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tranny conversion?


cheese's Avatar
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01-25-02, 12:02 AM   #1  
tranny conversion?

Hi Joe, and everyone! I have a question about converting transmissions. I have a '85 chevy scottsdale p/u truck with a THM350 w/lockup converter in it. Something started whining on decelleration in 1st gear. I think a needle bearing and/or planetary gearset is going out. It has every right ...with over 200k on it. I am entertaining the idea of installing an overdrive transmission. Question is...can I do it without changing mounts, brackets, linkages, flexplate, driveshaft, etc...? What is your opinion of the 700R4 tranny? Any reasons not to do the swap? I've pulled and installed many transmissions, but never switched around models.

 
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01-25-02, 11:11 AM   #2  
Joe_F
Cheese.

Yes, it can be done. And probably relatively painlessly from what I recall.

Make sure you get a rebuilt tranny. The early 700R4's (pre '89) were weak and suffered from premature pump failure.

I know someone makes a kit to retrofit this, but it's mostly all there. Might need something to hook up the lock up solenoid.

Give the folks at Level 10 or Rostra Precision Controls a call. They have surely come across this before.

This is a popular and wise thing to do. I'll try to find out more for you if I can.

The truck will be faster, better and get better fuel mileage. A well built 700R4 rivals a good THM350.

 
cheese's Avatar
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01-25-02, 10:27 PM   #3  
That's what I wanted to hear! I'd love to squeeze a little more economy outta this truck. For a while I was ranging from 19 to 21 mpg on hwy with it, until the lockup converter quit locking. I just freshened up a 305 and dropped it in a few months ago, figured the tranny wouldn't be far behind, lol. I'll post if I run into trouble with the swap. THX!

 
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01-26-02, 04:21 PM   #4  
Joe_F
Let us know what you find...

Do a search on THM350 to 700R4 conversion in www.google.com

Likely to get a lot of hits and tips when you do.

 
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