Rebuilt Transmission Horror Story

[Bent Bolt]

Honestly, the only real way of filling a torque converter is by installing it in the vehicle and starting the engine.

To be really honest, I don't even soak the clutches when I build transmissions. Once the trans is installed and engine running for about 15 minutes, there is enough ATF splashing around to coat and soak every friction material inside. go for an easy road test for about 10 km then after that, go hard. If the trans doesn't work properly by then, most times there is something wrong.

As always, there are exceptions to the rule.

Your results may vary.

 

[toneybarber]

Update: I just got off the phone with the mechanic from the shop (the original shop) who has had my truck since Monday. He told me that he took it for a drive and heard/felt the problems again. He said he broke down the transmission and found that the "front drum" had some damage. He said that he was replacing it and that he would be finished with it late today.

What is the "front drum"?

When I dropped it off on Monday I very diplomatically suggested that he check the TC. He looked a little puzzled (not as if he didn't know what it was but rather as if it could be a possibility) and, interestingly, he did not claim to have checked it on the initial re-build. He did not say anything about the TC when I spoke to him today and not sure if I should press it. Would the TC normally be included in a "worst case scenario" rebuild?

 

[BrooklynBay]

The torque converter is replaced during an entire rebuild. Look at the pictures in the A4LD diary which show the torque converter, bell housing, front pump, and overdrive assembly. You will then know about the front drum. The first part contains the planetary gears (the updated version has more gears, and is tig welded), sun shell for the clutch pack plates, and a one way sprag.

 

[Glacier991]

Your typical A4LD rebuild does not replace the TC....Unless! the tranny was fragged or had extensive metal floating around, most shops will not replace the TC in a rebuild. In fact most shops replace as little as possible, and rarely if ever replace undamaged hard parts. This is a successful strategy in many trannies, but not in the A4LD.

I just bought a "rebuilt" A4LD I plan to tear down and inspect and then rebuild according to MY specs. It should be instructive.

By "front drum" I guess he means the OD Drum...

(This is for Bent Bolt: Ok ok, Coast Clutch drum)

 

[BrooklynBay]

It's a good idea to flush the cooler when installing a rebuilt transmission so that any left over fragments don't get pushed into the rebuilt unit.

 

[Glacier991]

<smacks Bent Bolt for telling he does not soak frictions>

The rest of you... SOAK them or at least get them wet with ATF during assembly.... I am cool with dipping them before you drop them in.... but get them wet. I go so far as to recommend that you start the vehicle after a rebuild.... run it thru the gears spending about 3o seconds in each then shutting it down for 30 mins or so... to double ensure all the friction material has absorbed all the ATF possible.

 

[BrooklynBay]

I usually saturate all of them with assembly lube (it looks like colored petroleum grease). I guess everybody has their own way of doing things. Why don't they come presoaked to condition the material?

 

[Glacier991]

Another excellent Q. I suppose given their cheap price per unit and the hassles of a soaked with hazardous material shipping issue.... maybe they just don't.

 

[BrooklynBay]

Other parts are shipped in a light coating of oil to prevent rust from building up from moisture.

 

[toneybarber]

Your typical A4LD rebuild does not replace the TC....Unless! the tranny was fragged or had extensive metal floating around, most shops will not replace the TC in a rebuild. In fact most shops replace as little as possible, and rarely if ever replace undamaged hard parts. This is a successful strategy in many trannies, but not in the A4LD.

I just bought a "rebuilt" A4LD I plan to tear down and inspect and then rebuild according to MY specs. It should be instructive.

By "front drum" I guess he means the OD Drum...

(This is for Bent Bolt: Ok ok, Coast Clutch drum)

Thanks, BrooklynBay for pointing me back to Glacier991,s A4LD Rebuild Diary. Are these images showing the "front drum"?

Glacier991, I have perused your A4LD rebuid diary many times and have found it to be insightfull and informative. If you are planning to chronicle this rebuild, I'll be watching for sure.

Are you suggesting that, although not a universal transmission rebuild approach, when rebuilding the A4LD one should almost certainly replace the torque converter? If so, why and would it be reasonable to ask that that be done?

 

[BrooklynBay]

A torque converter from a blown transmission could store a lot of fragments which could clog up a rebuilt transmission. If the parts on an old torque converter are old, and borderline from blowing apart, it will be another expensive rebuild on your transmission. Those fragments could get pushed into every passage way, and clog things up (including the cooler). It's not worth saving money by reusing the old one.

 

[Bent Bolt]

< Ow!!! That smarts, Glacier!!! >


Also A4LD converters have a nasty habit of wearing out the splines for the input shaft.

Never thought of why the frictions are not pre-soaked but I think it's just a matter of costs. The manufacturer doesn't have to shell out for ATF to soak the frictions.

 

[toneybarber]

Update: I have been very much under the weather and haven't felt too much like doing anything but clinging to life. However, I decided to take a drive today to test the transmission. I'm happy to say that the problem seems to have been corrected and, fortunately, I did get a one year warranty on the work. I'll keep my fingers crossed and do a little more extensive driving as soon as the darkly cloacked dude with the scythe leaves...

Thanks to all for your input. To the masters: my deepest gratitude.

Toney