Auto transmission drops to 2nd gear on the smallest hill

[bruggz351]

I'm interested too.
The white XJ tends to shift a little too early in my opinion. The blue XJ held OD much longer. I've been too busy with other jobs to concentrate on this. But I'll soon be able, as I'm installing the RADesigns Rail controller.

[werd]

Originally Posted by alexbrown64

Do you definitely know your diff ratios?

Good luck,
Cheers,

No I don't. I was told how to check but I don't remember. I will see if I can find the info again. It involved taking off the back diff cover, jacking up a rear tyre, rotating it and count the diff revolutions or something.

Found this diff guide, but I still need to eyeball it.


I'm not fixing it, I'm improving it!!!

[alexbrown64]

You dont have to drain your fluid and remove your cover. I found this on the net and its easy and accurate..

The easiest way is to chock the other wheel if you don't have an LSD, if you do have an LSD you don't need to. Mark the wheel and shaft in the same way, then turn the WHEEL not the shaft. Turn the wheel 10 times and count the shaft revolutions. For a 3.73 diff, with a none LSD the shaft will turn just over 18.5 times (18.65). Multiply by 2 which gives you 37.3. You have turned the wheel 10 times so you need to divide by 10 giving you 3.73. If it's an LSD axle then it will turn 37.3 times, so go straight to dividing by 10

Cheers,

[werd]

More diagnostic info:
When traveling at 70 or 80 kph, if I manually shift from drive to 3rd, the car goes to second and then to third.

I'm wondering if the torque converter is not locking up?

I'm not fixing it, I'm improving it!!!

[rustynuts]

Originally Posted by werd

More diagnostic info:
When traveling at 70 or 80 kph, if I manually shift from drive to 3rd, the car goes to second and then to third.

I'm wondering if the torque converter is not locking up?

I'm not fixing it, I'm improving it!!!

It's easy to know when your torque convertor is not locking up. When locked up you can feel it. Your car will drive with a solid hookup between the engine and the wheels. A slight push on the accelerator under light load shouldn't move the tach much.
When not locked up, a slight push on the gas pedal will will rev the engine up more before an increase in speed.
TC lockup can feel like the next higher gear. When it unlocks , that can sometimes feel like a downshift.

[werd]

Originally Posted by werd

I'm shooting on the dark here, but the VSS (Vehicle Speed Sensor) may be faulty.

I've also noticed a difference in distance traveled between the dashboard odometer and the overhead console. It's only about 0.4% (1000km/1004km)
I'm not sure how the two systems get their data. Perhaps the discrepancy supports that the VSS is faulty.

I'm not fixing it, I'm improving it!!!

[werd]

Well, I swapped out the speed sensor. There is no change.
Driving around today, just for kicks I thought I would drive "manually". Dropped it down to first/second. Stayed in first the whole time. The only time it went to second was when I shifted to third.

I'm not fixing it, I'm improving it!!!