BW35 problems

John75

New Member
WorgWarner 35 trans with around 45k mi. Pulled pan and everything looked like new. Installed tranny in a '63 series III. A short road test seemed ok, after about 100 highway miles the trans extremely overheated and spewed fluid all over the road and parking lot.

Back on the bench (couldn't find anyone locally willing to look at it) Couldn't find any major areas where the fluid escaped. There was light debris in the pan and aluminum film inside the torque converter - sent the converter to be rebuilt (rebuilder said needed parts).

Got a major rebuild kit. Took everything apart, all the seals & clutch plates looked like new but I changed them anyway. The only thing noticeable was the spring plate in the front clutch was broken in 4 places. Rebuilt and adjusted the front & rear servos and kichdown cable to book specs.

After installation the car will move on a level surface but couldn't even pull itself up my steep driveway in D1, D2 or reverse. It acts like standing on the brakes while giving gas in gear. The engine bogs down and the car won't move. The brakes are adjusted and the car drifts out of gear.

Took everything back apart and the only thing found was the sprague (one way) clutch which did work one-way on rebuild now spins both ways (on order).

BW35 manuals give great info. but I'm totally dumbfounded as what to do.

I welcome any and all suggestions and comments.
 
Sounds like that there's something operating inside the box when it shouldn't be. Out of gear it's not causing a problem, but engaging gear causes those components to apply and that combination could boil the fluid in the converter, throwing it all out. It's just like running a constant stall test. Trouble is that now that the box is dismantled there's problems trying to what was applied when it shouldn't have been.
Front clutch diaphragm springs are broken in about 3/4 of the boxes I've dismantled.
 
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One discrepancy in what you say, you mentioned D1 and D2, a P5 only has a five positive selector, PRNDL, no D1 or D2.
 
I noticed something else, you say the one way clutch spins both ways now, which you realise is a problem, so I'd be looking for some way that has been broken by other components working in an incorrect combination.
 
I noticed something else, you say the one way clutch spins both ways now, which you realise is a problem, so I'd be looking for some way that has been broken by other components working in an incorrect combination.
What should I be looking for? So far everything I looked at including the front clutch (diaphragm spring) seems fine.
The thrust washers seem to be wearing.
 
You have two clutches two bands and the UDC, look for signs that one has been stuck on, ie permanently engaged. The problem you have is that normally you would diagnose that by driving the car which at this point you can't. Plus because it's not possible to road test it it could be a different fault altogether.
 
I just love the way Harveyp6 can unpick a problem with a BW box or basically any P6 problem. We have quite a gift with this wonderful man on our team.
 
You have two clutches two bands and the UDC, look for signs that one has been stuck on, ie permanently engaged. The problem you have is that normally you would diagnose that by driving the car which at this point you can't. Plus because it's not possible to road test it it could be a different fault altogether.
My "road test" was 50 feet (as far as the car would go up my steep driveway in R, D, or L).
 
My "road test" was 50 feet (as far as the car would go up my steep driveway in R, D, or L).

50 feet isn't going to give you much chance of finding out what's going on, but if you know that it seems to be unable to drive then there's definitely a problem somewhere, but you won't even know what gear you're in. I can think of things that would cause that but not necessarily things that would boil and throw out all the fluid. That's normally the converter overheating, either a faulty converter, or something making the converter constantly stall. (A permanent stall test)
Plus I haven't got the opportunity to look at all the parts that you have in front of you.
 
50 feet isn't going to give you much chance of finding out what's going on, but if you know that it seems to be unable to drive then there's definitely a problem somewhere, but you won't even know what gear you're in. I can think of things that would cause that but not necessarily things that would boil and throw out all the fluid. That's normally the converter overheating, either a faulty converter, or something making the converter constantly stall. (A permanent stall test)
Plus I haven't got the opportunity to look at all the parts that you have in front of you.
The boil and throw out all the fluid was before the rebuild. After the rebuild, the test run only lasted under a minute because the car wouldn't go up a steep driveway (nothing getting warm yet).
One thing different was the two steel sealing rings (picture marked in red) broke and I put a couple nitrile O rings in place of them.
I can't find the rings anywhere except in a rebuild kit.
 

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The rings you mentioned used to be metal, Teflon? But later kits had a split plastic square section ring, which I always thought were more likely to become dislodged on assembly.
Looking at the rear servo I can't see a spring. (AKA the mousetrap)
(Unless it's a REALLY early one with a coil spring inside it, and I haven't seen one of those for decades. I should think they're a collectors item by now)
 
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There is a coil spring inside it. I took it apart on initial rebuild and replaced the seals.
Do you know where I could find the steel or split plastic square section rings without buying a complete kit?
 
That's a very old servo then.

Two places for parts, but both in the UK.

JPAT.co.uk

Vanmatic

JPAT show all the parts individually and will sell you as many or few as you need.
 
Looks like vanmatic only do parts for modern boxes now.

JPAT still list all parts for the BW35 individually, including three types of the rings you want.
 
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