98 v70 lntermittent lack of power/downshifting [ATF level] Topic is solved

yanga001 · Post by **yanga001** » 22 Jan 2020, 23:27

Hi everyone,

So recently our new v70 has had issues with acceleration at a variety of speeds. It will operate normally when not heavily loaded, however when the throttle is depressed fully the car does not seem to downshift. Instead, it just elevates the rpms to rediculous levels and acts like a pig. It seems that letting off the throttle and then depressing it again will allow the car to downshift and overcome the issue. I just did the first drain and fill on the tranny and saw no excessive buildup or flakes in the fluid.

The car was fitted with a dual series muffler system so it could be offering a lot of resistance to the exhaust, however i do not see how it could result in a lack of shifting. The transmission feels smoother then our previous 98 v70, and there are no noticeable issues with the car slipping out or hesitating between normal operation. It seems that just the full depress or kickdown activation us where the car will have issues. I did pull a p0172 and 0422 from the obd port, which showed up after we tried pushing the throttle fully for the first few times. Aside from that the car has no check engine codes as verified by our indie mechanic and personal scanners.

What kind of things should we look for, could the cable be out of adjustment and then not activate the downshift?

Thanks in advance.

Post by **RickHaleParker** » 23 Jan 2020, 00:45

The 1998s have a Kickdown switch on the Throttle cable and in mounted in the firewall. Sometimes the switch mount splits and separates from the firewall. If this is your case replace the Throttle cable/ Kickdown switch and adjust the cable.

If this is not the case, check the Electrical Connector, Wiring, Switch functionality and Throttle Cable adjustment.

yanga001 · Post by **yanga001** » 23 Jan 2020, 23:24

So i checked the cable and it looks brand new, no indications of it being loose. I did the glove test for the PCV system and it failed. Oddly enough i pulled the dipstick to relieve pressure and took a few rips in the car to see if i could recreate the aformentioned behavior. Surprisingly i could not repeat it on either sport or economy modes. Could a clogged PCV system cause the car to act sluggish and not shift?

Post by **RickHaleParker** » 23 Jan 2020, 23:35

RickHaleParker wrote: ↑23 Jan 2020, 00:45 If this is not the case, check the Electrical Connector, Wiring, Switch functionality and Throttle Cable adjustment.

yanga001 · Post by **yanga001** » 24 Jan 2020, 05:27

RickHaleParker wrote: ↑23 Jan 2020, 23:35
RickHaleParker wrote: ↑23 Jan 2020, 00:45 If this is not the case, check the Electrical Connector, Wiring, Switch functionality and Throttle Cable adjustment.

i should have been clearer earlier, i checked those items and found no issues. That is why i was did a full check on the car and found issues with the PCV.

yanga001 · Post by **yanga001** » 24 Jan 2020, 22:06

So it seems that it may have been an issue with the transmission fluid levels. Upon topping it up the car returned to normal operation. PCV was unrelated and likely a foolish lead to try and follow. Thanks for the help, there was slack in the cable so i did adjust it. The car ran great after topping it up and i will continue to test it to verify a solution.

Post by **RickHaleParker** » 24 Jan 2020, 23:45

yanga001 wrote: ↑24 Jan 2020, 22:06 PCV was unrelated and likely a foolish lead to try and follow.

If the PCV failed the glove test you found an issue that needs to be dealt with.

A failed PCV can cause sludge build-up, which is one of the few things that can kill the almost bulletproof Volvo lower end.

If the Kickdown switch closes before the throttle position reaches 85% DTC code AT-143 will be set.

yanga001 · Post by **yanga001** » 25 Jan 2020, 06:57

I am dealing with it, but i meant it would be unrelated to the kickdown issue. Ill take a look at the DTCs again to see if any new ones came up

Post by **abscate** » 25 Jan 2020, 07:04

yanga001 wrote: ↑24 Jan 2020, 22:06 So it seems that it may have been an issue with the transmission fluid levels. Upon topping it up the car returned to normal operation. PCV was unrelated and likely a foolish lead to try and follow. Thanks for the help, there was slack in the cable so i did adjust it. The car ran great after topping it up and i will continue to test it to verify a solution.

Ah, I missed this “obvious “ remedy.

Poor shifting , first check should be fluid level and type

For reference , transmission oil is checked following manual
Procedure, completely different from engine oil check.

yanga001 · Post by **yanga001** » 25 Jan 2020, 11:02

I had done a drain and fill and it seemed to temporarily fix it for a bit and i misattributed that to another cause earlier. It seems that the previous owner had it drained at a shop (not a powerflush according to the receipt) and they did not put in enough fluid. I did the normal drain and fill for 4 qts and the car would not shift down when going about 70 km/h. After an interesting highway exit and topping it up things seemed to return to normal. Drove it another 30 km today and shifted it through the gears and everything seems fine now. Time to tackle the pcv and a loose exhaust manifold. Thanks for the help!