Automatic transmissons
 

Can someone please educate me on automatic transmissions aging and remedies?
My first A/T car is a Nissan X-terra, that has now 124,000 miles on it. The engine is still strong, but the transmission has become sluggish: the clutch slips too much, and shifting (up and down) is slower than it used to be. I replaced transmission oil already, and did not feel a difference. Is that how A/T cars die? Is there a remedy, adjustments to do or parts to replace?

Aurel

Where to start....the auto trans is filled with muliple clutches, hydraulic circuits, a pump(s), piston rings and other mechanical parts; any of which can wear or fail, then add the break-down of the fluid and possibility of sludge.

The clutch packs are self adjusting and wear or failure is usually a result of a hydraulic problem ( worn converter or oil pump, old fluid or sludge in passages). Bands need periodic manual adjustment which is usually done from the external part of the case or thru the pan. Worn converters, pumps, rings can cause a loss of overall hydraulic pressure and can only be remedied by replacement; at which time a full rebuid is in order. The valve body can be affected by both wear and sludge/varnish, it's the "brain" of the hydraulic circuit, and where most trans problems originate.

Not familiar with this particular model; it may have external controls driven by cables or vacuum that can be adjusted or replaced, and the actual linkage to the shifter can be out of adjustment, which can cause improper fluid routing.

Overall poor performance is (generally) indicative of age and wear; where specific single-gear probs are usually adjustment faults.

Unless you are going to tackle it yourself (with proper tools and manuals), the first hurdle is to find a truly reputable auto trans shop (needle/haystack), and have it serviced fully.

Although 124K miles isn't high by todays standards, it's high enough to weigh the rebuild or replace option based on cost vs. just servicing it.

Newer auto trans get a signal from the computer. Is your check engine light on? If so have the codes read. I dont know about Nissan but other maker are affected by fuses, broken/burnt wires and fried solenoids. Some which will put you in limp home mode. I am sure X-terra has a fan website. Check it out.

Thanks for the advice. Yes my check engine light is on when I start. I`ll have those codes read.

Aurel

Your Check Engine Light should ALWAYS come on when you start the engine. Only need to check if it doesn't go out after several seconds.

Doh, Ok. No it does not stay on. Always wondered about that.

Aurel

you should check out xterraownersclub.com

Im a member of there and it contains the answer to just about every question ever asked about Xterras