The concept of torque converter (ToC) lockup was once referred to by Gerrit Loubser when we discussed towing and gear ratios. I did a lot of thinking since then and came to the conclusion that the gear ratio chosen during towing should be such that the ToC stay in lock-up as much as possible. I then tried to establish at what revs this happens by tapping on and off with the right foot at various engine speeds but I seem to get rev-gain and rev reduction whenever tapping on and off throughout the rev range. Is this a good way of determining the lockup point and if not where is the lock-up point? Do we really have a lock-up ToC on the 3.2 DID? Lockup ToC's became popular around the 1980’s but did all manufacturers go that route?
I would really appreciate comments from all you clever guys out there. Thanks.
Affiliate Member
The lockup is variable and gets determined by the autobox computer. Although I believe it only locks in 4th and 5th
I suspect you may be able to wire in a status light for the lockup converter if you wanted to.
The difference between lock and slip is usually about 300 rpm. If it locked and you give moderate gas you will notice that the rise in rpm is similar to the speed like a manual box. If it isn't locked and you give moderate gas you will notice a quick spike in the revs
I suspect you may be able to wire in a status light for the lockup converter if you wanted to.
The difference between lock and slip is usually about 300 rpm. If it locked and you give moderate gas you will notice that the rise in rpm is similar to the speed like a manual box. If it isn't locked and you give moderate gas you will notice a quick spike in the revs
The torque converter is locked by means of a small lock-up clutch. This clutch has limited torque trnansfer capacity, so lock-up is only allowed by the transmission ECU in the high gears and under throttle openings that would not lead to torque in excess of the lock-up clutch's abilities. This means that lock-up is not a simple function of speed.
Gerrit Loubser 
2003 Toyota Land Cruiser 100 VX TD
2003 Mitsubishi Pajero 3.2 DiD LWB A/T Gone & missed
1999 Nissan Patrol 4.5E GRX M/T: Gone & missed
1996 Toyota Land Cruiser 80 VX 4.5 EFI A/T: SOLD
2003 Toyota Land Cruiser 100 VX TD
2003 Mitsubishi Pajero 3.2 DiD LWB A/T Gone & missed
1999 Nissan Patrol 4.5E GRX M/T: Gone & missed
1996 Toyota Land Cruiser 80 VX 4.5 EFI A/T: SOLD
Thanks guys. So it is electronics again which reacts according to some engineer's way of thinking. Interersting then is that it seems to only play a role during "plain sailing". Any exception in load or throttle could cause the lock to drop out. I can understand why it is done like that. Else how would smooth shifting between the ratios be possible. Now, for the towing community the question remains: Does it actually lock in 4th as well. Again I recall that in the earlier models of cars it only worked with 5th gear. Toyota and others advertised a lock-up 5th.
Willie from Jo'burg
White Gen 3 SWB Pajero 3.2 DID
White Gen 3 SWB Pajero 3.2 DID
Bigwill,
Yes, it will lock in 4th as well.
If you continue with your experimenting under load (like most of have done I guess), you will find a sweet-spot in 4th where it will lock-up, but not in 5th. The interesting part is that the fuel consumption (with my 3.8V6) is almost 20% higher in 4th than in 5th under those heavy towing conditions (20l/100km vs 18l/100km). I eventually decided to stay in auto mode and leave the decision making to the ECU. The only time I would interfere by using the tiptronic is to avoid unnecessary up and down shifting by the ECU in undulating country. Then I'll choose 4th and maybe drop my speed to 100 from 110.
I am convinced that these gearboxes are very robust and that the ECU can be trusted. The ECU doesn't have a "look forward" device, so it cannot anticipate what lies ahead, which is why I take over under undulating conditions.
Roelf
Yes, it will lock in 4th as well.
If you continue with your experimenting under load (like most of have done I guess), you will find a sweet-spot in 4th where it will lock-up, but not in 5th. The interesting part is that the fuel consumption (with my 3.8V6) is almost 20% higher in 4th than in 5th under those heavy towing conditions (20l/100km vs 18l/100km). I eventually decided to stay in auto mode and leave the decision making to the ECU. The only time I would interfere by using the tiptronic is to avoid unnecessary up and down shifting by the ECU in undulating country. Then I'll choose 4th and maybe drop my speed to 100 from 110.
I am convinced that these gearboxes are very robust and that the ECU can be trusted. The ECU doesn't have a "look forward" device, so it cannot anticipate what lies ahead, which is why I take over under undulating conditions.
Roelf