View Full Version : tth350 to th400 swap
valmet12
11-21-2003, 02:59 PM
i've been think about switching out my th350 to a 400. i am wondering what it would take to switch it over. It is a shortbed half ton with a np203 transfer case. also would it be worth the trouble? what about switching to a 700r4?
wyldman
11-21-2003, 03:06 PM
It can be done,using either stock parts,or aftermarket adapters.
If you get a TH400 4WD trans,you can get an adapter from advance adapters to bolt it up.I don't think you need to modify the driveshafts for this swap.
You can also mate the 700R4 to the NP203 via an adapter,but you do need to rework the driveshafts to make it work.
You could also get stock parts out of a donor truck to make it work as well.
Try www.advanceadapters.com for more info on the adapters.
Something to think about is that the 700R4 has a lower first gear than either the TH350 or TH400. It makes a big difference in starting effort either plowing or towing. And while the 700R4 has a bad reputation, the later ones are as good as any of the series. The R4 can be built into a very stout transmission, talk to John DiMartino about that.
sonjaab
11-21-2003, 05:26 PM
700r4........Forget it !
I smoked 4 of them on my 90 GMC. All under warranty
thank god ! 1 driver truck too................
My 94 & 97s with the 460 or 480 le ? trans. NEVER a
problem with them plowing. .........geo
Joey D
11-22-2003, 03:47 PM
sonajaab, If you smoked 4 700's they were not built right or you are down right abusing them. The 700r4 can be made to hold more power than most here will make. They will break when abused or not maintained, like anything
JohnnyU
11-22-2003, 09:43 PM
I have a rebuilt/beefed up 700r4, I couldn't be happier with it. If they are built right, they're darn near bullet proof, plus the lower 1st gear and overdrive are very nice for a daily driven truck!
sonjaab
11-23-2003, 03:48 AM
I don't know guys............My 2 TAs had R-700s and I
never fried them. My GTO has had the same th-400
for at least 10 hard drag racing years with the stall
converter, line loc, and slicks etc......Now just a stock
converter for Sunday crusin' !:burnout
I just had LOUSY luck with them in my 90 GMC....
and have never replaced a trans. in my newer rigs.
..........geo
JohnnyU
11-23-2003, 09:31 AM
I thought Camaros, GN's, Regals, T/A's etc had the 200r-4's in them? Slightly different animals, but similar in many repects.
W-n-K Landscaping
11-23-2003, 12:33 PM
When I worked for Verizon- the bucket trucks they bought in the '90's all had the 700r4 tranny- and some of those trucks saw almost 200,000 miles! The transmissions were great, and they saw a lot of hard heavy use on a daily basis- they also saw a lot of idleing time since most guys did not shut their trucks off in the winter. I would say that with regulal maintenence done- especially after a hard season of plowing, the tranny should last a long time.
Bill
Joey D
11-23-2003, 03:25 PM
Bill, A 700 in a bucket truck? Unless they were 6 lug wheels it would have had the 4l80 in them.
W-n-K Landscaping
11-23-2003, 03:32 PM
I could be mistaken, but I coulda swore that the mechanics told me it was a 700r4. Well, I know that currently I do have a 700r4 in my Chevy Blazer, and it is running great so far!
Bill
teeca
11-23-2003, 05:00 PM
after i had my 700r4 rebuilt using the 4l60e clutches, it hasn't had problem 1, and the 700r4 had 124K before rebuild, now i'm @ 168K and still going, shift kit, works great!
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