[JJ350]

Guys, I've have a s-1o with a 350 small block and I thought was a th350. Well, when I went to the local parts store to get a new gasket/filter for the th350 it didn't fit. So I went back and the only gasket that would fit, was for a th375?? I am new to hotrodding/automotive in general and I have never heard of this transmission, are they any good??

 

[killerformula]

Another board discussed this

I found something on another board. Sounds like its a TH400 for the most part with a 350 tail shaft?

K

 

[JJ350]

Hey, thanks killer.. Okay, now for my last question sorry if it's lenghty.. I have been having problems with my truck moving when I put it into gear. Last weekend I noticed the passenger side rear brake was binding (the piston was shot and had press the shoes against the drum) I removed the brakes and off my truck went. Problem solved... NOPE. Yesterday I jacked the rearend up and put it into gear and nothing.. The driveshaft would not spin at all. I then went to my local parts store to pick up the gasket/filter mentioned above because I wanted to look at the fluid. Well I found many small pieces of the gasket in the bottom of the pan.. NOT good... I'm afraid the some of these particals have worked its way into the trany. Is there anything I can do to try to get any of this stuff out. I have had the pan off since yesterday hoping that some of this would drain out. Please know that I have no smarts when it comes to tranies. Any help you can give me would be great, I"m trying to figure out the little problem solving things I can do be having to drop the trany, thanks again.

 

[Frisco]

Last weekend I noticed the passenger side rear brake was binding (the piston was shot and had press the shoes against the drum) I removed the brakes and off my truck went. Problem solved... NOPE.

Well I found many small pieces of the gasket in the bottom of the pan.. NOT good... I'm afraid the some of these particals have worked its way into the trany.

Just curious about your first statement. How is removing the brakes solving the problem?

Your second comment however has been answered by yourself. "NOT good". Sounds like you are ready for a complete rebuild /replacement of that trans.

 

[JJ350]

Frisco, Sorry I didn't mean problem solved ,I just thought at the time the reason why my truck wasn't moving was becuase of the brakes locking up.

 

[Frisco]

Frisco, Sorry I didn't mean problem solved ,I just thought at the time the reason why my truck wasn't moving was becuase of the brakes locking up.

No apology needed. I just didn't understand your statement.

Good luck with the trans.

If it was just gasket from the pan you may be OK. Was the trans fluid FULL when you tried to move? If the trans was low that could be the problem.

 

[JJ350]

Is it possible that the filter will stop the debri in the pan from going into the trans? Or is there other places on the trans that draw the fluid from the pan?

 

[JJ350]

Frisco, yes there was plenty of fluid in the trans, I checked it many times.

 

[Frisco]

Is it possible that the filter will stop the debri in the pan from going into the trans? Or is there other places on the trans that draw the fluid from the pan?

Yes the filter should do the job.

Problem at this point is whether the debris is from the pan gasket or the clutch discs. If it is from the clutch discs; then rebuild/replace is next step. If only from the pan gasket; then a good cleaning of the pan and replacement of the filter as well as re-filling the trans fluid may be all that is required.

When re-filling the trans; pour 4 quarts in the trans. Start the engine and while the engine is idling pour in additional trans fluid until FULL on the trans dipstick. Should take about 4-5 additional quarts unless the trans is a new empty one. Total capacity is around 11-12 quarts including the converter, lines, & trans cooler.

 

[JJ350]

Frisco, yes I'm pretty sure the debris is from the gasket. I made a close inspection of the fluid when i drained it and got my hands in there and felt all of the debris and there were no metal flakes of any kind in the fluid. Thanks for all your help. I will put the pan back on tonight and update tomorrow.

 

[sbchevfreak]

I can't remember the exact difference, bu the THM375 is different than a THM350. Lock up designation is THM350C.

 

[JJ350]

sbchevfreak, I don't know much about tranies but I happen to call a local transmission shop and he said a th375 is a TH400 with a TH350 output shaft..
I don't know if any experts will chime in on this..

 

[tnsmith10]

sbchevfreak, I don't know much about tranies but I happen to call a local transmission shop and he said a th375 is a TH400 with a TH350 output shaft..
I don't know if any experts will chime in on this..

a 375 IS a 400 with a small spline (350) tailshaft. dont see too many of those anymore

 

[JJ350]

Not wanting to be this thread to death but is the TH400 the same length as the TH350, just wandering why the made a TH375 , thanks.

 

[Huskinhano]

I use to work in a Chevy parts dept in the mid 70's. Basically the TH375 is a light duty version of the TH400. Same basic trans but I think it basically had smaller clutch packs, meaning less clutch plates, ect. IIRC, I seem to recall a TH425 but I could be wrong. Used in heavy duty trucks.

 

[Crosley]

I use to work in a Chevy parts dept in the mid 70's. Basically the TH375 is a light duty version of the TH400. Same basic trans but I think it basically had smaller clutch packs, meaning less clutch plates, ect. IIRC, I seem to recall a TH425 but I could be wrong. Used in heavy duty trucks.

the t425 is a FWD unit used in the large cars.

T-475 was used in large motor homes.

 

[Crosley]

Not wanting to be this thread to death but is the TH400 the same length as the TH350, just wandering why the made a TH375 , thanks.

t-400 is not same length as a t-350. Trans mount in a different location , different spline output shaft diameter in most t-400


why did GM build the t-375 tranny? You would have to ask GM engineers that.

they possibly saved 1.75 per tranny/car on it

 

[runn141]

t-400 is not same length as a t-350. Trans mount in a different location , different spline output shaft diameter in most t-400


why did GM build the t-375 tranny? You would have to ask GM engineers that.

they possibly saved 1.75 per tranny/car on it

trans mount on a turbo 400 is 5 inches far forward than a 350, they also made a 375b trans, but it is the heaviest duty of the turbo 350s according to the hydra-matic turbo 350 handbook by ron sessions

 

[Crosley]

trans mount on a turbo 400 is 5 inches far forward than a 350, they also made a 375b trans, but it is the heaviest duty of the turbo 350s according to the hydra-matic turbo 350 handbook by ron sessions

that is really wonderful information..... the 375b unit is seldom talked about or heard of by most folks.


I would re-read the mount location information between a t-400 & the t-350 tranny.... or I do not understand what you mean by;

"trans mount on a turbo 400 is 5 inches far forward than a 350"




carry on.

 

[runn141]

that is really wonder information..... the 375b unit is seldom talked about or heard of by most folks.


I would re-read the mount location information between a t-400 & the t-350 tranny.... or I do not understand what you mean by;

"trans mount on a turbo 400 is 5 inches far forward than a 350"




carry on.

sorry about that what i mean is if you have a 350 turbo in a car and you put a 400 turbo in, the location where the 350 crossmember mount was will have to be moved 5inches forward or maybe a little less