At 01:21 AM 6/1/98 -0700, Brandon Kasch wrote:
When fully warmed, it shifts into 2nd gear at speeds as slow as 5mph.
Also, it will up-shift and down-shift repeatedly under full throttle when
it should just shift into the next gear.
From experience, this sounds an awful lot like the fluid is low
(fortunatley, I haven’t had this experience in my Kitty, or the current
tranny in my Buick - but the prior one had a habit of leakage, which would
run the tranny low enough to cause a delay in pick-up when you’d first
start it if you didn’t watch the level). So, first thing, go warm up the
transmission, then check the fluid level.
I just browsed the trouble diagnosys section of my GM-400 service manual
(actually, the GM-400 transmission section from my Buick - a book almost
two decades older than my Jaguar, yet the two cars share the same
transmission), and this sounds like “LOW or HIGH SHIFT POINTS”
This is caused by any one of the following:
A. Oil Pressure
Engine vacuum - check at transmission end of the modulator pipe.
Vacuum modulator assembly vacuum line connections at engine and
transmission, modulator valve, pressure regulator valve
Feed holes restricted or leaking, pipes damaged or mispositioned.
Feed line plugged.
C. Detent Solenoid
Stuck open, loose, etc (Will cause late shifts).
D. Control Valve Assembly
Detent valve train.
3-2 valve train.
1-2 shift valve train / 1-2 regulator valve stuck (this would
cause a constant 1-2 shift point reguardless of throttle
Spacer plate gaskets - mispositioned, spacer plate orifice
holes missing or blocked.
Porosity; intermediate plug leaking, missing.
There are a lot of other diagnosys items, but I don’t have the time to
transcribe the manual here. The documentation should be readily available
at any American auto book seller.
This usually happens at about 5300rpm during a long drive.
Is this a 6 or a 12? 5300 rpm on my kitty would be scuttling you along at
I know the transmission is in good condition
because I had it rebuilt with high performance TCI parts less than 5000
Did you have them INSTALLED, or did you have the transmission REBUILT, or
OVERHAULED. There are differences. If you paid in the US$500-700 range
for the work (minus the cost of the TCI parts), then it should have been an
overhaul. If significantly less, you probably got yourself a filter
replacement and kit installation.
I am curently useing B&M trick shift fluid.
Some fluids can do bad things to some components like gaskets. Probably
not a problem here, as long as the shift fluid is FOR a GM auto trans.
the problem is due to excessive heat causeing the fluid to thin. I have
Why do you have excessive heat? Has the engine been overheating?
some sinthetic Red Line fluid that may elliminate the problem if it is what
I suspect. I am hessitant to try it because if any transmission work needs
to be done, they will drain my 90$ worth of fluid.
There has been mention of a “topsider” oil changer, which feeds a pipe down
through the oil dipstick and pumps it up through there. I suspect this
same product could be used for draining a transmission (IMHO, it is even
better suited to that, since transmissions have no drain plug).
Sean Straw '88 Jaguar XJSC 5.3L V12
Marin County, California '69 Buick GranSport 455 V8