Did Bristols modify the Torqueflight

[Roger Morrall]

I understand the torqueflight always had full throttle 3 - 2 kickdown, part throttle 3 - 2 kickdown was only introduced in the early 70s when it was perceived to be lagging behind Ford and GM in respect of this feature. I’ve no idea when this might have been introduced into Canada.

But talk of 3-2 kickdown and aftermarket mods doesn’t address my question, which I’ll rephrase.

How did it come about that Chrysler drivers equipped with the torqueflight can select 1st and and the gearbox will engage 1st as soon as their speed drops below 30mph, giving all the advantages of engine braking from that point to virtually standstill, whilst when Bristol drivers equipped with the torqueflight select 1st the gearbox will only engage 1st when the car is already practically at a standstill?

(Only once the Bristol driver has virtually stopped and selected 1st will excellent full engine braking be available whilst he takes the speed up again as far as revs allow whilst remaining in 1st. If revs don’t allow and he changes up to second he’s back to square one and has to virtually stop again before the gearbox will engage 1st)

It strikes me as a very odd state of affairs

[David C]

Which model are you referring to, Roger?

I don't recall this issue on my 410. The manual gives maximum change down speed to 1st as 30MPH and if my memory is correct it would indeed select first from that point.

[Kevin H]

The earlier iron clad Torqueflite A-466 used on the 407 and 408 Mk1 had kickdown just the same as the 411 with the A-727 Torqueflite, (the description of the kickdown function is exactly the same in the 411 Owners Manual).

Below 29mph from either 2 or D(3) it will kickdown to 1st. Between 29-60 mph it will shift from D to 2.

In both cases kickdown is actuated by pressing the accelerator pedal to the floor stop.

I don't believe any of the V8 cars up to and including the 411 had part throttle kickdown (PTK).

It appears from this thread on a Mopar forum that PTK was introduced in 1971 for the A-727. The A-904 Torqueflite had PTK from 1967, but I don't think Bristol used the A-904.

It's also clear that PTK requires a different transmission valve body, so any talk of Bristol deleting PTK is yet another Bristol myth.

[Kevin H]

Something to bear in mind is that these transmissions may not behave today how they were meant to behave, if they haven't been maintained properly, including periodic adjustments to kickdown, bands, pressures etc. This can cause the transmission to hang onto lower gears too long or fail to shift down at the correct speed.

Also some may have been modified with an after market shift kit.

[Kevin H]

Originally Posted by Roger Morrall

How did it come about that Chrysler drivers equipped with the torqueflight can select 1st and and the gearbox will engage 1st as soon as their speed drops below 30mph, giving all the advantages of engine braking from that point to virtually standstill, whilst when Bristol drivers equipped with the torqueflight select 1st the gearbox will only engage 1st when the car is already practically at a standstill?

Roger, which Chrysler are you referring to and which Torqueflite transmission does it have?

At what speed are you suggesting that Chrysler drivers select 1st gear?

In most, if not all automatics, you can't safely select 1st gear if you are travelling significantly faster than the max speed for 1st gear, because it will actually shift into first gear. In manual override mode the transmission won't 'wait' until the speed is low enough for 1st gear - if you select 1st, it will shift into 1st.

Are you sure you're not thinking of 2nd gear in a three speed auto?

If you want engine braking with a three speed Torqueflite A-727 (or an A-466) selecting 2 is the way to go. In town driving you're probably better off driving around in 2nd than D; the car will be much more responsive

[Roger Morrall]

David C, Kevin H

Thanks for your responses

Mine was a 410, built 1968.

Yes, it would kick down into 1st gear if the pedal was floored at an appropriate speed, entirely in accordance with the handbook - that is not the issue I’m trying to get my head around.

When 1st gear was selected on a trailing throttle it would only engage 1st gear after I’d brought the speed down to about 6 mph on the brakes. This is not in accord with the Chrysler literature, which indicates that when 1st is selected it should engage 1st when the speed is down to about 30mph. My recollection is that the Bristol drivers handbook did not match the Chrysler literature in this regard.

I did not become aware of the Chrysler literature on how the torqueflight was expected to perform until after I sold the car on in order that it could enjoy the travels it had become accustomed to. I am somewhat curtailed in regard to long distance travel now but my interest in things Bristol remains and my curiosity is aroused.

The car was as well maintained as it could be, by BCS, SL-J and ACCS, none of whom ever suggested that the gearbox characteristics weren’t in any way up to Bristol standards. It bore the original engine and gearbox numbers. ACCS rebuilt the gearbox after the torque converter failed. I owned it for 20 years and it took us as far as Morocco, Transylvania and Montenegro and most points in between, very often the only V8 on Geoffs Travels, so I knew it inside out.

Roger

[David C]

I can't be sure but I think I remember that my 410s would change down to first if the floor selector was used at around 25MPH. I will have to check but haven't got the car at home at the moment.

It looks as though it is possible to convert early Bristol Torqueflites to part throttle kickdown if you can find the kit:

727 3-2 Kick Down Module (1966-69) - A&A Transmissions

[dwomby]

FWIW, my 408 has a 1962 Torqueflite that was fitted here in the USA. I don't know if it was modified from standard at any time but it definitely has a kickdown function.

David

[Roger Morrall]

David C - I’d be most grateful if you could remember to check this when you do have the car back

[Kevin H]

Originally Posted by dwomby

FWIW, my 408 has a 1962 Torqueflite that was fitted here in the USA. I don't know if it was modified from standard at any time but it definitely has a kickdown function.

David

David, I'm puzzled by your comment. Why was a 1962 Torqueflite fitted to your 408 in the USA? What transmission did it have beforehand?

The 408 (Mk1) for the UK market left the factory with a Torqueflite (A-466), which incidentally had kickdown in 2nd and D (3rd), just like the later A-727.

[dwomby]

Originally Posted by Kevin H

David, I'm puzzled by your comment. Why was a 1962 Torqueflite fitted to your 408 in the USA? What transmission did it have beforehand?

The 408 (Mk1) for the UK market left the factory with a Torqueflite (A-466), which incidentally had kickdown in 2nd and D (3rd), just like the later A-727.

Hi Kevin, my car was exported to USA in 1992 after body restoration in UK but without an engine or transmission. I have spoken to the then owner who said Tony Crook found that car for him and it had no engine or transmission when he bought it for restoration. He left it that way as he reasoned import duties to US would be less and the engines and transmissions would be plentiful and cheaper here.

After arrival here, the car was fitted with an appropriate '62 pushbutton TorqueFlite (donor unknown) but with a 1978 360 from Dodge Monaco (modified with a performance camshaft and intake manifold).

David

[Kevin H]

Originally Posted by David C

I can't be sure but I think I remember that my 410s would change down to first if the floor selector was used at around 25MPH.

As one would expect at 25MPH or even 30MPH.

I'm not sure what happens if you try to do it at higher speeds. I have vague memories of accidentally momentarily selecting first gear on an A-727 torqueflite at higher speeds and I think the transmission would still shift down immediately, which puts the transmission at risk of damage.

[Kevin H]

Originally Posted by David C

It looks as though it is possible to convert early Bristol Torqueflites to part throttle kickdown if you can find the kit

Trans Go made one as well.

[David C]

I'm told the TransGo item is no longer available but I can't confirm or deny.

[Kevin H]

Originally Posted by Roger Morrall

When 1st gear was selected on a trailing throttle it would only engage 1st gear after I’d brought the speed down to about 6 mph on the brakes. This is not in accord with the Chrysler literature, which indicates that when 1st is selected it should engage 1st when the speed is down to about 30mph. My recollection is that the Bristol drivers handbook did not match the Chrysler literature in this regard.

Roger,
What was the Chrysler literature you refer to?

Kevin

[Connoisseur]

"The Chrysler Torque-flite 3-speed automatic transmission was likewise altered to meet Bristol’s exacting requirements. The part-throttle kick-down has been eliminated, as not giving a sufficiently smooth action, and the full-throttle kick-down adjusted to suit the lower weight of the Bristol against that of a massive Chrysler sedan."