Turbo 350 vs. 700r4.....

Nissan11

Nissan11

Well-Known Member
Joined
Nov 29, 2005
Location
Marston, NC
I need a transmission for my 85 k5 Blazer which is auto and 4x4. I can get my 700r4 rebuilt for $450 or I can get a 350 turbo w/ conversion kit for $550. I understand that the 350 is a 3spd where my 700r4 is 4spd. Which transmission will take more abuse from towing and off-road use? Since the 350 is a 3 spd is the gear ratio taller which would put more strain on the motor to turn the tires? Thanks!
 
The K-5 is a full size blazer, so it should have a SBC in it. The th350 is a direct bolt up. and you can get a 205 t case to go behind it. IMHO the 350 is much stronger, and you can build it for less than half ($200) the 700r4 is an AOD and has a reduction in the final drive(OD) so yes, your engine will spin more RPM's with a 350. Depending on your tire size and axle ratios will depend on how fast it will turn.
 
a 700R4 is basically a 350 with an overdrive unit. When you tow, leave it OUT of O/D though.

I would rebuild the 700R4, and not focus on the cheapest rebuild, but the one that addresses the most.
 
Rich said:
a 700R4 is basically a 350 with an overdrive unit. When you tow, leave it OUT of O/D though.
There is a lot of differance between the two trannys . I have never seen a 700R4 hold up as good as a 350 . Big tires or a lot of towing will take a 700R4 out.
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get the th350.. trust me you will be better in the longrun. every 700r4 i have seen has given more problems than anything. you wont get the gas mileage you get now out of the th350 but the 350 will be alot better for what you are doing.
 
yager said:
don't forget 700r4 has a lower first gear.
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And if you want to match that first gear and still use the TH350, you can do it for about $125 more. Clarks Racing transmissions in Chesnee SC will do you a great job!
 
I had anopther one of my infamous long posts ready to go and said the heck with it.

Short version

700R4 s
SUCK A$$

End of discussion
 
Have you checked into a 400 tranny? They are much stronger than either the 700 or 350. If your main use is towing and off road then I would suggest the 400.
If it is your daily driver and you don't plan anything extreme I would suggest a quality built 700R4. I've got a 700R4 from www.700r4.com and love it. I have the level 3 in my 3/4ton Sub and I've never had any trouble out of it, though I plan on replacing it with a 4L80e sometime in the future.
You could possibly get a 700R4 from GM and get the 3 year warranty.
Cooling is a must with a 700r4. Get the biggest tranny cooler you can if you decide to go this route.
 
Thanks for the advice. Tomorrow Im going to drop the transmission. Am I going to have to remove the t-case and also once everything is unbolted and ready to go, will the torque converter nd the flywheel slide out with the tranny? Thanks.
 
unbolt the torque converter from the flexplate(flywheel) to remove the tranny
Once out, the torque converter will come out of the tranny
 
Do I unbolt the torque converter from the flywheel while the tranny is tight against the motor or do I need to slide it out a little bit first?
 
pull the inspection cover from the bottom of the tranny, take out the bolts that hold the torque converter to the flexplate. Then seperate the tranny from the engine. No sliding it out "a bit"
 
you can leave the TC bolted to the flywheel, the tranny input shaft will slide out of it just fine, assuming that the transfer case is out. make sure you unhook the detent cable, i have broken quite a few of them. oh and for the replacement tranny, dont go near a 700 unless you like pain, cause they can be a huge one. th350s are very simple and easy to rebuild, much better than the 700's. dont listen to rich, he only knows about mall cruzin his cruiser :flipoff2:
 
hey, at least my shit runs... :flipoff2:
 
Go with the 700r4 I hava 4l60e(same as 700r4 but electric and I love it) I run 35's and 4.56 lockers with no issues. you get a better 1st gear and you have overdrive for the hwy
 
AV8 said:
Have you checked into a 400 tranny? They are much stronger than either the 700 or 350. If your main use is towing and off road then I would suggest the 400.
If it is your daily driver and you don't plan anything extreme I would suggest a quality built 700R4. I've got a 700R4 from www.700r4.com and love it. I have the level 3 in my 3/4ton Sub and I've never had any trouble out of it, though I plan on replacing it with a 4L80e sometime in the future.
You could possibly get a 700R4 from GM and get the 3 year warranty.
Cooling is a must with a 700r4. Get the biggest tranny cooler you can if you decide to go this route.
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Yaeh I got the 4l60e straight from GM and a 3 year 50k warenty. I got the shop discount and it was $1270 but worth it.
 
What I didnt notice before are the wires or cable that is going into the ttransfercase. How Can I remove the t-case or drop the tranny without breaking those wires. They enter the t-case on the upper passenger side.
 
Nissan11 said:
What I didnt notice before are the wires or cable that is going into the ttransfercase. How Can I remove the t-case or drop the tranny without breaking those wires. They enter the t-case on the upper passenger side.
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there must be a plug or a connector some where
 
Metto said:
you can leave the TC bolted to the flywheel, the tranny input shaft will slide out of it just fine, assuming that the transfer case is out.
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Not a good idea.

You have to pull the tranny back far enough to clear the pump shaft and you risk damaging the pump, input shaft, etc.

Unbolt the converter from the flexplate. Then it only has to come back far enough to clear the dowel pins and the hub on the front of the converter.
About 1.5"

Same going back in. Put the converter in the tranny then install together. You will not get the tangs for the pump drive to line back up with the converter if you put it back in 2 pieces.

I use a set of pump pliers (channel locks) to grab the flexplate and turn it to get at each of the bolts. It is easy enough there is little excuse not to.

Otherwise - good advice about the detent cable.
I have forgotten a couple of them too.
You can either remove it from the throttle linkage bracket and snake it out with the tranny, or drop the pan and remove the clip and link from inside, then pull the retaining bolt and cable out and leave it in the vehicle.

I also leave the dipstick tube in the vehicle until the tranny is out.
 
Ridgerunner said:
there must be a plug or a connector some where
Click to expand...

TV cable drop pan and you will see where it hooks up it will slip out of its retainer

Now as to strength, stock for stock, I will agree that the 350 is slightly stronger. Properly built (and don't believe the hype this can be done for under $500) they can be made as strong as a stcok th400. You need the 10or11(I think mine was rebuilt like 4 years ago)vein front pump and the corvette or otherwise beefed 2nd gear servo. plus a few other internal mods

The guy who did mine modified the valve body and recomended MERC V fluid when he was done. 12000 miles and numerous hard wheelin runs later the 38.5s still spin she is decent at cruisin speed thanks to the reduction of OD

I am happy with the 700r4 and would never swap it for a th350, a th400 thats another story.

As mentioned before, YOU MUST KEEP THEM COOL and an improperly adjusted TV cable (it is not a kickdown or detent like on a 350) can smoke them QUICKLY

If you want the 700 redone PM me I can hook you up with a guy who will make it right and cheap!
 
Ok I want to drop the pan to remove the cable, the only problem is the jack is supporting the tranny by the pan. I cant put a jack under the t-case because I took it out. Any ideas?
 
Alright I got the cable out by stacking blocks under the back of the tranny and moving the jack out of the way. I put the pan back on but I dont know how the dip stick body comes out. Should it just slide out? I tried wedging it out with a flathead but there is a rubber seal I cant get past. Thanks! After this comes out the transmission should slide out.
 
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