Yet another thread on autoboxes

[roedmose]

I have chosen to open a new thread to help keep the overview, though this is somewhat related to other threads.
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As mentioned in another thread, my autobox gave up 3 weeks ago with screaming sounds. Despite this I was able to cover 100 miles with it, to get home.

I have earlier bought in a BW35 type 303 from a P6B, and this box should have been rebuild recently according to the seller. I considered ending the season early and change the boxes in the winter, but as I have a fear that the 'new' box might not live up to my expectations, I will not risk to be ready in the spring, just to discover that new box had errors as well.
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So I have just taken the old box out. Took a hybrid approach as I took off the exhaust, and separated everything from the inside of the car and lowered the box to the floor. That the box have to be separated from the bellhousing surprised me, as the 2 lowest of the bolts are almost impossible to reach. I can't see how I will get them tightened when the new box is installed, but we will see......
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Now according to my P6B manual the 303 is a revised box and the TC should also be revised. But from the outside it looks exactly similar. So my problem is :

1) Should I take of the old T/C and install the one that belongs to the 303 box. Risk is that I get imbalance to the drivetrain.

2) Or shall I keep the old T/C in place. Risk is that the phrase 'revised', covers over changes that will give me problems when installing or when taken on the road.


Any ideas anyone ?

I will keep this thread updated with my experiences in this exercise

[harvey]

In answer to question 1, the 303 was the best of the boxes fitted to the P5B & P6B so is the best box to have. It would be advisable to keep it matched with its own converter, if only because your old one may be full of debris from the faulty box.
I would be very surprised if you had vibration problems after doing this. If you were replacing with a recon g/box and converter you would fit a converter then.
Question 2, I don't think there is any physical reason to stop you fitting the 303 box to your original converter and bellhousing should you wish to.

I think the revisions to the converter were the removal of the cooling vanes on the outside of the converter and the removal of the cooling holes in the bellhousing.
The bellhousings can crack from these vents so better to fit the later type when you fit the converter. ( the 303 should have the later T/C & bellhousing )
Hope this is of help
P.S. Are the kickdown cables on both boxes the same length?
If not and your car had the long cable, I would advise getting the later throttle bracket, and using the 303's shorter cable.

[Keith - Portsmouth]

I think it is really important point that Harvey makes...
There is bound to be some debris in your old torque converter.

Also, it would be a good idea to flush out the pipes and cooler in the radiator to get rid of debris there.

Keith.

[harvey]

It's always a good idea to flush out the cooler whenever you're doing any auto box work
I knew I meant to add something else, thanks for doing it for me Keith. Not a lot of point getting all the debris out of the T/C and leaving the cooler and pipes full of it!

[roedmose]

Thanks for the input. As I got the 303 box I made sure that the kickdown-cable was included and reusable, as I know this is different. I even got the bracket at the carb side from the P6B as well. When I look at the arms where the cable is attached at the throttle side, they look exactly the same, so I intent just to keep the cable on the 303-box and plug it in at the existing bracket.
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Now I will let the project rest for a few days. I have to take of the oil-pipes as these were rotten and deterogated at dismantling. Though bend I think I can reuse the piping from the 303-box. I will blow the oil-cooler clean; tx for pointing this out !!

Frank, Denmark

[roedmose]

I installed the 303 box but it sounded awful when started. This was mentioned under the thread "gearbox refitting".
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I noticed a sligth "wrong feeling" when turning the flywheel with the heads of the four bolts that holds the T/C.
So box out and I could see small alloy-particles on the T/C. Removal of the bellhousing showed that the T/C could touch some re-inforcement-wings cast in the bell-housing. I was told that the 303-box, bellhousing and the T/C came from the same car, but this can not be the case. Phil mentioned some diferences on the T/C, so the late p6's with the 303 box must have a different T/C which is not the one, I became.
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Now I have 2 millimeters marks in the bellhousing, but I think that the particles can not have entered the T/C nor the box, so problem is solvable.
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So I think I have 2 choices :

1) grind away material in the 303-bellhousing, so that the T/C can find room.

2) Or install the old bell-housing as the depth is the same. The 303-bellhousing is, however, casted differently inside (why ?) and it misses these open holes that the old one has (why ?)

Any comments anyone ?

So those building in a 303-box take care !

Frank

[Phil Nottingham]

There were at least two different bellhousings so fit the one that does not foul the converter. Grinding away the other may not be good idea unless you are certain that it will not weaken it if the cast ing is different

[harvey]

Hi Frank, I would agree that grinding the bellhousing is not a good idea! Would it be possible for you to post pictures of the T/C and bellhousing so we can see what you've got?The holes are cooling vents for use with the early T/C.

[roedmose]

I found time today (again) to work on this gearbox install. After totally 5 times in and out, it finally went into place this week. The problem with the bell-housing was one time in-and-out, and the rest of the times was problems getting the oil-pump to settle in. It migth be a problem that in the week it is very late before I find the time to go to the shed, so I am often to tired.
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But today everthing was put together and no ugly sounds when started. But, but but : the old box was vary hard in the shifting and this is even harder and it shiftes to late in my opinion. I will try to tighten the kickdown cable up, to try to make it shift earlier, but I suppose that will not change how hard it shifts. A little frustrating as the box I acquired was recently overhauled and I had dreamt of shift as soft as ...... well, you know !
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Even 2 extra smaller problems. Just before coming to a hault, the box gives a loud CLOCK as it goes down into 1. I remember this being debatted on the old list, showing that many boxes had this ''feature'', so that is most likely something one has to live with. The last problem is that the scale on the gear-lever (P-N-R-D-2-1) does not match the arrow anymore. As I have reused the lever and its rod and it starts 'above' P and ends 'below '1', I have the feealing that the 303-box has longer travel on the selector arm. The R and D fits almost.
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If anyone has comments on making it shift earlier (and perhaps softer) I would be very happy. Ans if anyone has comments on how to make the scale fit after installing a 303-box, please help me.
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To Harvey and Phil :

When I look at the 303-bellhousing I would not have hesitated to grind away sufficient material to adopt the old T/C, IF the old bellhousing had not fitted. But you are both rigth that as it could be avoided by using the old bellhousing that was the best solution.
I will take a photo of the problem and update the thread in the week we enter.

Frank

[harvey]

35 boxes have a fairly harsh shift at the best of times. Harsh shifts, late changing up, and a CLONK when changing down into first, are all symptoms of the pressures being to high. The kickdown cable needs to be backed off, i.e. screw the outer cable back up towards the end of the inner cable, further into the bracket, bit difficult to explain, but you need to lower the pressures.
You won't ever get a really smooth (seamless) change with a 35 box
There should be no difference in the selector arm, check all the linkage and its adjustment. If you're still not happy fit the arm from your old box, and you will probably find it's just the same.
Final thoughts for the moment, don't use DEXRON fluid, check the linkage and its adjustment,get the correct fluid level, and lower the pressures a bit by adjusting the kickdown cable,doing the final setting on a road test.

[Phil Nottingham]

It does sound like the kickdown - has it got the later type on the end of the head as the bush usually disppears making proper adjustment impossible. Too high idle speed as well can cause clonking.


The boxes are supposed to be interchangeable so it may be just careful adjustment of the rod lengths also the bell crank at the front end of the linkage on top of the box can seize partially. The rod measurements are in the manual

Definitley no Dexron ATF

Mine is a rebuilt 303 and its very smooth on changing even on kickdown

[roedmose]

Tx Harvey and Phil. I will slacken the cable and see.
No I don't use Dexron.
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When and if the rain stops I will adjust and test. Rolling Stones is giving outdoor concert for 85000 people some 20 miles from here and it rains!!!!!
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For the rest of the adjustment of the rods, I will wait and see if the box behaves, as I will have to take off the covers again to adjust. And if the box does not get better, I will consider to try my third box; now that I am in the habit of box-swapping !! ;D

Frank

[harvey]

The boxes are definately interchangable, and the 303 is the one to have.
My use of the word "harsh" for the normal changes on the 35 box was perhaps ill advised,what I meant was you will always feel the change, but that's perfectly acceptable in my view. harsh should be reserved for the problem you've got here.

[roedmose]

Here I added a picture of a 303-bellhousing ("the late type") being subject to a "old type" T/C. Ran for 30 seconds !

i6.photobucket.com/albums/y216/roedmose/P0005394.jpg

Today I slackened the kickdown cable but no improvement at all in the shifting. The 303 box slams the next gear in as one can imagine a manual box that is shifted without clutch at random revs. I will try go to the opposite way and tigthen the cable even more as before just to see what happens. As the box is now, it is not usable. If I put the lever in "2" and start here and manually goes to "D" at the right time, the car is drivable. So I will take the rest of this season in this "manual way", and consider yet another swap in the winter. At this moment I even consider if summer holiday 2007 will be to UK again, this time with an autobox in the trunk, and get it overhauled "over there".

Frank , DK

[harvey]

If you do bring the box over to the UK, I can put you in touch with someone to overhaul it for you.

[Phil Nottingham]

It could be worth changing the valve body assembly from your old one - they easily removable after dropping the sump.

I did this once and the box performed faltlessly for many thousands of miles and never ever gave any more trouble while in my ownership - could still be going?

[roedmose]

Thank to Harvey for the offer ;D We will se when the spring comes, how far I have come.....
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To Phil. I think I will try your suggestion. Though I still have a 3. box ready, I will try it before yourr suggestion first, I assume. Must be easier than swapping boxes again.
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I looked in my P6 workshop manual under 303-boxes, and my box changes gear exactly at the speeds mention under "Hard throttle". But I do drive extremely soft !! 3. gear kicks in hard at around 55 Mph, but f I go up to 50 and releases the throttle, it will go up in 3. a bit softer and I can accelerate again !
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One last question : I assume that the T/C is totally irrelevant in this matter ? I still can't help thinking why my P6 workshop manual states that if one upgrade a P6B to the 303-box, BOTH the bellhousing and the T/C must be changed to the corresponding ones. I have learned (as per picture in prev. post), why one must let the T/C and bellhousing be matching, but as I think it will be much easier on a P6B to take the box out than it is on a P5B, I would assume that many people would just swap box and leave the bellhousing and T/C undisturbed. Why does the manual then state that they must be changed as well? To be short : No chance it is be the old type T/C that is disturbing my 303-box ? Have anyone else tried this combination ? The biggest frigth would be, IF I get the 303-box rebuild and install it with the same result because it is a T/C problem - That could wipe the smile of my face for several hours !!!

Frank, DK

[Phil Nottingham]

It does not sound like the converter more like the valvebody which the kickdown works

The later bell housing was introduced because the cooling vents were noisy - sone converters did have a shroud welded to them as well to assist cooling - see other thread as to whether this is needed!

[harvey]

The symptoms you have would indicate incorrect kickdown cable adjustment (pressures too high) If you have the box overhauled I would advise fitting a recon torque converter at the same time.
Incidently, I personally prefer to fit boxes to the P5B rather than P6b, because you don't need to disturb the exhaust.