Flex plate/converter problem

[73K20]

Ok so I picked up a 77 GMC with a sb400 and a swapped in th350/205. The guy used a flex plate off a 350 so it cracked and vibrated. I purchased the correct the plate and installed it this weekend. Here's the issue I ran into.

The torque converter mated up fine with old flex plate but when I got everything back together I had about a 1/4" gap between the plate and converter.

So to get it running atleast i checked and double checked the converter was seated and used washers as spacers, that leads to the Next problem.

It runs great no more vibration however when I start it I get an awful high pitch noise, starter needs shimmed I think? Which way?

And the last and worst problem. When put into gear she doesn't move at all. Then when I put her back in park it makes a really weird noise. Almost like metal clanging together. Anyone have any ideas?

I know it's long, I appreciate any help


1993 F250 3k in the 460-my 1st truck
1973 K20 6" lift-bright future
1967 F250 2x4-diesel swap in its future

 

[350runner]

How did you go about replacing the flywheel? Drop the trans?

Sent from the dust in front of you!

 

[scottybaccus]

probably installed it backwards

 

[chengny]

This new "th350/205" combo - is it known to be good?

I have to wonder - because of this:

"And the last and worst problem. When put into gear she doesn't move at all. Then when I put her back in park it makes a really weird noise. Almost like metal clanging together. Anyone have any ideas?"

The 1/4" gap (between the flexplate and the T/C) that you observed before inserting the shims is a bit more than normal - normal is considered to be 1/16" to 1/8". I would remove enough washers to create a gap of 1/8".


As far as the no-go issue (and metallic noises when shifting into park) - this is a stretch but, you might try checking your shifter linkage adjustment.

Adjust:

Apply the parking brake.
Loosen the screw (242) or the nut (236), as used:

You must be registered for see images attach

Put the column selector lever in the "N" (Neutral) position. This means to put the lever into the neutral gate. Do not use the indicator to find the neutral position.

Put the transmission in neutral at the local shift lever ("A"):

You must be registered for see images attach

Move the shift lever (A) to the forward position. Then move it back to the second detent (this means 2 clicks back from the most forward/CCW position).

Hold the rod (240) tightly in the swivel (232).

Tighten:

Nut (236) or the screw (242) to 23 N'm (17 ft. lb.).

Put the column selector lever In the "P" (Park) position.

Check the adjustment

The column selector lever must go into all positions.

The engine must start in the "P" (Park) or "N" (Neutral) positions only. Adjust If needed.

CAUTION: With the selector lever In the "Park" position, the parking pawl should freely engage within the rear (reaction) internal gear lugs or output ring gear lugs and prevent the vehicle from rolling, which could cause personal injury.

Align the indicator. If needed.

Release the parking brake.

 

[MadOgre]

Sorry to be the bearer of bad news But pull your transmission as it is now trashed. You have mashed the pump with the torque converter. The converter was not mated properly to the pump. what you hear is the converter rubbing on the pump but it is not ever going to engage because the tabs are ground off now. That's why you get a no go with the gears.

Better off just getting another transmission as that one is now full of metal filings.

Sorry bud!

 

[chengny]

Yeah MO - that's what I would think too, except for the fact that he says this:

i checked and double checked the converter was seated

He seems to be aware of how critical it is to get the tabs fully coupled into the pump.

And he initially had a 1/4" gap between the TC and the flex (with the bellhousing made up to the engine block - I assume).

Usually the pump gets crushed by trying to bolt the transmission up to the engine with the T/C not fully seated - and the T/C not being fully seated is usually evidenced by the lack of a gap between it and the flexplate.

IDK.

 

[MadOgre]

Ya Idk either. Its classic mashed pump though.

 

[73K20]

Hey all i appreciate the help,
Ok so the fix was actually pretty funny. Tcase shifter got bumped into neutral she moves just fine now and the noise going into park is gone. I was just so tired and still had a 2 hour drive home I wasnt thinking straight.

To swap the plate I used guide bolts and just pulled the trans back, im pretty sure it's not in backwards there's only one way it has a flat surface to mate up with the torque converter.
I still can't fig out where that big of a gap came from but I left probably just about an 8th inch maybe alittle less but I knew there should a tiny bit of a gap but not 1/4 inch or more.


1993 F250 460 waiting for diesel swap-my 1st truck
1973 K20 6" lift-totaled
1967 F250 2x4-building a 460 to drop in
1977 K10 lifted, mildly built sb400

 

[73K20]

This new "th350/205" combo - is it known to be good?

I have to wonder - because of this:

"And the last and worst problem. When put into gear she doesn't move at all. Then when I put her back in park it makes a really weird noise. Almost like metal clanging together. Anyone have any ideas?"

The 1/4" gap (between the flexplate and the T/C) that you observed before inserting the shims is a bit more than normal - normal is considered to be 1/16" to 1/8". I would remove enough washers to create a gap of 1/8".


As far as the no-go issue (and metallic noises when shifting into park) - this is a stretch but, you might try checking your shifter linkage adjustment.

Adjust:

Apply the parking brake.
Loosen the screw (242) or the nut (236), as used:

You must be registered for see images attach

Put the column selector lever in the "N" (Neutral) position. This means to put the lever into the neutral gate. Do not use the indicator to find the neutral position.

Put the transmission in neutral at the local shift lever ("A"):

You must be registered for see images attach

Move the shift lever (A) to the forward position. Then move it back to the second detent (this means 2 clicks back from the most forward/CCW position).

Hold the rod (240) tightly in the swivel (232).

Tighten:

Nut (236) or the screw (242) to 23 N'm (17 ft. lb.).

Put the column selector lever In the "P" (Park) position.

Check the adjustment

The column selector lever must go into all positions.

The engine must start in the "P" (Park) or "N" (Neutral) positions only. Adjust If needed.

CAUTION: With the selector lever In the "Park" position, the parking pawl should freely engage within the rear (reaction) internal gear lugs or output ring gear lugs and prevent the vehicle from rolling, which could cause personal injury.

Align the indicator. If needed.

Release the parking brake.

That's some really good stuff to know, ive never adjusted the linkage on these. Thanks for posting that up


1993 F250 460 waiting for diesel swap-my 1st truck
1973 K20 6" lift-totaled
1967 F250 2x4-building a 460 to drop in
1977 K10 lifted, mildly built sb400

 

[350runner]

It's always the small stuff lol. Glad you didn't have to spend hundreds to figure it out.

Sent from the dust in front of you!

 

[bucket]

I've had gaps around a 1/4 inch before, never thought much about it, but I'm not a tranny builder. I've always just slid the converter back forward and bolted it up.

 

[73K20]

It's always the small stuff lol. Glad you didn't have to spend hundreds to figure it out.

Sent from the dust in front of you!

Ya I'm pretty glad that's all It was. That noise had me worried for a min.


1993 F250 460 waiting for diesel swap-my 1st truck
1973 K20 6" lift-totaled
1967 F250 2x4-building a 460 to drop in
1977 K10 lifted, mildly built sb400

 

[73K20]

I've had gaps around a 1/4 inch before, never thought much about it, but I'm not a tranny builder. I've always just slid the converter back forward and bolted it up.

Interesting


1993 F250 460 waiting for diesel swap-my 1st truck
1973 K20 6" lift-totaled
1967 F250 2x4-building a 460 to drop in
1977 K10 lifted, mildly built sb400

 

[MadOgre]

The Flex plate flexes. In and Out. So there is supposed to be a small amount of movement available for the torque converter to move in and out.

It was the sound and no go in gear that had me set on a mashed pump

 

[350runner]

You must be registered for see images

You must be registered for see images

Sent from the dust in front of you!