Transmission slow in morning

k20_chevy · 04-07-2009, 08:22 AM

I searched and only found the opposite problem I'm having with my th400 trans. when I start it up in the morning the trans will wine the whole time and when put into any gear be it reverse or drive it slowly engages. Then when I go to drive down the road it doesn't want to shift.

But after it warms up from a trip to the store it goes in gear like normal and shifts normal.

This issue only started a few months back after the trans. line blew off the radiator and lost I would say over 3/4 of the fluid. I refilled it of course and finished driving it home. I don't know much about transmissions yet. From other posts I have read, could it be my torque converter or the bands in my trans. got messed up when the line came off.

hotrodpc · 04-07-2009, 09:12 AM

Are you sure the trans fluid has been brought back to where it is supposed to be? Not likely the converter failed. Anything else could have been damaged though, if you continued to drive it and tried. Anytime you get in that situation and its slipping. Just stop it. Don't try to make it that extra 3 feet slipping the transmission the whole way. That is the easiest way to heat up and wear out clutches and burn steels. Nornally when you have the oposite problem, where it works while cool then warms up and strats to slip, is worn clutches and seals. While the fluid is thicker and cold, the trans seems to work, but the minute the fluid gets warmed and thinner the trans fluid gets around the worn seals, and/or the clutch packs are worn to the point the piston can not travel far enough to compress the clutches and steels to the pressure plate and clamp down to activate that paticular clutch drum. In your case where it is the opposite. It is usually hardened or burnt seals and/or worn clutch packs. The seal is hard, will not flex and the fluid is able to get around the seal not being able to compress the piston... yada yada. As it warms up, the seals become a little bit flexible from being warmed and start to work. In either situation, the trans is short lived. In your case, you can try a trans additive and it may prolong the life a bit longer by conditioning the seals. If the clutch packs are worn to far, there is nothing that can fix that other than a rebuild. Sounds like you may have a short lived trans. Also the line coming off would have only added to the already worn trans. So the line coming off is not what killed the trans as far as damage, but sounds as if it were a weak trans already if it could not handle that, and just the straw that broke the camels back. Do check your fluid level though and be sure you have it correct. That may just fix your problem if you did not refill it enough. Sometimes if its a bit low, as it warms up it expands to act like you have more fluid, so be sure the level is correct.

k20_chevy · 04-07-2009, 09:55 AM

Thanks for the quick reply. I did recheck the fluid and always check it almost on a weekly basis. Sounds like I will be replacing the trans at some point. It is my mud truck so not too big a deal.

I probably drove it 500 feet after the line come off to get out of the huge intersection. Sounds like my torque converter is fine but my trans is on its last leg.

I must be lucky or the th400 trans is really hard to beat like most claim. I've been running the truck with this issue for coming close to a year.

With that, could I replace it with a 700r4 trans instead?

Oh, and my truck is a 1981 Chevy k20 3/4 ton 4x4 with a 350 engine and th400 trans.

hotrodpc · 04-07-2009, 10:15 AM

If it has lasted a year this way, try to add a trans additive that will soften them seals. You just might revive it a bit. The T400 is hard to tear up. Sure it can be done. Is that the original trans in the truck? If so, it doesn't have the good sprag. If you are using it as a mud truck, you want it to be tough, try to find the good sprag drum. If its your mud truck, are you really concerned about the OD??? For what little fuel you will save with the OD, and the added expense of buying a 700r4 and more expensive to build, I'd certainly stay with the bullet proof 400. 700r4 is a weak transmission. It can be modified to have some strength in some areas, but like a chain, if you do not strenfthen all the weak parts, its only as strong as the weakest link. Even if you do get a good 700r4 and you don't break it, it will not last as long as 400. You can get close to 200,000 out of a 400 with some abuse along the way. With some abuse, I'd say you'd be doing good to get 100,000 out of a 700r4. I am in process of building my T400 for my 86 3/4 ton. I wish it were 4x4. I have acquired the good sprag drum and got the 34 element sprag in the mail yesterday. Now I need to order the rest of the kit and I get to start putting it back together. I am doing some trick stuff to it, and it will be bullet proof and able to handle all the abuse I can give it. There are many parts from the 4L80-E that you can add and use on the 400. Like an extra clutch in the clutch packs using the 4l80-E drum pistons, and pressure plates. Also a better designed snap ring from the 4L80-E can be used on the 400 too. Those little things add up.

k20_chevy · 04-07-2009, 11:16 AM

OK. I will get some lucas trans. additive this weekend.

I not familiar with the internals of the transmission yet. What is a "good sprag?"

leolkfrm · 04-07-2009, 11:25 AM

Hmmmmmmm, shot of geritol at night gets rid of sluggishness in the am,....

sorry just had to!

So is there any discoloring of the fluid or burnt smell?

hotrodpc · 04-07-2009, 11:41 AM

The good sprag is the 34 element sprag that has to run on a smooth race drum. With the smooth race drum you can use the 16 elelement or the 34 element. With the later drums, they are notched to use the 8 roller weak sprag, so you need smooth for either of the dog bone wedge sprags and the 8 roller drum is notched, so it worked similar to a ratchet. Here is a pic of the differences. Also I have a thread running with pics of the Turbo I tore apart of my T400 out of my 86 the way I bought it. It happened to of had a roller sprag failure. I bought a donor trans from a 69 Chevelle that had the good drum with a 16 element sprag, and I just got my 34 element sprag for that drum in the mail yesterday. The set up will be going into the 86 T400 and into the truck. When and if you ever get that thing rebuilt I can get you some info of the good stuff and what you may want to do to it or have done to it. Just don't let someone take your head off to do it. Many places will charge over $1200 for a tranny like I am building. I am probably going to get it done for about $300 that way its looking, maybe $350. So with labor, let a guy make a little money, and do you a good job, you should be able to get it done for $650.

Turbo 400 Disassembly

bradrhale · 04-07-2009, 11:44 AM

might want to explain what the sprags are and what they do so that he can understand exactly what to look for. i really cant explain it as i am not a tranny guy.

hotrodpc · 04-07-2009, 11:54 AM

Good idea, I may do that. For now I gotta run. I just got an email with 7 services to do, so now its time for me to go to work and make some people mad and earn some money. Must be why I like the forum so much. I do not make friends in my line of work.

k20_chevy · 04-07-2009, 12:04 PM

Quote:

Originally Posted by leolkfrm

Hmmmmmmm, shot of geritol at night gets rid of sluggishness in the am,....

sorry just had to!

So is there any discoloring of the fluid or burnt smell?

Nope. The fluid is red as can be.

04-07-2009, 08:22 AM	#1
k20_chevy Senior Member Join Date: Apr 2009 Location: Lorain Posts: 82	Transmission slow in morning I searched and only found the opposite problem I'm having with my th400 trans. when I start it up in the morning the trans will wine the whole time and when put into any gear be it reverse or drive it slowly engages. Then when I go to drive down the road it doesn't want to shift. But after it warms up from a trip to the store it goes in gear like normal and shifts normal. This issue only started a few months back after the trans. line blew off the radiator and lost I would say over 3/4 of the fluid. I refilled it of course and finished driving it home. I don't know much about transmissions yet. From other posts I have read, could it be my torque converter or the bands in my trans. got messed up when the line came off.

04-07-2009, 11:25 AM	#6
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	Hmmmmmmm, shot of geritol at night gets rid of sluggishness in the am,.... sorry just had to! So is there any discoloring of the fluid or burnt smell? __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

04-07-2009, 11:41 AM	#7
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,149	The good sprag is the 34 element sprag that has to run on a smooth race drum. With the smooth race drum you can use the 16 elelement or the 34 element. With the later drums, they are notched to use the 8 roller weak sprag, so you need smooth for either of the dog bone wedge sprags and the 8 roller drum is notched, so it worked similar to a ratchet. Here is a pic of the differences. Also I have a thread running with pics of the Turbo I tore apart of my T400 out of my 86 the way I bought it. It happened to of had a roller sprag failure. I bought a donor trans from a 69 Chevelle that had the good drum with a 16 element sprag, and I just got my 34 element sprag for that drum in the mail yesterday. The set up will be going into the 86 T400 and into the truck. When and if you ever get that thing rebuilt I can get you some info of the good stuff and what you may want to do to it or have done to it. Just don't let someone take your head off to do it. Many places will charge over $1200 for a tranny like I am building. I am probably going to get it done for about $300 that way its looking, maybe $350. So with labor, let a guy make a little money, and do you a good job, you should be able to get it done for $650. Turbo 400 Disassembly Attached Thumbnails Last edited by hotrodpc; 04-07-2009 at 11:54 AM.

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04-07-2009, 09:12 AM	#2
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,149	Are you sure the trans fluid has been brought back to where it is supposed to be? Not likely the converter failed. Anything else could have been damaged though, if you continued to drive it and tried. Anytime you get in that situation and its slipping. Just stop it. Don't try to make it that extra 3 feet slipping the transmission the whole way. That is the easiest way to heat up and wear out clutches and burn steels. Nornally when you have the oposite problem, where it works while cool then warms up and strats to slip, is worn clutches and seals. While the fluid is thicker and cold, the trans seems to work, but the minute the fluid gets warmed and thinner the trans fluid gets around the worn seals, and/or the clutch packs are worn to the point the piston can not travel far enough to compress the clutches and steels to the pressure plate and clamp down to activate that paticular clutch drum. In your case where it is the opposite. It is usually hardened or burnt seals and/or worn clutch packs. The seal is hard, will not flex and the fluid is able to get around the seal not being able to compress the piston... yada yada. As it warms up, the seals become a little bit flexible from being warmed and start to work. In either situation, the trans is short lived. In your case, you can try a trans additive and it may prolong the life a bit longer by conditioning the seals. If the clutch packs are worn to far, there is nothing that can fix that other than a rebuild. Sounds like you may have a short lived trans. Also the line coming off would have only added to the already worn trans. So the line coming off is not what killed the trans as far as damage, but sounds as if it were a weak trans already if it could not handle that, and just the straw that broke the camels back. Do check your fluid level though and be sure you have it correct. That may just fix your problem if you did not refill it enough. Sometimes if its a bit low, as it warms up it expands to act like you have more fluid, so be sure the level is correct.

04-07-2009, 09:55 AM	#3
k20_chevy Senior Member Join Date: Apr 2009 Location: Lorain Posts: 82	Thanks for the quick reply. I did recheck the fluid and always check it almost on a weekly basis. Sounds like I will be replacing the trans at some point. It is my mud truck so not too big a deal. I probably drove it 500 feet after the line come off to get out of the huge intersection. Sounds like my torque converter is fine but my trans is on its last leg. I must be lucky or the th400 trans is really hard to beat like most claim. I've been running the truck with this issue for coming close to a year. With that, could I replace it with a 700r4 trans instead? Oh, and my truck is a 1981 Chevy k20 3/4 ton 4x4 with a 350 engine and th400 trans.

04-07-2009, 10:15 AM	#4
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,149	If it has lasted a year this way, try to add a trans additive that will soften them seals. You just might revive it a bit. The T400 is hard to tear up. Sure it can be done. Is that the original trans in the truck? If so, it doesn't have the good sprag. If you are using it as a mud truck, you want it to be tough, try to find the good sprag drum. If its your mud truck, are you really concerned about the OD??? For what little fuel you will save with the OD, and the added expense of buying a 700r4 and more expensive to build, I'd certainly stay with the bullet proof 400. 700r4 is a weak transmission. It can be modified to have some strength in some areas, but like a chain, if you do not strenfthen all the weak parts, its only as strong as the weakest link. Even if you do get a good 700r4 and you don't break it, it will not last as long as 400. You can get close to 200,000 out of a 400 with some abuse along the way. With some abuse, I'd say you'd be doing good to get 100,000 out of a 700r4. I am in process of building my T400 for my 86 3/4 ton. I wish it were 4x4. I have acquired the good sprag drum and got the 34 element sprag in the mail yesterday. Now I need to order the rest of the kit and I get to start putting it back together. I am doing some trick stuff to it, and it will be bullet proof and able to handle all the abuse I can give it. There are many parts from the 4L80-E that you can add and use on the 400. Like an extra clutch in the clutch packs using the 4l80-E drum pistons, and pressure plates. Also a better designed snap ring from the 4L80-E can be used on the 400 too. Those little things add up.

04-07-2009, 11:16 AM	#5
k20_chevy Senior Member Join Date: Apr 2009 Location: Lorain Posts: 82	OK. I will get some lucas trans. additive this weekend. I not familiar with the internals of the transmission yet. What is a "good sprag?"

04-07-2009, 11:44 AM	#8
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,025	might want to explain what the sprags are and what they do so that he can understand exactly what to look for. i really cant explain it as i am not a tranny guy.

04-07-2009, 11:54 AM	#9
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,149	Good idea, I may do that. For now I gotta run. I just got an email with 7 services to do, so now its time for me to go to work and make some people mad and earn some money. Must be why I like the forum so much. I do not make friends in my line of work.