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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Ziptar on July 07, 2005, 06:26:00 AM

Title: Lose the Lockup on a TH350??
Post by: Ziptar on July 07, 2005, 06:26:00 AM

My 85 2wd has a TH350 Lockup Trans in it. The parts clerk says it's an 84 and a half but, what ever.

I am looking for a cheap "rebuild" trans for as the current one leaks and slips, ALLOT!

One shop I called yesterday said he had a "slighty used" TH350 short tail on the shelf for $100 with a 90 day warranty, He said if I brought it down he'd put my long tail shaft on it. Problem is that it's an early non-lockup trans.

I don't really need a lockup as this truck is mostly for dump runs. So my question is, What kind of installation hassles would I be looking at goeeting rid of the lockup?? or none at all, just leave the wiring for it dangling??

Title: Re: Lose the Lockup on a TH350??
Post by: Blazin on July 07, 2005, 08:48:00 AM

He is going to rip both transmisions all apart to swap in your longer tail shaft? If its going to be torn down that far wy not rebuild it, and if he rips it all apart it could cause problems in the new one, and you won't know until you do all the work of installing it.
I would loook for the correct one save allot of hassle.

Title: Re: Lose the Lockup on a TH350??
Post by: roundedline on July 07, 2005, 09:27:00 AM

Ditto!  I personally wouldn't let them swap parts off of yours onto a rebuilt one.  I would want the rebuilt one to have a the right pieces so it would be a direct replacement.  

As for the lockup vs non, you can do without it.  It will drop your RPM's about 400rpms when it locks, so you would loose that if you swapped.  You can swap a non locking TH350 in its place though.  Dimensionally they are exactly the same.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

Title: Re: Lose the Lockup on a TH350??
Post by: Ziptar on July 07, 2005, 10:17:00 AM

Thanks for the input guys, good point on tearing it apart to swap the tailshaft.


I got a price on a rebuilt from advanced auto parts they get $595 for them. little more than I want to spend on an $800 truck, that I just use on weekends.

I have a call into another shop, he is looking to see what he has, he said he will also give me a price on "refreshing" my tranny.

Title: Re: Lose the Lockup on a TH350??
Post by: roundedline on July 07, 2005, 10:34:00 AM

$585!  EEK!  That it high!  I would think more along $250 for a TH350, at least around here.  That price would get you a 700R4.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

Title: 700R4
Post by: junkyarddog0326 on July 27, 2005, 09:16:00 AM

Yeah, I have a 700R4 in my 84LWB 4x4.  Gotta get rid of it.  TH400's go for cheap in the used market, and are cheap to "refresh".

Title: Re: 700R4
Post by: jo3y1nf4nt3 on July 27, 2005, 01:55:00 PM

i have a TH400 (i've been told).....what are some specs on it.  does it have a 'lock-up' and if so, what is it?  is there any kits that could possibly transform it into a 4speed?  or any tips/tricks for it?  thanks, joey.  

Title: Re: 700R4
Post by: roundedline on July 27, 2005, 03:00:00 PM

TH400's don't have lockup.  You can add it, but it would probably be expensive.  It is a Heavy Duty Transmission.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

Title: tranny
Post by: ChevyGuy on July 28, 2005, 11:40:00 AM

If you are doing dump runs with the truck and you arent worried about the lock up I would switch to atleast a th350. the 700 wouldnt last long with heavy loads..... unless built by a good tranny person who knew about the problems the early 700's had.