is the condition of your shocks? If they are the originals you might have control issues that are amplifying the shift effect.

you cannot even feel the neutral to first shift .

trans fluid level is good and fluid looks new .

it happens during normal acceleration .

the motor tuns very well and the shocks seem fine .

the main thing that concerns me is the fact that it does not do this while the trans is cold , only when at normal operating temp . park to drive is fine and 3rd to 4th is fine also .

today is only my second day day owning this truck or 1 like it so i will be digging into this some more before the snow hits ..

[thebigjimmy]

Originally Posted by thebigjimmy

you cannot even feel the neutral to first shift .

trans fluid level is good and fluid looks new .

it happens during normal acceleration .

the motor tuns very well and the shocks seem fine .

the main thing that concerns me is the fact that it does not do this while the trans is cold , only when at normal operating temp . park to drive is fine and 3rd to 4th is fine also .

today is only my second day day owning this truck or 1 like it so i will be digging into this some more before the snow hits ..

ok , just had it hooked up to a scanner at the parts store today and it is throwing code p1870 .
"P1870 = Transmission Component Slipping = A = *DTC P1870 will be stored in PCM history *Inhibit TCC engagement *Inhibit 4th gear if in hot mode *Freeze 1-2 shift adapts from being updated *Maximum line pressure"

what does this mean ? today it seemed to shift just fine .......
is there anyway to clear this code so i can see if it comes back ?

[MT-2500]

Code is transnmission slippage.
\Not good to drive like that.
Yes clear code with a scanner and see what returns.

It needs to be tested out on a transmission capable scanner not a parts store scanner.
May lead to transmission needs rebiilt or replaced.
But proper testing.
How is fluid and filter and anything in bottom of pan?

[thebigjimmy]

i found a receipt in the truck that says the trans fluid was changed a little more than a yr ago . i pulled the pan it all looked good .

but i just drove it some more and noticed i seem to be having the same problem i have found every were on the web . after driving over 50mph the trans will then shift hard and i get this code . i think i may replace the tcc solenoid and valve body because i can confidently do this myself for $100 and see what happens .

[djd99]

Originally Posted by thebigjimmy

just got a 98 jimmy today . it has the 4.3 auto trans and 4x4 .
i noticed when shifting from 1st to 2nd and 2nd to 3rd it shifts pretty hard , you even lunge forward a little . just wondering if any1 has had this problem before or has ant input . thanks !

I had this same problem with my 98, It was a real hard shift after 20 or so minutes. Turned out to be the transmission valve body. $350 for the part alone and I don't know about labor as I replaced it myself. It took about 4 hours being this was the first time I ever did one. Shifts fine now. Problem gone.

[djd99]

Originally Posted by djd99

I had this same problem with my 98, It was a real hard shift after 20 or so minutes. Turned out to be the transmission valve body. $350 for the part alone and I don't know about labor as I replaced it myself. It took about 4 hours being this was the first time I ever did one. Shifts fine now. Problem gone.

Also in 2000 GM revised the valve body's because they were aware of this problem. no recall

[MT-2500]

Valve body is only a band aid on the real problem.
And very seldom TCC solenoid problem.
The real problem is internal pressure leakage.
The transmission needs replaced or rebuilt for a permanent fix.
It also needs to be put on a transmission capable scanner to see where the slippage is located.