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No compression at first?

2383 Views 8 Replies 2 Participants Last post by  umitbat
Hi
Today i noticed that when i lift off at first-manual mode- there is no compressipn as it is at neutral.
When i touch the gas pedal after hesitation revs com to normal,then again no compression when i lift off.
When i select 2nd no problems,com?ression normal.
Any comments?
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I assume by 'compression' you mean overrun braking (i.e. the vehicle driving the engine under no fuel so it behaves as an air compressor absorbing power)?

You would expect the LBC clutch to override/bypass the 1st gear sprag clutch in 'manual' mode. The LBC clutch is also used in reverse - are you having any problems with reverse?

Phil
Exactly;it slips under load at R(uphill).
Great info thanks,Phil.
Solution?
Could be the Low & Reverse Clutch itself that has a problem (hydraulic leak?) or maybe the Reverse Lockout Valve (which is there to prevent reverse being selected at speeds above 5mph) is being incorrectly activated due to a fault with the TCC/PWM solenoid valve - which would have a similar effect (i.e. stops Low & Reverse Clutch being engaged).

Is it any better when the fluid is cold rather than warm or does this make no difference?

Phil
Hi Phil,
It climded backwards when cold.It did not slip and climbed well at 1500rpm.
First seemed same,but i have try again tomorrow to be sure.
Thanks again.
It did not slip this morning too.
First acts like neutral when lift off even when cold.
If you take your Range Rover to a dealer or independent they’ll tell you that you need a new transmission (stock answer as they’re incapable of fixing it).

I think you need to find a transmission specialist who will start with the simplest/cheapest solutions first as they carry out their diagnosis. This may be something along the lines of :

1) Check fluid level
2) Check TCC solenoid valve filter for blockage
3) Test function of TCC solenoid valve (replace?)
4) Remove valve block, clean and check function of Reverse Lockout Valve

I think you need to bear in mind that, unless you’ve already had it replaced, it’s possible that the torque converter lock-up clutch lining has started to disintegrate (a common fault on the 5L40-E) and this has contaminated the transmission fluid and caused the solenoid/valve sticking problems. They should be able to get an idea of this from the state of the fluid.

If this still didn’t provide a solution the transmission would have to be removed and stripped to check the low & reverse clutch (plates, seals, etc.).

Phil
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Fluid level is ok;was changed 5000miles ago.It was black without any metal .The new fluid also was black when we checked it.
A specialist also asked me to check selonoids also.
Converter was not changed.
Update on situation:The car is still running no other slips other then R.
Since the situation is stable is it more likely to be selonoids other then clutc-pads?
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