700R4 Questions

StepSide88 · Jan 8, 2022

I've inherited an '88 Chevy C1500 5.7L Stepside. The transmission cooler lines were missing. I got some trans cooler lines from a friend; however, for the life of me I cannot figure out how to route them correctly. So I was thinking maybe I will just replace them with some 6AN PTFE hoses and appropriate connections.
Question 1: Has anyone done this? And/or would you recommend this?
Question 2: The fastener/bolt for the vehicle speed sensor is missing. What size of fastener/bolt do I need to replace it?

Thanks in advance for your answers and suggestions.

Frank Enstein · Jan 8, 2022

I never recommend AN hoses for trans cooler lines. I recommend hard lines every time.

Get 2 10" lengths of premade 5/16" lines. Use these to get from the trans to around the bellhousing. Put a coupler on each.

Get 2 more lines to go from the radiator to near the bottom pulley on the engine in whatever length that is. Put a coupler on those too.

The last two lines will connect them all together. Get 2 of whatever length is needed.

Plumb them bottom to bottom and top to top. This will purge any air bubbles out of the cooler.

Doing it this way eases maintenance and makes bending them easier.

The copper nickel lines are really easy to work with, can't rust, and if you're careful, can be bent with your thumbs.

df2x4 · Jan 8, 2022

I converted to 6AN lines and fittings from Russell when I had the 4L80E swap done in my red truck. It works fine, but I'm actually thinking about removing them and going back to hard lines eventually just for peace of mind and longevity. The Russell 6AN stuff was expensive, I remember I spent more on hose and fittings than I did on my junkyard 4L80E. Plus it's kind of a pain to keep the braided stainless line from rubbing against things it shouldn't.

If/when I go back to hard lines, I'm probably going with stainless ones from Inline Tube. As long as you don't have an AUX cooler, it looks like they have the correct lines for your '88 C1500 in stainless for $75.

https://www.inlinetube.com/products/sctt8801

Frank Enstein · Jan 8, 2022

I'm not a fan of pre-bent lines unless you are doing a frame-off build. They can be very difficult to install.

Schurkey · Jan 8, 2022

It's CRAZY to use hose where metal tubing will suffice. Proper metal tubing--usually double-wall seamless steel--is less expensive, more durable, lighter, less-easily damaged by road debris, less porous than "rubber" hose including rubber covered by stainless steel braid.

As said, the newer copper-nickel alloy is easier to work with, but costs more than seamless steel.

Consider grabing cooler tubes from a TreasureYard vehicle.

Erik the Awful · Jan 13, 2022

If you can't figure out how to route the existing lines correctly, check to see if they're bent somewhere they shouldn't be.

Nad_Yvalhosert · Jan 13, 2022

Rockauto sells them in prebent form. Used them on my '00 Yukon 4L60, and my '95 2500 4L80.
Correct bends, easy to install, all fittings included, roughly $35 each. It's a no brainier

700R4 Questions

StepSide88

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Frank Enstein

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df2x4

4L60E Destroyer

Frank Enstein

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Schurkey

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Erik the Awful

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Nad_Yvalhosert

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