Tranny slip on 1-2 shift (1 Viewer)

[100monster]

I'm helping a buddy of mine work on his 99LC 100 and the tranny shifts nice when accelerating slowly. The problem is if you accelerate quickly, as if you just pulled out in traffic, there is a huge delay(2 sec or so) between 1st and 2nd gear and then WHAM! It shifts into gear very firmly. The fluid is pretty new and topped off. Does this have bands that need adjusting or are the clutch packs worn out? Anyone try Lucas or any other Snake Oil to solve something like this?

 

[Travis351]

Is this a new symptom? Mine has been doing that since I bought it. Hold off on the additives.

 

[2000UZJ]

Mine shifts slowly at full throttle. It slowly setups up for 2nd (probably a good full second) then bangs into 2nd gear. Mine has done it since we bought it 10 years and 130K miles ago.

 

[NMuzj100]

Maybe some of the feed back is a result of the entire drive train reacting rather than just the transmission. There is a lot of running gear to bring into motion. Might try lubing the drive shafts. Also search "thunk" and see if that is what your are dealing with.

Try flooring it in Low range and it'll snap your neck around.

additives - just say NO!

 

[wareagle]

You might want to disconnect the battery for about 10 minutes, then touch brake pedal. This will ensure that ECU is reset. The reset will often help with tranny and drive by wire "delays".

I have to do this on the 100 series and gs430 whenever my wife drives too long. Our driving styles are quite different, so this is the best way to reset the "fuzzy logic".

 

[100monster]

This truck has been doing the same thing since my friend bought it a year ago. I guess i will try the battery trick to reset the PFM (Pure F****** magic) box. I also read a great thread in the FJ80 section where you can drop the pan and adjust a valve with a screwdriver to firm up the shifts. I know these trucks shared the same A343 trannies as the late model FJ80. I'm hoping it has the same thing. Anyone know?

 

[davegonz]

This truck has been doing the same thing since my friend bought it a year ago. I guess i will try the battery trick to reset the PFM (Pure F****** magic) box. I also read a great thread in the FJ80 section where you can drop the pan and adjust a valve with a screwdriver to firm up the shifts. I know these trucks shared the same A343 trannies as the late model FJ80. I'm hoping it has the same thing. Anyone know?

Can you post a link to that 80-section tech? Might come in handy.

 

[96r50]

https://forum.ih8mud.com/80-series-tech/349909-improving-transmission-shifting.html

 

[100monster]

That's the one! Anyone tried this on the 100? Is it the same?

 

[100monster]

I tried the ECU reset, shifts a little different but still have the same problem.

 

[100monster]

So has any tried dropping the pan and turning the shift firmness valve, if it has one?

 

[bamachem]

https://forum.ih8mud.com/80-series-tech/349909-improving-transmission-shifting.html

I am going to have to try this on Saturday...

 

[OregonLC]

I am going to have to try this on Saturday...

I just quickly skimmed through the link. Does it apply to the 100's also?

 

[bamachem]

Late 80's (96/97) share the same auto trans as the 4-speed Hundys.

 

[Tools R Us]

That's the one! Anyone tried this on the 100? Is it the same?

Late 80's (96/97) share the same auto trans as the 4-speed Hundys.

Maybe, maybe not. The 34XX trans has been used in lots of vehicles, over a long time, over that time there have been changes. On some of the later units the system pressure is controlled by the ECU. Most of the newer "electronic driver aid" rigs have ECU control. One indicator is the cable from the throttle body to trans (the so called kick-down cable), if it is on the rig, it has the progressive regulator, so is mechanical control. If the cable isn't used, it is electronic control, to adjust/change shifting, would need to reprogram/cheat the ECU.