Auto Trans kick back/change down with cruise control on

[Joep1957 Lurker Find all posts View Profile Close Joep1957]

Hi. Question for anyone with a 90 series Prado with an auto trans. When travelling at highway speeds on undulating road with the cruise control on - does the auto trans have a tendency to kick back/change down harshly into 3rd to try & maintain the set speed? Thanks

[BiLLz0r Advanced Member Find all posts View Profile Close BiLLz0r]

It's normal. The 120's do it too.

[Darran K Member Find all posts View Profile Close Darran K]

Yep mine does it.

[Beach Advanced Member Find all posts View Profile Close Beach]

Same. Bloody annoying too.

[mybo Member Find all posts View Profile Close mybo]

I have a 120, and yep.. I hate it.. I pretty much only use cruise on flat roads because of this.

[Ian Reid Advanced Member Find all posts View Profile Close Ian Reid]

Yep my 90 does it, screams up the hill then hangs for ages before going into OD


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[scottkz Senior Member Find all posts View Profile Close scottkz]

yep its normal CRAP system
Diesel is a different story though 1000% better than V6

[Joep1957 Lurker Find all posts View Profile Close Joep1957]

Thanks to all for replying. It's certainly answered my question! Cheers

[AB's 97 Junior Member Find all posts View Profile Close AB's 97]

Yep mine does the same as what Ian mentioned...Although have noticed that it doesn't do it when I run premium fuel. It will just slowly gain the speed instead of revving it's guts out like it usually would when running on normal 91 unleaded. (referring to cruising up the hilly section southbound on the Hume highway in Vic).

[brissy Member Find all posts View Profile Close brissy]

Yes ours does it too , on large hills i try to cancel it

[ratsack Member Find all posts View Profile Close ratsack]

Would a lock up converter fix this?
This is where I miss having a manual. Manual on the high-way (or some option to lock into a gear) would be awesome.

[glen_ep Addicted PP Member Find all posts View Profile Close glen_ep]

Would a lock up converter fix this?
This is where I miss having a manual. Manual on the high-way (or some option to lock into a gear) would be awesome.

A lock up switch won't prevent the cruise control from kicking down into 3rd, actually, it'd probably exacerbate the situation, as it won't be able to do the initial torque slipping in top gear, so it'll jump straight down to 3rd. The cruise control electronics are the issue, as they insist on the set speed with little variance.

BTW I installed my own torque converter lockup switch one year ago and have found it useful on sand, to prevent the TC from slipping and creating excessive heat. I get up to speed and lock it in 2nd gear, 2,000 RPM and cruise from there. I didn't try this before the supercharger so I don't know if NA can maintain the 2,000 revs on sand (note, you cannot TC lock in 1st). I've never found the switch useful on highways - it's unnecessary, I don't like the way it acts and I'm always scared I'm going to blow the transmission. However, I never tow, and apparently these switches are put to best use when towing.