350 trans to a 700 should I, or shouldnt I????

[Mr.Scary]

sorry but this might be a dumb question but I have a 89' burban with a newly rebuilt 700 tranny in it and i would like to put it in my 84' truck which currently has a auto350 in it. My question is will everything bolt up? what all do i need to do this swap? parts? etc. and is it a good idea? there is nothin wrong with the trans that is already in the truck but just thought a 700 is better than the 350. any and all comments are encouraged and welcomed.

thanks in
advance guys.

[arkracing]

well, you'll get the overdrive from the 700R4. The main problem is that you need a way for the converter to lock up when the tranny is in overdrive or you'll burn it up rather quickly. You can get a kit that will work off your brake light switch from Bowtie Overdrives or TCI. I would also suggest getting the TV cable adjusted properly by a qualified trans shop, prior to driving the truck regularly.

Does the '89 use a mechanical speedo or a electronic? - if electronic, you'll have to have that changed over

[Mr.Scary]

hmmmmmmmm idk if its mechanical or electric, but this already sounds like a lot of trouble

[63chevyll]

not really. 89 Burb should be Mechanical.

Hey ARKRACING...... Why would the trans burn up if the TCC isnt used? If its not used, the only thinhk thats lost is the TCC, and no performance or pressure is needed for any other part of trans....Hopethat made sence

[Mr.Scary]

i talked with a guy from a local speed shop and he said the only thing i would need i the TV cable that was mentioned early by arkracing so i dunno

[arkracing]

The TC is designed to lockup in 4th gear (which is computer controlled in your burb). You can run them without it but it effectively makes the TC "slip" when in 4th gear.

The kit isn't that expensive and not that hard to install - Cheap insurance if you ask me.

Lot's of guys run without them, but I never seem to hear how long the tranny lasts

[rfmaster]

Originally Posted by Mr.Scary

sorry but this might be a dumb question but I have a 89' burban with a newly rebuilt 700 tranny in it and i would like to put it in my 84' truck which currently has a auto350 in it. My question is will everything bolt up? what all do i need to do this swap? parts? etc. and is it a good idea? there is nothin wrong with the trans that is already in the truck but just thought a 700 is better than the 350. any and all comments are encouraged and welcomed.

thanks in
advance guys.

The 700R4 and TH350 share a 27 spline yoke.
You'll need to measure TH350 tail shaft housing - if its 9-1/4" you will not have to worry about driveshaft shortening. 700R4 overall length 30 3/4" while th350 is 30 5/8" (w/ 9-1/4" tail shaft housing)!
Both 700R4 & TH350 use the same trans mount.
Gear selector linkage is the same, but linkage adjustment will need to be done.
Trany oil cooler lines interchange with some minor massaging.
You will have to move the trans cross member approximetly two inches back and re-drill frame mount cross member holes or if you're lucky factory may have done this for you already.
Spedo cable will bolt to 700R4 driven gear housing.

Other fine details - TV cable, KS wiring to be looked at.

//RF

[Jonboy]

in '84, there should be TCC wiring. It should plug in to the 700 just fine.

[Mr.Scary]

idk all this tech talk is making me not want to even entertain the thought of even doin this! LOL

[James McClure]

Hay guys. Pay attention to this, it may save you a bunch of money. The 350 is a good trans, the later 700's are also good and give you the added benifit of improved MPG's. Do the swap, BUT, make sure to hook the TCC up AND, make sure it works correctly.
The biggest enemy of a transmission is heat, and you guessed it, the biggest source of heat in an automatic is the converter. ALL TCC transmissions have a restriction in the valve body that slows down lube and cooler oil because the TCC eliminates most converter generated heat and will run to cold. If you eliminate the TCC the trans will run hot, to hot. As was mentioned before, you can run without it, but the trans will fail prematurely. The wireing kit is cheap insurance. You can also wire in a switch that turns the TCC on earlier which saves you more in gas, BUT, don't forget to turn it off, the engine will stall just like a manual trans would if you don't release the clutch. Jim

[Mr.Scary]

what does TCC stand for?? LOL just courious

[Adams74Chevy]

Originally Posted by Mr.Scary

what does TCC stand for?? LOL just courious

Torque Converter Controller I am assuming.

[rfmaster]

Originally Posted by Mr.Scary

what does TCC stand for?? LOL just courious

TCC = Torque converter control (lockup). The increase in transmission fluid temperature when TCC is not engaged is not that significant, but should be taken into account. Most truck ECM calibrations call for TCC lockup above 44MPH and steady throttle. At highway speeds there is sufficient air flow to cool transmission fluid, although additional heat exchanger(s) is(are) always a good idea especially if towing under high ambient temperatures. I have been running my 700R4 conversion without active TCC control (this will be rectified soon as I want to better my HWY millage) without any adverse affects on my trany for over 3 years now. My Trany also has a deep extra 3 qt cast aluminum pan for increased fluid capacity.
However, the key to transmission longevity is that elevated transmission fluid temperatures will shorten its life! With TCC engaged torque converter fluid coupling losses are eliminated and amount of energy dissipated into transmission fluid is reduced.

If you seek HWY gas mileage improvement 700r4 is worth the upgrade (especially if TH350 needs work).

//RF

[Jonboy]

Torque converter clutch.

[Mr.Scary]

well its not even that better mileage im looking for and there is nothing wrong with the 350 i have just always heard that 700 is alot better than the 350 because of the overdrive. I kinda just figured i have one in my parts burban collecting dust so i might as well put it on

[munger]

ya the 700 is better cause of the overdrive thats it the 350 is way stronger and can handle more abuse thats why they didnt put the 700 in 3/4 tons or 1 tons cause it cant handle it until 91 they used the th400 in 1 tons and 3/4s and only had the 700 in halfs

[rfmaster]

Originally Posted by munger

ya the 700 is better cause of the overdrive thats it the 350 is way stronger and can handle more abuse thats why they didnt put the 700 in 3/4 tons or 1 tons cause it cant handle it until 91 they used the th400 in 1 tons and 3/4s and only had the 700 in halfs

700R4 (especially early production years 82-86) in its original build form should not be compared to TH350. Over the years 700R4 weak points have been addressed and early units can be retrofitted and upgraded with later parts. For the sake of discussion 700R4 can be upgraded with 4L65e hard parts and improved clutches (there is a build list somewhere in trany forum for stout 700R4 build) to handle a hot street engine or HD towing. While TH400 strength is legendary it takes more power to transfer engine output to the drive shaft. Unless there is a real need for HD hauling DD will do better with upgraded 700R4.

//RF

[staggerd86c-10]

do it the 700r4 tranny in good condition is a great cruising tranny. You never mentioned exactly what you wanted the truck for, round town cruising, daily driver, or racing. if your looking for high performance the 700r4 wont hold up unless you really beef it up. but if your just going to cruise around with the occasionall mashing of the throttle the 700r4 should be good. the TV cable is the only thing you really need, as for the lockup or tcc i believe you can just run power and ground and be able to switch it on and off in the cab. if not dont hook it up it wont damage the tranny it just wont lock up in 4th gear.

[larrystone]

If the truck is not going to be used for any real towing it would be easier to just swap the entire rear end brake drum to brake drum with one with a 2.73 ratio.

My truck with a th350/2.73 turns 2100 rpm at 65 mph.

If you have 3.42 gears with OD your truck will turn 2000 rpm at 65 mph with 28 inch tires.

[Mr.Scary]

Well its only a DD and I rarely ever even have anything in the bed let alone haul stuff. I just really use it to drive to work and back everyday and run my errands in it thats about it.

[N2TRUX]

700 has a lower first gear and OD. The benefits are worth it in my mind.

[larrystone]

I just can't see where a lower 1st gear is going to be even noticeable in an empty truck in a location with the steepest grade at maybe 2%.

[joe231]

lower first gear=greater torque multiplication=faster off the line for stoplight to stoplight=just plain fun!

go with the 700R4, one wire through a multiple contact brake switch and a toggle will give you all the control you need. IIRC, The converter will only lock in 3rd and 4th so you can just leave the toggle on. The extra contacts in the brake switch will unlock the converter when you mash the brakes. and you can turn the toggle off when you want to "mash on it".....or do it like factory, the a fore mentioned brake switch and a vacuum activated switch on the firewall that will allow it to lock the converter under high vacuum condition (low throttle, like while cruising) and will disengage the converter in a low vacuum condition (moderate to heavy throttle, like "while mashing on it"). It is really cheap and simple....


or you could just give me the 700R4 and I will put it to good use

[63chevyll]

logging about 10,000 Miles on my 700r4 in my Chevyll with no TCC whatsoever, and still going strong

[Mr.Scary]

Hmmmmmmm makes me think????? LOL