Borg Warner 3spd. Not changing gears properly?

[JT_1994]

I'm not sure what is going on, but something with my gearbox (Borg-Warner 3spd Auto) doesn't feel quite right; I was hoping somebody could perhaps give me some ideas for probable culprits before I get it checked out by a trans shop and become too temped to change it over to something a little more 'performance oriented'... Or go broke getting it sorted..... Or both!

It has a mechanical kick down, with a steel cable linkage attached to the throttle at the carb, which has already been adjusted properly..


I say it's not quite right because...
Off the line (at a T intersection for example) when I get off the brakes to set off it's like it's in 2nd and as my foot goes onto the loud pedal, it kicks down to 1st, then when speed goes up (and foot comes off the loud pedal) it changes back up to 2nd..
Also...... Or?
It doesn't seem to kick down over about 35mph unless I shift manually into "1st" and doesn't feel like it ever goes into 3rd..
Either that or the change between 2nd and 3rd is so smooth, and the difference in engine RPM is so small it's not noticeable.

Is it possible that it is changing through all 3 gears, but it's doing it at the right time so there are none left after 35mph?

For example, on the freeway while overtaking..
If I'm on the freeway behind a slow car, as I give it some gas and move right to overtake, the engine speed climbs but it doesn't actually change gear..

I know it's only got 3 gears, so I'm expecting it to sit at slightly higher RPM than a modern car so that will be a bit deceiving with a louder exhaust making it sound like it's revving harder than it should, but it just isn't changing through the gears properly... I'm thinking it's possibly the linkage at the gearbox end, or (God help me!) a problem in the box itself..?


.... Like I said, I'm not sure what's going on exactly, it just doesn't feel quite right...

[shaunp]

It would have a pretty low diff being a 6, I'd have a go at tightening the kick down up to make it kit back quicker. Or just take it to an auto guy. I'd also check the vac to the modulator.

[1966stang]

Is it a BW35 or the Ford 'Green' dot auto?

If it is the 'green' dot auto and you are putting it into what would be a modern "D" position you will only get two gears. It needs to be put into the 'green' dot position to get three gears (Ford did funny things in those days  )

Hope this helps in some small way.

[shaunp]

Is it a BW35 or the Ford 'Green' dot auto?

If it is the 'green' dot auto and you are putting it into what would be a modern "D" position you will only get two gears. It needs to be put into the 'green' dot position to get three gears (Ford did funny things in those days  )

Hope this helps in some small way.

It's 67 unless it's the wrong box it will be a 35

[GLENN 70]

Try backing the kick down off a bit , it might be too tight .

[JT_1994]

Diff ratio is 2.89:1 from memory..

No green dot on the shifter, just P-R-N-D-2-1...
Like this..



I'm going to try and explain this as well as I possibly can.... Although it doesn't seem like it could be the problem, it may be worth considering..?

Under the shifter bezel I can see a vertically mounted metal plate with 'steps' that lock the shifter into position, nothing strange about that.. It makes sense...

But those steps that determine the shifter position, relative to the bezel are a bit funny...
"1" is a high step and "2" is slightly lower so simply pushing the shifter forward will put it on "2", again, makes sense...
(I don't actually have to press the button to change from 1->2, all I have to do is push the shifter)
Pushing the shifter forward again SHOULD put it into "D", which is the lowest step..... (Same thing as 1->2, don't have to press the button...)

But, "N" shares that same low step.. So it is easy to accidentally put it into Neutral, but pulling the shifter back against the step (beside "D") does nothing. It's still in Neutral, despite the shifter being beside "D"..


The only forward gears I have to choose from are where the shifter is on either "1" or "2"..

It doesn't bother me so much that the shifter isn't quite aligned properly, I'm used to having "2" as Drive, but even if "2" is actually "D" it still doesn't seem to be going through the gears properly..

It's 67 unless it's the wrong box it will be a 35

I have a reciept from a SA wrecker that says the previous owner replaced the engine, trans and diff...
Pre-Xflow 250ci I6, Borg Warner auto (don't think it names the actual model) and a Borg Warner Diff.
Reciept says the g-box and diff came from an XY while the motor was from an XB..

Try backing the kick down off a bit , it might be too tight .

I'll have another look at the kick down for sure, but it looked fine when I put it all back together, judging by the photos pre-disassembly..

[shaunp]

If it's from an XY it's 35 or a C4 if it was optioned with a heavy duty trans. All QLD police 250 falcons were C4.

[JT_1994]

I distinctly remember seeing "Borg Warner" cast into the housing when it was last up on my mate's hoist, so I guess it's a BW35..

[GLENN 70]

1st, i hate std mustang shifters when the slide gate wears a bit ,hate hitting the big N . It may take two people to see whats going on ,one under the car checking that its going into each gear spot ,the other at the shifter to make sure its correct up top .It doesnt take much to be out and that will cause a problem .

[GLENN 70]

Well did you back off the kick down or a least adjust it ,and check that the shifter was aligned with the box from park down to 1st .

[JT_1994]

I found some quiet roads and adjusted the kick down, didn't take too much fiddling, it now feels much better but there are no gears after 45mph (goes into 3rd before 45mph), which I guess is probably just a consequence of having a 3spd auto..
It takes off nicely and changes through the gears both up and down smoothly...
When I upgrade the engine I'll probably get a 5spd manual, but for now the auto is working alright.

It doesn't feel like it's revving too hard on the freeway, and passing the noise barriers the reverb is awesome;

Shifter still isn't quite aligned, but that'll be a job for another day..

[GLENN 70]

It should kick down at 45mph ,if you think it changes too quick from 1st into 2nd and top you might have to adjust the modulator .If its adjustable ,you take the hose off and with a very very small flat blade screwdriver turn it 1/4 turn in or out and see what happens .This will change the shift points but only a 1/4 turn at one time .

[JT_1994]

I don't know if the modulator is adjustable or not, to be honest I don't even know what it looks like, or where it is....

It isn't slow to accelerate after 45, the engine still builds up revs. It's just already in 3rd by the time I'm doing 45mph.
Like I said though, it's working and changes smoothly so I think it'll be alright, I don't drive it everyday anyway..

[GLENN 70]

  thats fine ,its all a part of learning on these old cars  One day if you have the car jacked up have a look at the box and on one side  you will see a thin hose coming down from the engine and going onto a gold color thing ,thats the modulator if its got one .

[JT_1994]

I've had it on a mate's hoist a few times before, didn't really look too closely at the trans other than to make sure nothing was leaking..

Is it just a rubber vacuum hose?
The vacuum hoses all connect up within the engine bay..
One for the brake master cyl. and there's one for a valve on the rocker cover.

[GLENN 70]

There should be a small vacuum rubber hose coming off a vacuum post going down the back of engine then into a steel line then onto another rubber vacuum hose with a bend going onto the vacuum modulator on the lower side of the box .The steel line may have been changed at some time to a rubber hose .

[peter9231]

Hello,
If it is a Borg Warner 35 it wont have a vacuum modulator at all.
The cable is the throttle modulator and forced downshift (kick down)  combined.
You should not set this cable out of factory specs or you can damage the transmission.
The other item to control upshifts in a Borg Warner is the governor, this is located inside the extension housing.
If the governor is playing up it is either sticking or full of debris from a worn out transmission.
Can you take a photo of the trans for a positive ID.
Peter.

[sms777]

My two cents may offend some so please be gentle.
If it's a BW35 remove carefully and put in recycle bin even more carefully because you may damage all that 20 cents worth of it. Replace it with correct C4 as per manufacturers specs with correct kick down linkages and problem solved.
Cheers. 

[JT_1994]

I dare say it's a BW35, I did a bit of reading and it would appear that steel cable linkage on the throttle is the modulator / kickdown.
Unfortunately though, with limited space it is difficult to get the car high enough to take even decent photos, but it is definitely a BW gearbox.. I remember reading "Borg Warner" on the casing.



Swapping the transmission, (or much of the driveline at all for that matter) is not really viable just yet..
I go back and forth between swapping the 6 to a V8 and really tricking the 6 up with multi-carbs, a new cam, and lots of other go-fast bits.. So I'll have to figure out what I'm going with engine wise before I can think too seriously about what I'll do with the gearbox...

[peter9231]

First thing to check is the cable operation.
Disconnect from carbie end.
Pull the inner cable that connects to carb linkage, it should pull out smoothly and return by itself.
If the cable is not smooth in operation or does not return it needs to be replaced.
Peter.