TH400 Going Bye-bye - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**COBALT** · 10-10-2005, 12:59 PM

Guys:

I started hearing that tell-tale whistling-whirring sound usually heard when the torque converter is starting to fail. Since I'll probably need a new one, and the transmission has a lot of miles on it anyway I think I'll be looking for a rebuilt.

I won't have time to take it out of the truck, and I won't have time to work on it myself, so I'm going to have to wheel it into a shop and have them drop it out, rebuilt it with a new torque converter, and put it in the truck for me.

Anyone know of a good shop in the Seattle area? What about the puget sound area in general? It doesn't have to be just Seattle...

Thx.

70 net440 · 10-10-2005, 07:25 PM

Check that your filter hasn't fallen off. I've seen this happen, and it makes a strange noise.

stllookn · 10-10-2005, 08:33 PM

I don't know of any good ones in Seattle but try the "click and clack" website and enter your zip code. There was a guy at Monroe that specializes in trannmissions A-Z 425 397-6111. He is in Everett and his name is Bill Dettrich. He seemed nice and had a better price than I have been quoted in most shops. The best shop I have heard about in Seattle is Dukes on first avenue 206 241-5355. Many shops say they just send the trannys to Dukes to be rebuilt. Didn't you just rebuild that tranny a couple of years ago?

**COBALT** · 10-10-2005, 09:30 PM

No, I just replaced the seals, and put on a new pan with a new gasket. I remember inspecting the torque converter and it looked like it was ok. I've been meaning to either rebuilt it myself or have someone do it. Right now I have no time to work on the truck besides tune-ups and such, so I'll have to send it in.

Longhorn Man · 10-10-2005, 11:37 PM

Quote:

Originally Posted by COBALT

I started hearing that tell-tale whistling-whirring sound usually heard when the torque converter is starting to fail...

Does this sound seem the worst when loading it up...say, trying to creep slowly up a steep driveway without spinning the tires?
Is there a way to verify it as being the converter?
Is it obviouse that i am concerned about my tranny since it is making a similar noise?

cableguy0 · 10-11-2005, 12:04 AM

it sounds like it could be either the sprag or the convertor going out. not to hijack but andy im amazed that th350 is still working behind that big caddy motor. you need a th400 badly. but anyways even if the convertor is going bad when they do go bad they put metal through the trans trashing everything else. by the time a converter wears out the trans is worn equally as much and needs rebuilt as well

Longhorn Man · 10-11-2005, 12:26 AM

Well, this tranny has only been hooked to the 500 for about 1200 - 1500 miles, and to the 425 for less than 200 miles.

Plus, the converter is out of a TH400, so the age of the converter is a moot point as far as the tranny age is concenred.
I have yet to tow anything, haven't hauled more than 1200 pounds, and in all reality, I don't rag on it too much. Granted, i have gotten into the throttle a few times, but nothing REAL severe.

cableguy0 · 10-11-2005, 12:29 AM

believe me it only takes ONCE my sb was eating th350's left and right for a good while i broke the front sprag and the low reverse sprag a couple times. ripped low reverse sprag outta the case that was neat. that th350 needs more than the stock sprag to think about living behind that big caddy.

**COBALT** · 10-11-2005, 01:36 AM

The reason why I think it's the torque converter is that the sound is worse during warm-up when the RPMs are high and pressure in the transmission case is at it's lowest. It doesn't seem to be better or worse under load at all. It'll do it sitting still from a cold start.

I'm thinking both halves of the converter are rubbing together, which means the lock-up clutch in the center is warn out. Any debris dropped by the converter will contaminate the valve body of the transmission over time. It's seen a lot of miles even before I bought the truck in 2001. Then it was the best thing in the truck before I did all of the work to get it running. I've been suspecting it's due for a rebuild for a while now. I've been babying it for 30,000 miles, and it saw some serious miles before that, so I think it's seen it's limit.

grebus1 · 10-11-2005, 11:39 AM

I've heard good things about Village Transmission in Edmonds. I haven't had any work done there myself, but they're close to my home and that's probably where I'd start if I needed tranny work done.

www.villagetransmission.com

cableguy0 · 10-11-2005, 12:24 PM

th400's dont have a lock up clutch in the converter.you could be hearing the bearing between the two halves starting to go bad. theres numerous things in the transmission that could make that noise.

67sss · 10-12-2005, 12:39 AM

Skagit Transmissions on Lila Lane in Burlington. That's where everybody here in the valley takes their stuff. They've been in business for e-ons. Or my house, got a 400 shortshaft(I think) for $75, came out of a mid 80's Z-28.

**COBALT** · 10-13-2005, 01:55 AM

Quote:

Originally Posted by cableguy0

th400's dont have a lock up clutch in the converter.you could be hearing the bearing between the two halves starting to go bad. theres numerous things in the transmission that could make that noise.

Exactly. That's what I was thinking. Doesn't matter what gear I'm in (D, L1, L2 or R), which means the valve body, the reverse band, and the two clutch drums are probably not involved. It doesn't sound like the pump bushing going bad, but it very well could be the pump. That also leaves the torque converter. It's one of the two I think.

...and no I'm not in the market for another transmission. I have three to work with, but this is the one in the best shape. The others I have are for me to rebuild whenever I have time...whenever that is.

Thanks for the help. I'll go make some calls.

10-10-2005, 12:59 PM	#1
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	TH400 Going Bye-bye Guys: I started hearing that tell-tale whistling-whirring sound usually heard when the torque converter is starting to fail. Since I'll probably need a new one, and the transmission has a lot of miles on it anyway I think I'll be looking for a rebuilt. I won't have time to take it out of the truck, and I won't have time to work on it myself, so I'm going to have to wheel it into a shop and have them drop it out, rebuilt it with a new torque converter, and put it in the truck for me. Anyone know of a good shop in the Seattle area? What about the puget sound area in general? It doesn't have to be just Seattle... Thx. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

10-10-2005, 07:25 PM	#2
70 net440 Junior Member Join Date: Sep 2003 Location: yreka, ca Posts: 270	Check that your filter hasn't fallen off. I've seen this happen, and it makes a strange noise. __________________ 63 C10 70 Coronet R/T 67 C10 70 Dart Swinger 71 K10

10-10-2005, 08:33 PM	#3
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	I don't know of any good ones in Seattle but try the "click and clack" website and enter your zip code. There was a guy at Monroe that specializes in trannmissions A-Z 425 397-6111. He is in Everett and his name is Bill Dettrich. He seemed nice and had a better price than I have been quoted in most shops. The best shop I have heard about in Seattle is Dukes on first avenue 206 241-5355. Many shops say they just send the trannys to Dukes to be rebuilt. Didn't you just rebuild that tranny a couple of years ago? __________________ '68 C20 Longhorn 50th Anniversary 400/TH400 '68 C20 Longhorn 50th Anniversary 468/TH400w/buckets '72 C20 Halfhorn (Longhorn w/o cab and front clip) '69 Flxible Cruiser (look up ugly in the dictionary)

10-10-2005, 09:30 PM	#4
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	No, I just replaced the seals, and put on a new pan with a new gasket. I remember inspecting the torque converter and it looked like it was ok. I've been meaning to either rebuilt it myself or have someone do it. Right now I have no time to work on the truck besides tune-ups and such, so I'll have to send it in. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

10-11-2005, 12:04 AM	#6
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	it sounds like it could be either the sprag or the convertor going out. not to hijack but andy im amazed that th350 is still working behind that big caddy motor. you need a th400 badly. but anyways even if the convertor is going bad when they do go bad they put metal through the trans trashing everything else. by the time a converter wears out the trans is worn equally as much and needs rebuilt as well __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

10-11-2005, 12:26 AM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Well, this tranny has only been hooked to the 500 for about 1200 - 1500 miles, and to the 425 for less than 200 miles. Plus, the converter is out of a TH400, so the age of the converter is a moot point as far as the tranny age is concenred. I have yet to tow anything, haven't hauled more than 1200 pounds, and in all reality, I don't rag on it too much. Granted, i have gotten into the throttle a few times, but nothing REAL severe.

10-11-2005, 12:29 AM	#8
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	believe me it only takes ONCE my sb was eating th350's left and right for a good while i broke the front sprag and the low reverse sprag a couple times. ripped low reverse sprag outta the case that was neat. that th350 needs more than the stock sprag to think about living behind that big caddy. __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

10-11-2005, 01:36 AM	#9
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	The reason why I think it's the torque converter is that the sound is worse during warm-up when the RPMs are high and pressure in the transmission case is at it's lowest. It doesn't seem to be better or worse under load at all. It'll do it sitting still from a cold start. I'm thinking both halves of the converter are rubbing together, which means the lock-up clutch in the center is warn out. Any debris dropped by the converter will contaminate the valve body of the transmission over time. It's seen a lot of miles even before I bought the truck in 2001. Then it was the best thing in the truck before I did all of the work to get it running. I've been suspecting it's due for a rebuild for a while now. I've been babying it for 30,000 miles, and it saw some serious miles before that, so I think it's seen it's limit. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

10-11-2005, 11:39 AM	#10
grebus1 Registered User Join Date: Feb 2000 Location: Edmonds, WA Posts: 322	I've heard good things about Village Transmission in Edmonds. I haven't had any work done there myself, but they're close to my home and that's probably where I'd start if I needed tranny work done. www.villagetransmission.com __________________ '72 Chevy Suburban Custom Deluxe 10, 402/TH400

10-11-2005, 12:24 PM	#11
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	th400's dont have a lock up clutch in the converter.you could be hearing the bearing between the two halves starting to go bad. theres numerous things in the transmission that could make that noise. __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

10-12-2005, 12:39 AM	#12
67sss Registered User Join Date: Nov 2002 Location: Mt. Vernon, WA.. Posts: 2,326	Skagit Transmissions on Lila Lane in Burlington. That's where everybody here in the valley takes their stuff. They've been in business for e-ons. Or my house, got a 400 shortshaft(I think) for $75, came out of a mid 80's Z-28.



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