Symptoms and signs of transmission troubles

[dmg4]

My 2008 V70 has 137,000 miles on the clock. Over the last 2 months, it has developed what might be a transmission problem.

1. Uphill, on our driveway, at 5 mph, very little throttle applied, the car seems to be momentarily slipping or staggering. It's probably in 2nd gear. The slip is very brief, and the engine seems to lose power. RPMs do not increase.
2. At higher speeds, and when you apply more throttle, in gear 3 and up, there is plenty of power. Gas mileage is normal. No breakdown under WOT and RPMs easily reach 6500 before upshifting under max acceleration. No lack of power and engine seems to run great.

I had the transmission fluid changed, which was dark. Less than 10,000 miles later, it was dark again. Drained it again, and completely flushed the system. Symptoms persisted. Local shop replaced all the coils and fuel pressure regulator. The foregoing repair might have been needed, but did absolutely nothing to relieve the symptoms.

Ideas on most likely cause? Go back to the same shop, or try elsewhere; perhaps a transmission shop?

[dmg4]

OK, there's more: I drove it around every hill and parking lot in town this morning, letting the auto-trans shift, and then manually shifting through the lower gears. The feeling that the car is hesitating or staggering on gentle inclines is definitely happening in 2nd gear, and there is a momentary shuddering as it shifts from 2nd to 3rd.

So, what are the reasonable suspects here? Is there an electronics control module associated with shifting that's on the fritz? A stuffed-up valve? Metastatic tranny cancer?

[dmg4]

Hey! Where are all the forum experts?

OK, the problem has been resolved. It was a combination of dirty transmission fluid and and ignition problem at low RPM under load. The dirty trans fluid was a red herring with respect to the hesitation... totally unrelated. It was just dirty, and it took a few changes to clear it, as you never get ALL the dirty fluid out in one change. The hesitation was bad grounds on the block and cylinder head. Not enough to trip a CEL, but enough to store codes for random misfires. Cleaned all grounds, and coated with dielectric grease, as well as cleaned and similarly coated the connections to all coils, and the hesitation was gone.

I'll run the car for another few hundred miles and change out the transmission fluid one more time.

Now I need to disappoint all of those car sales people I contacted, anticipating that I likely needed to replace the car.

[pgill]

Hey! Where are all the forum experts?

...............The hesitation was bad grounds on the block and cylinder head. Not enough to trip a CEL, but enough to store codes for random misfires. Cleaned all grounds, and coated with dielectric grease, as well as cleaned and similarly coated the connections to all coils, and the hesitation was gone..............

Now I need to disappoint all of those car sales people I contacted, anticipating that I likely needed to replace the car.

Excellent diagnostic work.

I will need to add this to the common faults.

Can you clarify which connections you cleaned?

Did you measure the Voltage Drop at those connections with the Engine running? (Exposed metal on the crimp shown in the picture below to the Battery (-) post)?

Some pictures that may help

GND_1.jpg (181.03 KiB) Viewed 1388 times

GND_2.jpg (169.08 KiB) Viewed 1388 times

Note: the wiring diagram is for a LR2 that uses the same engine as your V70

COIL_1.jpg (40.57 KiB) Viewed 1388 times

COIL_2.jpg (44.31 KiB) Viewed 1388 times

Did you find this connection for the ground? Note: yours won't say Land Rover but it will be connected in the same location.






If you want to know more about what to look after on your 3.2 you can use this link

https://www.freel2.com/forum/topic32504.html

or check to see what I did for my S80 3.2

viewtopic.php?f=31&t=87687


Good luck

Paul

2008 LR2 3.2
2010 S80 3.2