Re: TH400 Jaguar application

[Thomas Alberts <talberts@aero.odu.edu>]

> At heavy throttle my XJ-S H.E. currently shifts into 2nd at 20 mph and into
> 3rd at 40 mph, compared to factory specs of 45 mph for 2nd and 60 mph for
> 3rd. The modulator only allows adjustment of 5-10 mph. The dpo had the
> transmission rebuilt by an expensive speciality shop, who did install a high
> performance sprag without the dpo's knowledge. At this point it is my best
> guess that they also replaced one or more of the calibrated parts with non
> ZV calibration parts. Does anyone know the specifications (part numbers) for
> the ZV calibration?

While your assumption is possible, it seems pretty unlikely to
me.  Normally one would not have much reason to go take a valve
body or governor from another transmission during a rebuild.  My
guess is that your vacuum modulator is not working, or perhaps
just barely working.  The claim (which I guess you read, and I don't 
doubt) that the modulator only allows adjustment of 5-10mph does not
support the conclusion that the problem is something other than
the modulator.  I believe the modulator and the detent circuit
are the only things that overide the governer in determination 
of shift points.  If the modulator is totally malfunctioning,
then you will get shift points like as if you are always operating
under light throttle, which sounds like the behavior you describe.
Replacing the modulator is one of the easiest things you can do
to a transmision.  Might be woth a try.  

I'd be pleased to hear the opinion of anyone more knowledgeable
than I on what I have just written.

Thomas E. Alberts

---

• Prev by Date: Rover V8 For Sale at Norristown Flea Market
• Next by Date: Rover V8 Holley FS at Norristown
• Prev by thread: Re: TH400 Jaguar application
• Next by thread: Re: TH400 Jaguar application
• Index(es):
  • Main
  • Thread