What is a fair price to swap a 3-spd manual for a 4l60 transmission in a ‘75 Blazer?
TYIA!
Brad
TYIA!
Brad
CK5
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4l60 swap costs
- Thread starter bradsandersaz
- Start date
You thinking diy costs involved, or paying a shop to do it?
There are 2 methods.
1 intstall an aftermarket output shaft, that allows t case adapter to bolt to trans housing. If you go this route front drive shaft options are slim. I had to used a gen 1 blazer front shaft.
2 use an 1¾ or so spacer between trans and tcase adapter. You will have enough room to run your stock drive shaft.
The tv cable will need a few after market parts depending on fuel system. I recommend checking out Sonnax.
Up grade trans cooler is a must.
What tcase are you using?
Np203 is the normal offering with the 3spd th350 of that era.
I wouldn't hang a np203 off a trans with the spacer.
If you upgrade to an np208 and use the output shaft method you'll have easy front drive shaft choices. Probably need the trans cross member to match.
Lots of possibilities.
1 intstall an aftermarket output shaft, that allows t case adapter to bolt to trans housing. If you go this route front drive shaft options are slim. I had to used a gen 1 blazer front shaft.
2 use an 1¾ or so spacer between trans and tcase adapter. You will have enough room to run your stock drive shaft.
The tv cable will need a few after market parts depending on fuel system. I recommend checking out Sonnax.
Up grade trans cooler is a must.
What tcase are you using?
Np203 is the normal offering with the 3spd th350 of that era.
I wouldn't hang a np203 off a trans with the spacer.
If you upgrade to an np208 and use the output shaft method you'll have easy front drive shaft choices. Probably need the trans cross member to match.
Lots of possibilities.
Its way worse than that, he has a 3-spd Manual.
Np4500 would be the way to go.
Edit missed the manual in the post. Guess my Evelyn Woodhead sped redding corse wasn't worth the money
Edit missed the manual in the post. Guess my Evelyn Woodhead sped redding corse wasn't worth the money
Could also be a Dana 20 case… IIRC ‘74 or ‘75 was the last year for those being used.
I would assume that replacing the T-case with a matching 208/241 connected to a 700R4/4L60 would be easiest option.
If you are going to have a shop do a turn-key job of swapping out an oddball manual trans and adapter to T-case plus pedal assembly, driveshafts, crossmember shifters etc. for a complete O/D auto setup it’s gonna be expensive.
Give us an idea of how you are going about this ?
If doing the work yourself getting a complete donor vehicle will be the easiest way by far.
I would assume that replacing the T-case with a matching 208/241 connected to a 700R4/4L60 would be easiest option.
If you are going to have a shop do a turn-key job of swapping out an oddball manual trans and adapter to T-case plus pedal assembly, driveshafts, crossmember shifters etc. for a complete O/D auto setup it’s gonna be expensive.
Give us an idea of how you are going about this ?
If doing the work yourself getting a complete donor vehicle will be the easiest way by far.
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Were going to need some more info...better yet a picture of the blazer...
Is the Blazer 2wd or 4wd?
What engine is in there now?
Do you already have the 4L60/700r4 transmission you want to install?
Does the Blazer already run and drive now?
Floor shift or column shifter?
Either way I can see the rear driveshaft needing adjustments. Shifter adjustments/swap as well. Hopefully the speedometer cable reaches. This is a good time to swap all the motor/trans mounts as well. TV cable and engine bracket needed as well as lock up cconvertor/TCC switch mods as well.
Is the Blazer 2wd or 4wd?
What engine is in there now?
Do you already have the 4L60/700r4 transmission you want to install?
Does the Blazer already run and drive now?
Floor shift or column shifter?
Either way I can see the rear driveshaft needing adjustments. Shifter adjustments/swap as well. Hopefully the speedometer cable reaches. This is a good time to swap all the motor/trans mounts as well. TV cable and engine bracket needed as well as lock up cconvertor/TCC switch mods as well.
Didn’t even think about it possibly being a 2WD.
2wd drive would be easy
If he wasn't a premium paying member I would have thought it was a bot.
I guess we need to wait a little more for the details
I guess we need to wait a little more for the details
Cost depends if you run them like I do.
I was going to start typing out a list, but have no idea if a 1-post member will ever be back. But you guys are right, the list should be a list of questions at this point. Such as:
Do you really have a 4L60, will it actually be a 700R-4 or will there be a transmission controller?
Do you really have a 4L60, will it actually be a 700R-4 or will there be a transmission controller?
The front shaft is currently not connected.
This Blazer will be a street prince.
We are thinking 4l60 for the 6-spd, (fuel economy) and for freeway speeds.
Shifter question: we’re ok with a floor shifter, would prefer a column shifter but this would require a steering column exchange.
Paying a shop.
I accidentally hit reply.
I would like to preserve the 4x4 option
I’m aware that it needs a controller for the 4l60.
I do not have the 4l60 trans yet but I can get one.
Would a 700R-4 deliver better fuel economy? Over 4l60?
It has a SB 350 and it runs great!
I’m not a bot…
Anyone in Phoenix interested in tackling the project?
Right on.
the sixspeed auto is the 6L80, and you definitly need an expensive computer to run it. The 4L60e is a 4 speed and an elctronic version of the 700r-4.
Your easiest and best bet would be a 700r-4, as that is a bolt-in, no computer deal.
the sixspeed auto is the 6L80, and you definitly need an expensive computer to run it. The 4L60e is a 4 speed and an elctronic version of the 700r-4.
Your easiest and best bet would be a 700r-4, as that is a bolt-in, no computer deal.
4L60 is just a re-naming of the 700R-4, so they have the same gear ratios and many parts interchange. Going to a 6-speed requires a more complicated controller (Or just LS swap it!). Using an old one (early 90's or 80's) is controlled with a cable to the throttle. The "-E" ones are electronically controlled. I made a list of the differences: https://ck5.com/forums/threads/4l60-hydramatic-rpo-md8-tranny-compatibility.351650/post-4421218
For simplicity sake just get a 700r4 and eliminate the need for a computer to run the trans. Like others have indicated the 700 and 4l60eare virtually the same mechanically minus the electronic controls.
However, going to the computer controlled 4l60e can cause a need to figure out how to run your cable speedo. Plus paying a shop to sort it out at a per hour labor cost is going to be stiff for cost.
Ideally, find a 700r4/208 or 241 combo with cross member from a mid 80’s truck/blazer/suburban. That would be a drop in affair that would lower labor cost and maintain the cable speedo. Have the 700 rebuilt with all the right stuff and make sure thy have the tv cable adjusted correctly out they will be pulling the trans again.
The shop won’t have to fabricate anything. It will use a stock front driveshaft for that combo. If you also use a floor shifter, the manual column does not have to be swapped either.
A slight recoup in funds could be had selling the manual parts off the truck too. Pedals for sure.
However, going to the computer controlled 4l60e can cause a need to figure out how to run your cable speedo. Plus paying a shop to sort it out at a per hour labor cost is going to be stiff for cost.
Ideally, find a 700r4/208 or 241 combo with cross member from a mid 80’s truck/blazer/suburban. That would be a drop in affair that would lower labor cost and maintain the cable speedo. Have the 700 rebuilt with all the right stuff and make sure thy have the tv cable adjusted correctly out they will be pulling the trans again.
The shop won’t have to fabricate anything. It will use a stock front driveshaft for that combo. If you also use a floor shifter, the manual column does not have to be swapped either.
A slight recoup in funds could be had selling the manual parts off the truck too. Pedals for sure.
As for gas milage it may not improve much. 700r4 swap is going to change the rpm range you cruise in, depending on ring gear and tire this may put your rpms outside of best power.
I did this swap 15 years a go,
Had a few issues to sort out over the years. Original tire and gear at time of swap, 4.1 and 33s, then 4.88 and 33s, now 4.88 an 37s.
At first cruise was @1600 rpm
To low to pull out and pass with any confidence. My engine begins to make good power around 2400. The 4.88
Rp had my cruise at 2400rpm
With 33s. This was good but my 4th gear lockup was either on or off, only the brake switch would unlock. 4th gear acceleration left a lot to be desired. Just last year I added a vacuum switch to my TCC circuit,when accelerating the torque converter unlocks when the manifold vacuum drops below 6 in hg. This allows the convers torque multiplication to aid and the engine is 250 rpm higher into the power band. I wis I had done this at original install.
I did this swap 15 years a go,
Had a few issues to sort out over the years. Original tire and gear at time of swap, 4.1 and 33s, then 4.88 and 33s, now 4.88 an 37s.
At first cruise was @1600 rpm
To low to pull out and pass with any confidence. My engine begins to make good power around 2400. The 4.88
Rp had my cruise at 2400rpm
With 33s. This was good but my 4th gear lockup was either on or off, only the brake switch would unlock. 4th gear acceleration left a lot to be desired. Just last year I added a vacuum switch to my TCC circuit,when accelerating the torque converter unlocks when the manifold vacuum drops below 6 in hg. This allows the convers torque multiplication to aid and the engine is 250 rpm higher into the power band. I wis I had done this at original install.
That's true, but it's sort of just the general snowball effect of modifying a vehicle. Assuming that everything is set up right, in general going from 3-4 speeds will give you better mileage, better acceleration or maybe some combination of both. There is some efficiency lost going from manual to auto, but that is dwarfed by moving your cruise RPM from 3000 to 2100 (for example). It can also save a lot of ear fatigue. Now whether or not you ever recover the swap cost in fuel savings has been discussed here several times.
One of the better benefits for my heavy ass burb, is the 3.0 to 1 first gear
