99 S70 AWD Shifting Issue 4th Gear

SAR · Post by **SAR** » 15 Apr 2014, 20:02

Greetings,

I have a 99 S70 AWD with 198K that has some strange behavior on the highway. It seems that the rpm vs. mph flucuates by 200-300 rpm. Sometimes at 65 mph the tach reads about 2200-2300 rpm (normal). Other times it reads 2500-2600 or more.

After ECU reset, things are better but get worse over time. I should also mention that the previous owner installed a tune...he did not have info of exactly what it was or who it was from. He installed a 16t and the tune was supposedly related to that.

What I've done:
1. MAF
2. xeMODex ETM (had a code)
3. Trans drain and fill (times 4)

I would appreciate any suggestions on what I can look at next. I commute about 100 mi. a day and would like to get to the end of this strange story.

Thanks in advance.

Post by **rmmagow** » 16 Apr 2014, 07:45

Do you think it might be your lock-up torque converter or solenoid? That variation would roughly be what you'd see when the TC disengages upon acceleration. Try setting the the transmission to E and see if anything changes.

SAR · Post by **SAR** » 16 Apr 2014, 09:21

What do you mean by setting the transmission to E?

Bluevanacd2005 · Post by **Bluevanacd2005** » 16 Apr 2014, 17:32

The trans should have a sport or economy mode you can put it in. Never had a S70 so I don't know the exact location of the switch but on my 850 it was right by the shifter.

Spenser

SAR · Post by **SAR** » 16 Apr 2014, 17:40

The awd 4 speed doesn’t have econ mode.

Post by **burnout8488** » 16 Apr 2014, 19:05

All 99+ lack the S E W buttons.