Hi all,

It's been quite some time (probably Feb/Mar of this year) that I have posted or replied to any posts. I simply don't drive the Jag in the summer being that I have a motorcycle and run that until I can't bear the chill in the mornings. And that time has come again here in the NE. So I insured and registered the Jag again. It sat since last Feb when I blew the transmission. I sourced a replacement for $400, installed it, but never really got around to testing it out and making the fine adjustments (it was not registered or insured). Now I am trying to drive it and having some issues.

The one I'd like to discuss now and hopefully get some direction on is the late up shift to third gear, and consequently, the early down shift to second. The car shifts from first to second at moderate pedal pressure/acceleration at a reasonable speed/rpm. But the up shift from second to third takes stomping on the pedal, accelerating to a considerable speed, letting off the pedal and it'll shift. Then on decelleration it'll down shift way to early.

I have attempted to adjust the front band through the access panel and the rear band from underneath the car. (whoever thought that access panel would be big enough for adult hands needs to be fired!) And the keickdown apparently needs to be between 0.5 and 0.75 mm to the crimped on sleeve?

Any positive help would be appreciated.

 

Was this a used Transmission? If so, you got a bad one. Time for a rebuild.
Was it rebuilt? Pretty cheap is so. but if so then it could be the filter is plugged with assembly lube.
that's my 2 cents.

 

Thanks Amaezing!

Not good news... It was apparently rebuilt and had been run in a Ser 3 XJ6 until that car rotted so much that it went to the scrap heap. The tranny was pulled and was sitting in the shop's storage warehouse. I got a line on it from a friend who was employed there for a short while. Seemed a good price for a rebuilt transmission to me too. But couldn't pass it up.
Could it simply be a clogged filter screen? Not letting the fluid pass to the neccessary parts of the valve body? If so, that's an easy fix with a drain pan, 10 mm and can of brake cleaner. And keep everything clean and pour the fluid back in... Perhaps not... Fresh fluid!

 

That's my cheap guess. If your going to reuse the fluid, I suggest straining it with an old rag or a micro screen.
Your right about it being very easy as you described, but you also have the big nut that hold the fill tube in the pan.
The band adjustment doesn't do anything for the symptoms you described.

 

Thank you amaezing, I will try that, hopefully this evening. And I look forward to having anyone else weigh in with their vast wealths of knowledge!

 

My suggestion is to study the architecture and function of that box.
I am only vaguely familiar with it. It is basically a planetary gear system.
My first Model T ford had a rudimentry version.


First, second and reverse are controlled by bands that clamp on drums.


Third is by a multiple disc clutch. These can wear and be sluggish.
Or, more likely is the "control" that decides when to engage the clutch.
And what mechanism does the engagement.


That is my primer on diagnosis of anything..


Carl.

 

Hi all,

An update:
I went the route of changing the transmission filter. What a PITA that was! And to no real, tangible improvement. It now shifts into third, at high revs, but not as high as before. Sometimes I can coax it into third by "shifting" into second and tossing it back up into drive. It will sometimes shift into third, but not all the time, especially if I'm on an upslope or putting my foot into it. Plus, when running in third, and putting said foot into it, the car will want to shift into second (as it should) to compensate for the acceleration/load, and it slips. So irritating.
Before I decide that the replacement transmission is indeed a POS, does anyone know if it's simply a matter of adjusting, perhaps the cable linkage that goes from the shift handle to the gear selector? And that damn kick down cable... does anyone really know just how much "pre-tension" should be on the cable as adjusted by the nuts at the bracket?

Thanks for your help.

 

Also, if I go the route of yet another transmission, would it be best to have a shop rebuild the one I have? Or try to source another one outside? There is a gentleman that advertises on eBay for certified rebuilt Borg Warner T66 transmissions. He is located in Newnan, GA. Does anyone have any experience with him or his product/warranty?

Thanks,

 

It's not really a kickdown cable in the purest sense, although it does control kickdown. But it also controls the regular shifts as well. Many would call it a "TC Cable"---throttle valve cable

Anyhow....

The best/most correct adjustment is made using a pressure gauge....which only a trans shop would have.

So.....

Most rely on adjusting the cable as illustrated in the Jaguar manual where you adjust the nuts to get a specified gap (.015" I think...not sure) at the end of the cable. That is, the gap between the end of the threaded portion and the abutment where the cable goes thru. Maybe someone can post a pic out of the manual....a picture speaks 1000 words.

This might be called a 'base' adjustment. You can go forward/backward a bit to fine tune the shifts. But, there IS some risk. Go to far and you risk damage. A quarter turn can make a pronounced change in shifting.

There's also an internal adjustment used when assembling the trans but we obviously won't be going there at this point.

Also, have you tried adjusting the bands?

Cheers
DD

 

If your mechanically inclined then the rebuild is real easy. I did my own and it was real easy, been awesome ever since. Almost 6 months now and about 6k miles. I did it for less than $300. well maybe $350(I don't keep receipts)

 

T66 is easy rebuild. I add a drain to the pan on changing fluid. Most shops can rebuild as kits are available because of the multitude of cars using this tranny. when changing fluid, did you clean valve body?