TC lockup
TC lockup Odd question, but how EXACTLY can you tell if the TC is locking up at cruise speed?
I was driving home today, when I noticed my "instant mpg" was lower than usual at 60mph (16-18 instead of the 23-25 normal) The rpm seemed to be a little higher (2000 instead of 1800-1900 from memory) and my trans temps were climbing to the 220 range normally in the 195-200 range although it WAS hot)
I rechecked my lock up values and they seemed correct, but just wondered if there was somthing else to check.
I was driving home today, when I noticed my "instant mpg" was lower than usual at 60mph (16-18 instead of the 23-25 normal) The rpm seemed to be a little higher (2000 instead of 1800-1900 from memory) and my trans temps were climbing to the 220 range normally in the 195-200 range although it WAS hot)
I rechecked my lock up values and they seemed correct, but just wondered if there was somthing else to check.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
When the TCC locks then it feels like a manual transmission in high gear, and the rpm stays steady, even when the throttle is moved within the range of the apply/release tables without exceeding the curves.
The easiest way to check is to drive it. Just get to normal driving speed with steady throttle, at about 55-60 mph touch the brake pedal and watch the tach, if the rpm climbs a few hundred then the converter is unlocking. You should also be able to feel it.
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If your cruising and give it more throttle and the rpms stay put but you mph is increasing then its locked up. If you give it more throttle and the rpms jump up then its unlocked at that point.
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Thanks for the responses
The three main reasons I was concerned about the lock up was the differeces in;
1. My trans temps, which NEVER go above 215 unless I'm maybe in the mountains
(received my new trans cooler today to address that
)
2. My "instant mpg" on a flat road is usually around 24-25, but it was in the teens. I was definitly in OD
2. My rpm is usually around 1800 at 60 mph, but was dead on 2000. I verified this by driving my wifes car with has the same rear (3.42) and a stall, and it was running 1800.
The trans is a new (less than 1000 miles) RPM stage V, so the fluid is new.
I changed the pressure settings on the TCC and will download and test again this weekend.
I'll try some of the "test" posted.
Thanks again
The three main reasons I was concerned about the lock up was the differeces in;
1. My trans temps, which NEVER go above 215 unless I'm maybe in the mountains
(received my new trans cooler today to address that)2. My "instant mpg" on a flat road is usually around 24-25, but it was in the teens. I was definitly in OD
2. My rpm is usually around 1800 at 60 mph, but was dead on 2000. I verified this by driving my wifes car with has the same rear (3.42) and a stall, and it was running 1800.
The trans is a new (less than 1000 miles) RPM stage V, so the fluid is new.
I changed the pressure settings on the TCC and will download and test again this weekend.
I'll try some of the "test" posted.
Thanks again