Downshift Jerk from 2nd to 1st
#1
Downshift Jerk from 2nd to 1st
2005 LR3 NAS, JA-V8 petrol, in tip top shape, with all sorts of repairs already done - but, there's a persistent issue with the transmission giving a bump when downshifting from 2nd into 1st. So, imagine coming to a standstill, perhaps at a traffic light, and when it comes to drop from 2nd into 1st gear, there's a forwards bump.
I've researched, and I've checked the fluid level with thermometer (flushed the gearbox recently, too) and I've loosened the cable which could be binding... but I'm unsure I did that right. I basically loosened the two bolts and greased, and re-tightened.
What could I do to fix this annoying jerking?
I've researched, and I've checked the fluid level with thermometer (flushed the gearbox recently, too) and I've loosened the cable which could be binding... but I'm unsure I did that right. I basically loosened the two bolts and greased, and re-tightened.
What could I do to fix this annoying jerking?
#2
I would start with software updates. Its unusual for a car to go 14 years and not have them done, but I certainly would not hang any parts on the vehicle until I knew the software was current.
There is a TSB for this very issue
TRANSMISSION DOWNSHIFT FROM 2ND TO 1ST GEAR IS HARSH
Situation:
A customer may report a concern that the gearshift is harsh and results in a thump or bump when the transmission shifts from 2nd to 1st gear. This condition occurs when the throttle is applied following a deceleration where the vehicle is slowing to a near stop. This condition can be intermittent and can vary depending upon the amount of throttle that is applied.
Action:
Should a customer express this concern, verify the condition and refer to the Repair Procedure below to update the Transmission Control Module (TCM). Check and, if necessary, update the Engine Control Module (ECM) software also.
There is a TSB for this very issue
TRANSMISSION DOWNSHIFT FROM 2ND TO 1ST GEAR IS HARSH
Situation:
A customer may report a concern that the gearshift is harsh and results in a thump or bump when the transmission shifts from 2nd to 1st gear. This condition occurs when the throttle is applied following a deceleration where the vehicle is slowing to a near stop. This condition can be intermittent and can vary depending upon the amount of throttle that is applied.
Action:
Should a customer express this concern, verify the condition and refer to the Repair Procedure below to update the Transmission Control Module (TCM). Check and, if necessary, update the Engine Control Module (ECM) software also.
#3
Yes, good advice. I was fearing that, actually LOL - scared of the dealer...
I found the ZF trouble-shooting manual, and it says 1. check fluid level, 2. check binding of cable, 3. update software...
How would I go about the cable binding? I didn't really understand why an outside cable and lever would affect an internal downshift, and I didn't have any procedures to follow, other than remove the bolts and spray some grease around the moving parts, and then put it back together feeling like I'd wasted time... so maybe I could try that again properly before going in for the software update?
I found the ZF trouble-shooting manual, and it says 1. check fluid level, 2. check binding of cable, 3. update software...
How would I go about the cable binding? I didn't really understand why an outside cable and lever would affect an internal downshift, and I didn't have any procedures to follow, other than remove the bolts and spray some grease around the moving parts, and then put it back together feeling like I'd wasted time... so maybe I could try that again properly before going in for the software update?
#4
#6
#7
Is it possible to check what version software is installed to see if its been updated previously ? I have the occasional thump but my main issue currently is a failure to downshift from 3rd to 2nd or first and then when load is applied a transmission fault special programs off message on the dash - no fault codes logged though ?
#10