Transmission / Overdrive: Power-shift, shifting sluggishly

[spokejr]

Here's the latest on 63R-2962.

For the last month she's actually been a daily driver!

Over the last few months she has been shown at the Pasadena Art Center's annual car show, had the opportunity to meet Bob Caser and others. It's been well received at the cars for coffee meets around Pasadena as well. To get her to this point I have had the carb and distributor rebuilt by Dave Thiebault, I have had the radiator recored and naturally all the hoses I replaced, even to the heater. The motor mounts are all new and even hot tanked the fuel tank. The one thing I sublet the labour on was mounting up the dual circuit master cylinder and bleeding the brakes. We found the rear cylinders were rusted up and rebuilt the slave cylinders as well as replaced the hoses. And yes, I did figure out what was wrong on my power steering rebuild. Put the pressure valve in backwards in the pump

Now for the next problem. The trans doen't want to shift from second to third until the car has gone for about a mile and a half when the least bit cool. Once it makes the shift, all is well. The same for engaging reverse.

I have tried changing the fluid and even trying both Lucas' and Prolong's miracles in a bottle. No joy.

Now, I have never worked on an automatic transmission. Pulled apart and rebuilt Vickers Fluid Power transmissions, never an automotive automatic though.

As I read the service manual and look over the parts manual, I think I am up to some of the diagnostic work and remediation. If I read right, the likely candidates are sticking valves and/or o-rings in the modulators. Perhaps (but I doubt) a sticking governor but that can be plan B.

Any suggestions? Have any of you attempted working on a Power-shift?

[Warren Webb]

I'm far from being an automatic trans expert but from what your saying the first thing that comes to mind is a band adjustment. It's been a while since I did it but real easy. One thing I do remember is it called for a "special tool" which was basically a spacer, either 1/4" or 3/8ths. I just used a ratchet extension instead.

[spokejr]

That's one of the questions I have have forgot, what is the thickness of that spacer? Also, for the rear band the manual states that you turn the screw clockwise until it "overruns" and then loosen by 1 1/2 turns. What do they mean by "overruns", that the screw starts to resist?

[bezhawk]

The service tool has a pre-set torque value, and it slips above that torque. Basically it's 15 in lbs. on a 1/4" spacer between the servo pawl and the band.

[karterfred88]

Since it shifts OK after warming up, I suspect governor valve or shift valve in valve body varnished or "gooped up" (yeah I know not a recognized technical term). If you pull the pan again, try shoving some cleaner through the valve body and governor valve. Adjustments may work, but, it may be time to R&I some parts and clean out old debris. If you get lucky you may not need to tear it down any further, just cleaning out the parts and tubes you can get to while it's still in the car. Changing the fluid multiple times may also work, but you may never get enough of it out to dislodge the offending debris, and that can get expensive.

[spokejr]

The service tool has a pre-set torque value, and it slips above that torque. Basically it's 15 in lbs. on a 1/4" spacer between the servo pawl and the band.

Now I understand what they were saying.

[StudeRich]

The slowness of Reverse engagement is likely because the Rear Servo Seals are hard as a rock and this usually means a Trans. Re-build, as the Seals in the Clutch Drums will be in similar condition.

All of the suggestions here of course are assuming that you have set the Throttle Pressure correctly, that is key to all shifting issues.

Most of these Borg Warner Transmissions in our Cars are just NOW old enough to be due for a rebuild, a situation almost unheard of in most Automatic Transmissions that have been rebuilt at least once or twice in that many years.

[bezhawk]

If it holds well once engaged, then servo seals, and valve body are very easily serviced without disassembly of the transmission. Just drop the pan, and three bolts hold on the valve body. one of the simplest auto transmission ever made.

[Dan Timberlake]

How does the new fluid look?

Which Lucas product did you use? A quick scan suggests none make the claim of freeing up varnished valve bodies.

I'd probably "invest" in a treatment of Seafoam trans-tune followed eventually within another change. I've had some pretty positive results in the past.
I believe TransTune is thinner viscosity than Lucas Trans Fix, like solvent, and even makes specific claims for de-gunking valve bodies etc.

http://seafoamsales.com/trans-tune/

I see some Lucas testimonials DO report improvements in cold weather performance

[GrumpyOne]

The only additive that I've had good luck with is Lubegard. It's not readily available in your FLAPS as it is a product mostly used by the tranny pros.

I was turned on to the product by an old high school classmate who operated a transmission repair shop until he retired a few years ago. It's terrific and they have a flush/install kit and my preference is for Redline Type F synthetic fluid...

[nels]

I had exactly the same problem with a 55 TBird years ago. A friend of mine advised me to pour a pint of lacquer thinner in the trans and drive it for an hour or so. The heat from driving would elevate the trans temp above the boiling point of the thinner and it would boil it out of the system. It actually worked very well. I noticed an improvement after the first time so I gave it another treatment a week later. Honestly, the trans acted as if it was new. I assume it cleaned all the varnish out of the valve body and softened all the seals.
I'm sure this method will have plenty of criticism but it worked for me. I think all these tune up lubricants that you see out there work on the same principle but they are dialed way back from what I did.

[T.J lavallee]

Adding lacquer thinner to an automatic transmission is something I've never heard of. The concept as to how it works seems to make sense as you explained it. Did you drain the tranny and washed the filter after the first application or just leave it in and repeat the procedure a second time then drain the system? My transmission works just fine but I suppose I'd try it as a last resort before I'd have the tranny rebuilt if that was my only alternative. Anyone else out there ever tried this procedure?

[jpepper]

The Borg Warner transmissions suffer from the same problems old AMC and Ford transmissions have. Seals get old, hard and leak. I am referring to the seals in the servos and clutch pack pistons. Fluid passes the seal generating heat. enough heat softens the seal then everything works. I had a Ford pickup with a C-6. It would not engage any forward gears when cold. I would start it, drop it in drive, then wait for several minutes for the forward clutch to pull in. After the first time it worked fine. I pulled the trans eventually and rebuilt it. Your Powershift needs the same thing. It is time for a full rebuild. It may work like it is for some time but eventually it will fail and it never happens at a convenient time or place. If you waight for failure it may cost you much more.

[nels]

Adding lacquer thinner to an automatic transmission is something I've never heard of. The concept as to how it works seems to make sense as you explained it. Did you drain the tranny and washed the filter after the first application or just leave it in and repeat the procedure a second time then drain the system? My transmission works just fine but I suppose I'd try it as a last resort before I'd have the tranny rebuilt if that was my only alternative. Anyone else out there ever tried this procedure?

It's been a long time ago so I don't remember but I seriously doubt if I changed the filter and fluid after the fix but I'm sure that would be a good move. It was a last resort when I tried it but if I had the same problem again I would try it again but as a last resort.

[dynolou2]

The lacquer thinner may work for a while, but too much will turn the o rings and seals to jello. I grabbed a jar of trans repair at a used car lot once, when I opened it it smelled of lacquer thinner - not buying any car there. Lou Cote