HELP 2 minutes to 12o' clock - Disaster averted - Advice/Help needed

CopperNick

Royal Smart Person
Supporting Member
Feb 20, 2018
2,223
113
Canada
Ouch. That's not polite. Just me wondering aloud at this point but one of things that I remember from my courses so many years ago was that the torque converter had a specific set of steps that had to occur in order to ensure that it got installed correctly. The splining on the input shaft had to be checked for burrs and nicks. The converter needed to be filled with about a quart of ATV so that its vanes and guts wouldn't be dry during the initial startup. The most critical thing mentioned was that the converter had to seat correctly and completely. Even before mating the transmission to the block, both the hole in the crank and the diameter of the converter snout had to be miked to make sure the one would accept the other. Both snout and hole had to be clean and free of burrs and nicks The snout had to be a smaller diameter than the hole to slide in freely, otherwise it would just jam up against the pocket in the crankshaft flange and cause the crank to be pushed towards the front of the block. Starting to sound familiar here?

The other very critical event that had to occur was that, when the converter was slipped over the front pump input shaft, it had to be turned or spun very slowly with very gentle pressure applied to it until a solid and distinctive clunks was felt/heard. This had to happen three times in succession in order for the converter to line up and index correctly with the shaft and pump. The sure sign of success was if the converter, once put in position, sat deeper or below the perimeter mounting surface of the transmission bell housing by around 3/8th's of an inch.

If the converter had not been completely and correctly seated, then the snout would sit proud of the case flange and, like noted above, even if it did index into the crank pocket, it would still try to push the crank ahead.

The absolute best sign that the converter got set into position correctly was that, once the case bolts that secured the transmission housing to the block were screwed in snugly, when you slipped back under the vehicle to attach the converter to the ring gear, you would find a space between the two and you would have to gently tease the converter forward to get it to align and the mounting blocks to index with the holes in the ring gear. Slipping the converter forward that 3/8ths of an inch does not adversely impact on the alignment of the converter to the pump, the design comes with the slack built into it by the engineers for just that purpose.

Given the choice of options here, I think it may be number two, the converter did not get seated completely. Had it been number one, just trying to align the box on the pins in the block would have difficult to impossible. Even if the installer had managed to get it all to line up, running the bolts down would not have brought the flange on the t-box bell housing up tight against the block; more likely the bolts would have gone tight and any attempt to force them would have snapped the ears off the case flange, or pulled the threads out of the block.


So. Being a TH400, it is worth rebuilding, speaking only for myself.



Nick
 

FluoFerret

Greasemonkey
Thread starter
Apr 2, 2018
184
43
Luxembourg
Given the choice of options here, I think it may be number two, the converter did not get seated completely. Had it been number one, just trying to align the box on the pins in the block would have difficult to impossible. Even if the installer had managed to get it all to line up, running the bolts down would not have brought the flange on the t-box bell housing up tight against the block; more likely the bolts would have gone tight and any attempt to force them would have snapped the ears off the case flange, or pulled the threads out of the block.


So. Being a TH400, it is worth rebuilding, speaking only for myself.



Nick

Hello Nicke

Thank you for your advice and sharing your thoughts. I think you might be right. I just started diassembling the transmission. The drive gear engaging the torque converter has the same damage than the converter (obviously).
Another issue might have been B&M messing up big time when building the transmission back in 2009: the offset notches on the gear for the torque converter were facing to the front of the transmission. According to the pump rebuild instructions it should have been the other way around. Unfortunately I didn't take a picture of it, but that's just unprofessionnal to install an important gear the wrond way in the pump housing...

Good news though:I didn't find any further damage inside the pump. I will replace the two gears though and look deeper. I need to know if these m,etal shavings come from inside the converter or from somewhere inside the transmission... If you like, I will keep you tagged in any future reply of mine :)

Here's the pictures of the transmission-pump. I think I was really lucky here that the pump housing is still intact. The gears will have to go though...

20220914_164116.jpg
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CopperNick

Royal Smart Person
Supporting Member
Feb 20, 2018
2,223
113
Canada
Not trying to spend money you don't have here but, even though the pump body appears intact and unharmed, I would personally still be very reluctant to try and just rebuild it and re-use it. This just might be one of those cases where doing a total swap out and installing a whole new complete pump could be the safest course of action. The pictures don't show any overt or physically visible signs of injury but the pump body casting could still have taken a hit, just not eyeball sized.

One other thought on your rebuild. Most builders who specialize in T-boxes have a vertically oriented jig or vise that supports the case on end. In this position it is easier to drop the various sub-assemblies into position and correctly set the circlips and retaining rings. It also offers tailshaft clearance so that the mainshaft drops in and can hang in position without getting knocked around like can happen with the case sitting flat on the bench.




Nick
 
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FluoFerret

Greasemonkey
Thread starter
Apr 2, 2018
184
43
Luxembourg
Not trying to spend money you don't have here but, even though the pump body appears intact and unharmed, I would personally still be very reluctant to try and just rebuild it and re-use it. This just might be one of those cases where doing a total swap out and installing a whole new complete pump could be the safest course of action. The pictures don't show any overt or physically visible signs of injury but the pump body casting could still have taken a hit, just not eyeball sized.

One other thought on your rebuild. Most builders who specialize in T-boxes have a vertically oriented jig or vise that supports the case on end. In this position it is easier to drop the various sub-assemblies into position and correctly set the circlips and retaining rings. It also offers tailshaft clearance so that the mainshaft drops in and can hang in position without getting knocked around like can happen with the case sitting flat on the bench.

I will check the surfaces with a straight-edge. Years ago I was clever enough to by a set made by Mitutoyo, as well as micrometers :LOL: Not cheap, but the best and reliable. if the surfaces are perfect after checking against the light, i will check for cracks with dye penetrant. I do that for most of my builds when eyeballing is not cutting it.

i will probably follow your lead on the jig/vise for the transmission. most rebuild documentations don't require it, many don't even mention it. maybe for them its just a prerequisite to do it right ^^ maybe i will build myself one with steel. i am quite proficient in welding ^^
 

57 Handyman

Greasemonkey
Feb 6, 2017
247
63
Ouch...yikes...ouch! Thats' a lifetime's worth of engine and transmission damage that none of us wants to experience and suffer! Unfortunately, there certainly is enough probable blame and responsibility to go around from your local repair shop to brand name re-builders/suppliers. Hopefully, your future efforts regarding classic car ownership are more pleasant and enjoyable.
 

ELCAM

G-Body Guru
Jun 19, 2021
703
93
What I see is a lot of heat, whether from improper assembly, poor lubrication or incorrect clearances would be hard to say with out having the transmission right in front of you.
 

Northernregal

Sloppy McRodbender
Supporting Member
Oct 24, 2017
3,297
113
Red Deer, Northern Montana territory
Uh oh, I doubt this material coloration is healthy in any way... Anybody got any experience or thoughts??

View attachment 207469 View attachment 207470
Top pic is rear thrust bearing and if it was jammed together that is gonna eat the load. It's replaceable so no worries. Bottom pic is rear planet and rear ring, shouldn't have been heated and is odd but your transmission guy will tell you what to do. I would personally reuse that and your pump, for a street car it'll be fine.

But I hate spending money to replace things that don't matter.
 
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FluoFerret

Greasemonkey
Thread starter
Apr 2, 2018
184
43
Luxembourg
Top pic is rear thrust bearing and if it was jammed together that is gonna eat the load. It's replaceable so no worries. Bottom pic is rear planet and rear ring, shouldn't have been heated and is odd but your transmission guy will tell you what to do. I would personally reuse that and your pump, for a street car it'll be fine.

But I hate spending money to replace things that don't matter.

I showed the rear planet/ring assembly to a local shop for transmissions, and they told me that it looks normal. They've never seen any rear assembly on an automatic transmission that was "pristine". not even on european cars where every little moving piece is rollerized with active lubrication.

this being said, they advised me to replace the rear thrustbearings with this kit from Sonnax: 34006-SPB. Apparently that's an upgrade that is worth every penny and improves longevity and performance.
 
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FluoFerret

Greasemonkey
Thread starter
Apr 2, 2018
184
43
Luxembourg
Small update on the engine/transmission tear-down:

a little scrap metal cut to fit, welded and a can of paint, and the engine-stand serves as a transmission-stand :)
20221002_164738.jpg
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What wasn't so fun, is what I discovered while further disassembling and inspecting the TH400 (build by B&M).
The rear bushing ate some metal, but thank god, the rear output shaft isn't damaged in any way. It seems that this got assembled in a dirty place with no respect for quality.
20221003_205259.jpg
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And to ice the cake, there was a seal ring missing inside the main assembly.
20221003_214401.jpg


I will post updates as soon as I received the parts for the rebuild... One thing is for sure, B&M will never get any money from me ever again...
 
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