XJ8 Transmission
#24
02-14-2013, 11:15 AM
Veteran Member
Nothing you have described seems like particulary out of order. These transmissions tend to hold lower gears when coasting sometimes.... ( I guess you were expecting a 4th gear upshift when at 70mph you let off).
My bigger worry was it not upshifting upon acceleration.
Take care,
George
My bigger worry was it not upshifting upon acceleration.
Take care,
George
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Got a Jaguar Jones (02-15-2013)
#26
02-19-2013, 11:35 AM
Senior Member
Hi Jaguar Jones,
I have not been able to solve the problem yet with the transmission. I still need to take the car to the dealer to do a reflash. The problem I still have occuring is only when accelerating at full throttle when I'm at speeds above 50 mph. The car will down-shift to build up speed, but when it's time for it to up-shift it will not catch the higher gear and only rev as if it were in neutral. The revs go up to about 4 to 5 thousand RPM. Only when releasing the pedal it will shift into the higher gear. (Please note that this problem occurs when sport mode is off. I have yet to try accelearting in sport mode). After I do the reflash I will check to see what George has mentioned below regarding a transmission fluid overflow. The other day I punched the throttle down to overtake some cars in traffic and the transmission shifted properly that time. I was surprised that it felt perfect and smooth, but I really should still take it in for a reflash. Anyone happen to know how much a reflash cost?
I have not been able to solve the problem yet with the transmission. I still need to take the car to the dealer to do a reflash. The problem I still have occuring is only when accelerating at full throttle when I'm at speeds above 50 mph. The car will down-shift to build up speed, but when it's time for it to up-shift it will not catch the higher gear and only rev as if it were in neutral. The revs go up to about 4 to 5 thousand RPM. Only when releasing the pedal it will shift into the higher gear. (Please note that this problem occurs when sport mode is off. I have yet to try accelearting in sport mode). After I do the reflash I will check to see what George has mentioned below regarding a transmission fluid overflow. The other day I punched the throttle down to overtake some cars in traffic and the transmission shifted properly that time. I was surprised that it felt perfect and smooth, but I really should still take it in for a reflash. Anyone happen to know how much a reflash cost?
Hi JagMan,
Just wondering if you rectified the problem with your transmission. I have the same car (2004 VDP), with the EXACT same problem, but no leaks, and fluid is full. I have owned the car for 6 months, now at 105,000 miles, and no other problems. Trans started acting this way about a week ago. Any info or pointers would be greatly appreciated.
Just wondering if you rectified the problem with your transmission. I have the same car (2004 VDP), with the EXACT same problem, but no leaks, and fluid is full. I have owned the car for 6 months, now at 105,000 miles, and no other problems. Trans started acting this way about a week ago. Any info or pointers would be greatly appreciated.
#27
02-19-2013, 03:50 PM
Veteran Member
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JagManBonano (02-21-2013)
#28
02-23-2013, 08:48 PM
#29
02-24-2013, 03:58 AM
Member
I found a guild to all sorts of gearbox problems
http://www.superv8.co.uk/wp-content/...ting-Guide.pdf
Have a look at page nine as these seems to discribe your symptoms.
Good luck,
Peter
http://www.superv8.co.uk/wp-content/...ting-Guide.pdf
Have a look at page nine as these seems to discribe your symptoms.
Good luck,
Peter
#30
02-25-2013, 10:31 AM
XJ8 Tranny fill plug
I am trying to verify/ top off a leaking tranny on an 2001 XJ8. Appears to have bad front seal. I don't know where the fill plug is at but if its on the lower front near the bell housing(I think it was a 19mm) then I am not able to remove it all the way because it hits the exhaust header with a turn or two left before it can be removed. Is this common to this particular model or am I trying to remove the wrong plug?
#31
08-25-2013, 08:17 AM
I still think there is a fluid, or a level problem. OR a mix of old and new fluid. Don't forget you don't get all the old fluid out with just a pan drain.
These transmissions are EXTREMELY sensitive to fluid variations. The trans will exibit symptoms with over / under fill conditions of less than 1/2 quart.
Yes a glass of transmission fluid can be the difference between a perfectly shifting trans and one that feels like its about to fall apart.
The usual symptoms with a zf6hp26 experiencing a low fluid condition, are rough shifts and slipping / jerking in low gears, especially when the trans is cold. It's most pronounced in bumper to bumper traffic type situations, I've had cars come in that feel almost like someone who doesn't really know what they are doing with a manual transmission is driving. Once they warm up they seem to shift OK.
What you describe to me though, the lack of an upshift until you release the pedal (Just how far up the rpm will it hold the gear?) is almost indicative of an overfill condition. Seems like someone rushed to fill it and didn't wait for the trans to warm up properly, pumped too much fluid in, and capped it. Too much trans pressure leads to an almost "hydrolocking" of the drums in the transmission. Releasing the throttle, and therefore lowering the pressure in the transmission momentarily initiates the shift.
Don't forget that the torque converter transfers all the power to the engine via hydraulic pressure. There is no mechanical link between the crankshaft and the transmission input shaft on an automatic transmission. Aka spinning the fluid almost like a centrifuge, with two fan shaped drums.
So before you go any further.
Just HOW long will it hold a gear? Indefinitely? Till Redline? Or just higher in the RPM's than you expected it to shift? Is the trans in sport or regular mode.
Next, can you engage each and every gear distinctly using the J-Gate shifter?
Let me know and we will go from there.
Take care,
George
These transmissions are EXTREMELY sensitive to fluid variations. The trans will exibit symptoms with over / under fill conditions of less than 1/2 quart.
Yes a glass of transmission fluid can be the difference between a perfectly shifting trans and one that feels like its about to fall apart.
The usual symptoms with a zf6hp26 experiencing a low fluid condition, are rough shifts and slipping / jerking in low gears, especially when the trans is cold. It's most pronounced in bumper to bumper traffic type situations, I've had cars come in that feel almost like someone who doesn't really know what they are doing with a manual transmission is driving. Once they warm up they seem to shift OK.
What you describe to me though, the lack of an upshift until you release the pedal (Just how far up the rpm will it hold the gear?) is almost indicative of an overfill condition. Seems like someone rushed to fill it and didn't wait for the trans to warm up properly, pumped too much fluid in, and capped it. Too much trans pressure leads to an almost "hydrolocking" of the drums in the transmission. Releasing the throttle, and therefore lowering the pressure in the transmission momentarily initiates the shift.
Don't forget that the torque converter transfers all the power to the engine via hydraulic pressure. There is no mechanical link between the crankshaft and the transmission input shaft on an automatic transmission. Aka spinning the fluid almost like a centrifuge, with two fan shaped drums.
So before you go any further.
Just HOW long will it hold a gear? Indefinitely? Till Redline? Or just higher in the RPM's than you expected it to shift? Is the trans in sport or regular mode.
Next, can you engage each and every gear distinctly using the J-Gate shifter?
Let me know and we will go from there.
Take care,
George
That sounds like what I feel in low gears. Where should I take the car for fluid check like you described? Just for FYI: first check under/o over fluid/ second: reflash? What is reflash? I just got a super clean 04 Vanden Plas w/114k mi. There two issues, one being the low gear jerk/slip mostly while cold as you described. The other being a weird intermittent navigation screen scroll after the logo screen display when starting car. Twice the screen continually scrolled from climate to audio during a 15 min drive. Nexttime I drove no scrolling, then scrolling on next drive again, very intermittent at this point.
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