TH375 -550HP? and TH350 for towing?

[58Apache]

A friend has a TH375 (TH400 with TH350 output shaft? -came out of a van) and he's worried about his 550HP 468 putting out too much torque for the TH350 tailshaft.

He had a bad experience with a drive shaft in the past and will go top of the line brand name drive shaft for strength. He's about to order the drive shaft. The tranny side requires a TH350 yoke. Any concerns?

Also, I'm about to start on my 58 Apache 1 ton that I want to make a tow vehicle. I have been considering using a 4lL80 if I could find one cheap enough. I think I found a Diesel 4L80 (non E?) In the ad he says the diesel version is geared differently?

I have a TH350 I can use, and my friend above said he talked to a tranny builder that raced with a TH350. So if I have the TH350 built right will it handle towing a car on a trailer ok?

                                   Steve

[Crosley.In.AZ]

the t-375 has 1 less frictions in the clutch packs : forward and direct drums... unless a person changed that.

The 4L80E was NEVER built in a non electronic version.

[Crosley.In.AZ]

as i re-visit this thread.

the 4L80e was not geared different in a diesel application.  i often where these silly ideas start at on the internet

the 4L80e can be converted to non electronic setup.  this requires full manual up shifts and down shifts.. there is NO automatic mode

[58Apache]

The guy that was selling the tranny put that it was "geared for a diesel" in his ad. I didn't know there if there was a difference or not so I posted here to get the real answer.

Is there something I could use to run the electronics in a non-computer truck?

[Crosley.In.AZ]

The guy that was selling the tranny put that it was "geared for a diesel" in his ad. I didn't know there if there was a difference or not so I posted here to get the real answer.

Is there something I could use to run the electronics in a non-computer truck?

there are several stand alone computer systems to control these electronic transmissions with a standard carb'd   engine ... these often use a cable setup hooked to the carb linkage just like a regular TV cable from a 700r4

www.compushift.com  have a very nice unit.  There are cheaper units / brands out there.

[58Apache]

Here's the exact ad the guy posted:


"Trans is out of a 1994 chev 1 ton.I converted from a gm diesel to cummins power and used the chrysler trans. The 4L80 was in good working condition when i took it out .It is the diesel geared trans 350.oo "

[Crosley.In.AZ]

Here's the exact ad the guy posted:


"Trans is out of a 1994 chev 1 ton.I converted from a gm diesel to cummins power and used the chrysler trans. The 4L80 was in good working condition when i took it out .It is the diesel geared trans 350.oo "

the guy simply does not know.... the 4l80e is shifted electronically   , so the programming in the on board systems shift the trans as needed for the diesel engine.

Diesel transmissions  are shifted at lower RPM .

A 1994 trans 4l80e would have the early design cooler lines. They are together near the bell housing like a t-350 , t-400 , t-700 trans.  I think 1994 is the year the wire harness connector design was updated to a better connector that did not leak like the early design did.

[58Apache]

Thanks Crosley. So if you were building a truck for towing, would you go for the 4L80E?  I'd have to go out and buy one.

Or do you think my TH350 will do the job if I cool it well enough? Maybe I could get a TH400 cheap?

                                         Steve

[Crosley.In.AZ]

The answer depends on how heavy of a load being towed..

I towed a bunch of stuff with my 1971 Chevy truck... ZZ4 engine - t-350 transmission. If there was a heavy  loaded trailer hooked on the truck .....EVERY shift was a manual shift  I made.  I started in manual first gear and shifted the trans each time.  At 90k miles I pulled the trans apart for a freshen.  Except for bushing wear , the internals were in excellent shape.


Towing a heavy load using a GM power train ;  I would use a t-400 if possible.   They are just a tough , simple  transmission.  Gear vendors is an option for over-drive.... a bit pricey at 2500 bucks or so.

The 4l80e with a controller gets expensive is a reason I stay away from them, that is simply a person preference thing.  Around here a core 4l80e can cost 350  to 500 bucks  or higher.  Spend $1000.00 on rebuild parts , converter , internal electronics without any labor to build the trans.