shrpshot85
Registered Member
I have a THM 700R4 in my blazer now but its in bad shape. Im my suburban it has a THM400 which im plannin on swapping out into the blazer. I need your guys advice on which is the better tranny?
CK5
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which transmission?
- Thread starter shrpshot85
- Start date
StevoandaRedK5
1/2 ton status
700r4 has an overdrive and a lower first gear over the TH400, but the TH400 is pretty much bulletproof if it's in good shape. I think the length and some other stuff would be different between the two and make the swap to the 400 a little more involved than just rebuilding the 700r. What motor does the blazer have?
shrpshot85
Registered Member
The blazer has a 350 but its gone bad. The suburban has a good 383 and good th400 which Imight plan to swap with the blazers 350 and 700r4. I dont really care about the overdrive, its nice but I would like to have a stong reliable tranny. Your right it would cost around 500-700 to fit the 400.
StevoandaRedK5
1/2 ton status
for an automatic, the Th400 is about as strong as it gets for this era of truck. If you don't need the 'burb, swap in the 383/TH400 combo and call it good.
K5dreamer
1/2 ton status
theres always a manual valvebody 4L80 if you dont mind the cost 
get the strength of the TH400 and the overdrive of the 700R4. To me its a great idea. I was planning on doing that swap myself until i learned the wisdom of the NV4500 swap
From what ive read you can even convert a 2WD 4L80 to a 4WD application for a very reasonable investment of time and money. A full manual valvebody eliminates the super expensive computer controls, and you can even wire a switch up to the shifter so in D the converter locks up, and you can retain your lockup converter for highway cruising.
Im just not a fan of the three speed TH400. especially with deeper gears.
get the strength of the TH400 and the overdrive of the 700R4. To me its a great idea. I was planning on doing that swap myself until i learned the wisdom of the NV4500 swap
From what ive read you can even convert a 2WD 4L80 to a 4WD application for a very reasonable investment of time and money. A full manual valvebody eliminates the super expensive computer controls, and you can even wire a switch up to the shifter so in D the converter locks up, and you can retain your lockup converter for highway cruising.
Im just not a fan of the three speed TH400. especially with deeper gears.
