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Discussion Starter · #1 · (Edited)
Just had an old step van with a 6.2 pre-purchase inspection done and the mechanic who did it said I can't turbo a 3 speed.

They said the top speed in this old step van postal truck would be 55 max. So knowing I've seen threads here about turboing it I asked and then she said you can't because it's a 3 speed. Is that right? I never thought about the different transmissions that might be in the different 6.2's.

This is located 6 hours from where I am so before going down there I thought I'd have it checked out.

List of the problems they found:
  1. The tires are split & dry rotted
  2. The fuel line on the passenger side of the vehicle is leaking in the frame
  3. The transmission line is sweating at the compression fitting
  4. The hanger bearings are dry & rotted
  5. The front brake pads look like new but the rotors are cracked & the slides are seized
  6. There is no brake fluid in the master cylinder at this time.
  7. The power steering belts are squealing
  8. There is rust on the frame
They said 2000-2500$ to get it out the door.

They didn't drive it so that's all I know. Seller said he wanted about $4200 for it (the cost of a storage unit to replace it).

Their last email to me:

Unfortunately you are looking at $2000 to $2500 to start. The mechanic thinks about $3000 is all its worth. Also getting the parts for this arent readily available so if you break down you may not be able to get the parts to repair it. Also it isnt worth the money to put a turbo on this engine because its only a 3 speed transmission. The mechanic said no because its not with the money & its to old.

Are they right or should I ask a different mechanic?

And is a 3 speed the TH400?

It's an old '87 Chevy P30 step van. Hoping to convert it to a mobile home.
 

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The 3 speed is a TH400.It’s an excellent transmission but lacks the overdrive gear for better fuel economy and lower engine rpm at cruising speeds.

Just because it’s a 3 speed does not mean it cannot be turbocharged afterwards.
 

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I had an 84 P-30 with a 6.2L diesel in it, put over 200K on the motor.
Transmission is like a TH400 but with straight cut gears to handle the torque I think the trans shop in my route said it was a TH425 or maybe TH475 (I Think) it's been 31 years since I got rid of it, so many many nights have passed so I think the was the model of it.
No power in that van, square front end didn't help on it. Turbo would of helped a lot.

I thought about putting a Gear Vendor OD on it to get better mileage on it, I was getting 7-8 MPG on this P-30 with 16,000LBS loaded.
 
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I turbo'd my truck with a 3 speed turbo 400 🤷‍♂️ This thing could have a TH400 or a TH475 (the super HD one).

No way I would personally pay that kind of money for an old P30, but that's me and I'm sorta cheap. Most everything mentioned I believe you can get still. Not 100% sure how P30 specific a few of the parts are.
 
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