trans troubles - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**jocko** · 10-23-2012, 04:04 PM

Off the top of your head - any idears why a TH400 would not stay in Park when shifted there? I don't have a lot of detail unfortunately - the shipper that was bringing the truck I bought down from WA called and said that the seller crawled under the truck, jiggled some stuff and then he could drive it onto/off of the trailer. But when he got to an intermediate stop, he had to back it off the trailer to load another customer's vehicle, and when he re-loaded mine - it won't stay in park again. And, of course, it's "against their policy" to get under the truck. That's friggin awesome - so they LEFT the truck in WA a few miles from the owner's house. Wasnt' that nice of him?

Besides the mess of what it took to arrange to be home on the day it was to arrive, now it will be late a week+ BEST case. And, I now know I have a truck coming that was advertised as having a slight trans leak, but it runs great no problema - that I'm gonna have to rebuild right off the bat because I won't be able to trust that I can get it to stay in Park when I drive it somewhere. That could be kinda dangerous at worst, extremely inconvenient at best. Sounds like it might be a linkage issue, but pretty pissed that the owner didn't disclose (he didn't even mention the trouble getting it loaded until I told him what the driver described...) and the shipper saw fit to leave on the side of the road somewhere. I didn't fall off the turnip truck yesterday, I always assume there will be "issues" with a truck this old, but not being able ot put it in Park is kind of a big deal when I was just expecting a little leak...

Anyway - apologize my rant, it'll all work out, but buying a vehicle from across the country is hassle enough, gets much worse quickly when you realize you've been slightly had. Rust not mentioned is one thing, but not being able to put in Park is another thing altogether. Still want the truck, but wouldn't have offered what I offered had I known. Always a risk, but I'm getting tired of the short end of the stick with flaky buyers (the 66 I just sold) and sellers (the 71). Hmm.

So.... interested if any thoughts from you trans gurus off the top of your head as reasons why it would roll in Park, which is all I can assume is happening based on what the somewhat less than clear driver is describing to me.

Thanks gents!

GMCJOE · 10-23-2012, 04:26 PM

The spring that's on the linkage to keep it in place a long the frame rail and body could have an issue. Most likely it's linkage related, not transmission. Might just be the nut loose where the linkage slides in on the transmission, not allowing it to shift back in to park. Doesn't sound like anything major, just inconvenience since you was getting it shipped. I hate seller's that don't disclose everything.

SS Tim · 10-23-2012, 04:54 PM

Trying to picture the problem and the most likely I am coming up with is the trans. linkage is binding due to a mount issue. When the truck (if I understand correctly) is at an angle it is binding on the exhaust. Should be an easy enough fix and I don't see this as an "overhaul required" repair. If it engages the parking pawl when level the trans. should be OK. It could just be the linkage bushings are shot and not pulling it far enough to engage "park" on an angle or holding a torque load.Remember the shift linkage internal has a comb that the has a spring loaded engagement. If it is not being push/pulled far enough to get it "over the hump" the parking pawl will not engage. Now if the pawl is broken that would be an internal issue. But it seems to make more sense that the bushings are shot and the mounts are allowing movement preventing that last little engagement.

SS Tim · 10-23-2012, 05:18 PM

A couple of drawings

**jocko** · 10-23-2012, 07:14 PM

thanks for the posts guys - update from the seller - all fwd gears inop. So, shipper had it a little backwards... but it's internal, confirmed by the trans shop he had it towed to. Kinda has to get it fixed so the shipper will even load it. So, despite the lousy 1 week delay, and preipheral pitas, seller back in good graces as he's gonna get it fixed it sounds like.

whew, for now.

Oh - and the shipper left it in a co-shipper's locked yard, so initial case of chinese telephones on the report i received is not as bad as originally passed.

GMCJOE · 10-23-2012, 07:42 PM

Sounds good for you... brand new rebuilt trans on the sellers dime. One thing less to worry about for you. Best of luck!

**jocko** · 10-23-2012, 07:55 PM

thanks - but it won't be rebuilt, trans shop is only gonna fix whatever is wrong - the rest will still be as old as it was, and that's fine, I don't need him to repair stuff that's just worn and old - just what's broken. But, maybe it will fix some of the leaks for free in the process.

10-23-2012, 04:04 PM	#1
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,960	trans troubles Off the top of your head - any idears why a TH400 would not stay in Park when shifted there? I don't have a lot of detail unfortunately - the shipper that was bringing the truck I bought down from WA called and said that the seller crawled under the truck, jiggled some stuff and then he could drive it onto/off of the trailer. But when he got to an intermediate stop, he had to back it off the trailer to load another customer's vehicle, and when he re-loaded mine - it won't stay in park again. And, of course, it's "against their policy" to get under the truck. That's friggin awesome - so they LEFT the truck in WA a few miles from the owner's house. Wasnt' that nice of him? Besides the mess of what it took to arrange to be home on the day it was to arrive, now it will be late a week+ BEST case. And, I now know I have a truck coming that was advertised as having a slight trans leak, but it runs great no problema - that I'm gonna have to rebuild right off the bat because I won't be able to trust that I can get it to stay in Park when I drive it somewhere. That could be kinda dangerous at worst, extremely inconvenient at best. Sounds like it might be a linkage issue, but pretty pissed that the owner didn't disclose (he didn't even mention the trouble getting it loaded until I told him what the driver described...) and the shipper saw fit to leave on the side of the road somewhere. I didn't fall off the turnip truck yesterday, I always assume there will be "issues" with a truck this old, but not being able ot put it in Park is kind of a big deal when I was just expecting a little leak... Anyway - apologize my rant, it'll all work out, but buying a vehicle from across the country is hassle enough, gets much worse quickly when you realize you've been slightly had. Rust not mentioned is one thing, but not being able to put in Park is another thing altogether. Still want the truck, but wouldn't have offered what I offered had I known. Always a risk, but I'm getting tired of the short end of the stick with flaky buyers (the 66 I just sold) and sellers (the 71). Hmm. So.... interested if any thoughts from you trans gurus off the top of your head as reasons why it would roll in Park, which is all I can assume is happening based on what the somewhat less than clear driver is describing to me. Thanks gents! Last edited by jocko; 10-23-2012 at 07:18 PM.

10-23-2012, 04:26 PM	#2
GMCJOE Registered User Join Date: Aug 2012 Location: Junction City, KS Posts: 782	Re: trans troubles The spring that's on the linkage to keep it in place a long the frame rail and body could have an issue. Most likely it's linkage related, not transmission. Might just be the nut loose where the linkage slides in on the transmission, not allowing it to shift back in to park. Doesn't sound like anything major, just inconvenience since you was getting it shipped. I hate seller's that don't disclose everything. __________________ Joseph Joe's 69 GMC http://67-72chevytrucks.com/vboard/s...d.php?t=543253 1969 GMC SWB-350 SBC 700R4 2013 Ram 2500 CC Laramie Longhorn Edition-6.7 PPEI EFI Live CSP5 5” ProFlo Exhaust

10-23-2012, 04:54 PM	#3
SS Tim Registered User Join Date: Aug 2010 Location: Edwards, CA Posts: 7,503	Re: trans troubles Trying to picture the problem and the most likely I am coming up with is the trans. linkage is binding due to a mount issue. When the truck (if I understand correctly) is at an angle it is binding on the exhaust. Should be an easy enough fix and I don't see this as an "overhaul required" repair. If it engages the parking pawl when level the trans. should be OK. It could just be the linkage bushings are shot and not pulling it far enough to engage "park" on an angle or holding a torque load.Remember the shift linkage internal has a comb that the has a spring loaded engagement. If it is not being push/pulled far enough to get it "over the hump" the parking pawl will not engage. Now if the pawl is broken that would be an internal issue. But it seems to make more sense that the bushings are shot and the mounts are allowing movement preventing that last little engagement. __________________ Thanks, Tim * VIN/Model Decoders * Power Team Charts (engine/transmission/gear ratio) * Post Your Pickup SPID Blazer SPID Suburban/Panel SPID * RTFM ... Read The Factory Manuals... download 'em here Highlanders Do you have a 1972 Plaid Pickup? Plaid Blazer ** Plaid Suburban

10-23-2012, 05:18 PM	#4
SS Tim Registered User Join Date: Aug 2010 Location: Edwards, CA Posts: 7,503	Re: trans troubles A couple of drawings Attached Images __________________ Thanks, Tim * VIN/Model Decoders * Power Team Charts (engine/transmission/gear ratio) * Post Your Pickup SPID Blazer SPID Suburban/Panel SPID * RTFM ... Read The Factory Manuals... download 'em here Highlanders Do you have a 1972 Plaid Pickup? Plaid Blazer ** Plaid Suburban

10-23-2012, 07:14 PM	#5
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,960	Re: trans troubles thanks for the posts guys - update from the seller - all fwd gears inop. So, shipper had it a little backwards... but it's internal, confirmed by the trans shop he had it towed to. Kinda has to get it fixed so the shipper will even load it. So, despite the lousy 1 week delay, and preipheral pitas, seller back in good graces as he's gonna get it fixed it sounds like. whew, for now. Oh - and the shipper left it in a co-shipper's locked yard, so initial case of chinese telephones on the report i received is not as bad as originally passed.

10-23-2012, 07:42 PM	#6
GMCJOE Registered User Join Date: Aug 2012 Location: Junction City, KS Posts: 782	Re: trans troubles Sounds good for you... brand new rebuilt trans on the sellers dime. One thing less to worry about for you. Best of luck! __________________ Joseph Joe's 69 GMC http://67-72chevytrucks.com/vboard/s...d.php?t=543253 1969 GMC SWB-350 SBC 700R4 2013 Ram 2500 CC Laramie Longhorn Edition-6.7 PPEI EFI Live CSP5 5” ProFlo Exhaust

10-23-2012, 07:55 PM	#7
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,960	Re: trans troubles thanks - but it won't be rebuilt, trans shop is only gonna fix whatever is wrong - the rest will still be as old as it was, and that's fine, I don't need him to repair stuff that's just worn and old - just what's broken. But, maybe it will fix some of the leaks for free in the process.



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