Gearbox Kickback Issue
#1
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After completing a lot of work on the motor getting things correct I have noticed a definite problem with the gearbox, as stated on prior posts I will be going to a 5 speed manual but do not have time at present to this so I need the the old TH400 working.
The drama is that the kickback works fine, put your foot down and it kicks down but doesn't want to kick-up after that, it just holds that gear till you back off then kicks up. this is very annoying as it it will sit in 1st or 2nd and stay at 6-7000 rpm without moving until you depress the accelerator than it changes. I personally have had nothing to do with nor worked on any automatic cars, this is my first one and more than likely my last, where do I start looking? Is there a vacuum switch or is it cable driven? i can't see it being the clutches/bands in the box as it only has 130k klm on the clock.
any thoughts
After completing a lot of work on the motor getting things correct I have noticed a definite problem with the gearbox, as stated on prior posts I will be going to a 5 speed manual but do not have time at present to this so I need the the old TH400 working.
The drama is that the kickback works fine, put your foot down and it kicks down but doesn't want to kick-up after that, it just holds that gear till you back off then kicks up. this is very annoying as it it will sit in 1st or 2nd and stay at 6-7000 rpm without moving until you depress the accelerator than it changes. I personally have had nothing to do with nor worked on any automatic cars, this is my first one and more than likely my last, where do I start looking? Is there a vacuum switch or is it cable driven? i can't see it being the clutches/bands in the box as it only has 130k klm on the clock.
any thoughts
#2
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The drama is that the kickback works fine, put your foot down and it kicks down but doesn't want to kick-up after that, it just holds that gear till you back off then kicks up. this is very annoying as it it will sit in 1st or 2nd and stay at 6-7000 rpm without moving until you depress the accelerator than it changes.
The drama is that the kickback works fine, put your foot down and it kicks down but doesn't want to kick-up after that, it just holds that gear till you back off then kicks up. this is very annoying as it it will sit in 1st or 2nd and stay at 6-7000 rpm without moving until you depress the accelerator than it changes.
To clarify, this occurs only during kickdown? That is, under light/moderate throttle the transmission upshfits normally?
On the old 400s the most common culprit for 'no upshift' condition is a dead vacuum modulator....or the vacuum hose to the module is disconnected/broken/leaking. In my experience, though, this causes a problem at any throttle setting, not just during kickdown. Still, it merits investigation.
After that I'm inclined to suspect the governor, or a governor-related fault.
Cheers
DD
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Katoh (04-11-2014)
#3
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I think you may have knuckled it down for me Doug, I had a sneaking suspicion about the kick-down switch but I was not at all clear how the XJS was setup.
When get a chance not for a while now Ill put her up on the hoist and chase the hose up to the motor, if the hose is Ok I look at the switch itself.
Thanks again!
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