TrailMaster Lift Help

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Wlfman

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Hello,

I recently acquired a 1990 GMC Sierra SLE SCSB with a 4" Trailmaster lift P/N C44 on it. Took me a while to figure out what was on there, as they evidently don't make this lift anymore. I have worked on older pre-87 trucks before but this is my first 400 model, not to familiar with the torsion bar trucks.

My initial goal was to strip it down replace any bolt on part on the frame and go through the motor, trans and transfer case. I have the bed off now and everything removed on the rear end but the suspension parts and I am getting ready to remove the doors, hood and fenders. All will be replaced with new sheet metal, as well as rockers and cab corners and a small hole in the floor pan.

This brings me back to why I am posting. What are my options with this lift? I know that based on what I have been able to research the lift replaced the front differential frame support. Can I remove the lift blocks in the back and find a front diff support in a junkyard and return this to stock? If not can I get smaller blocks in the back and somehow decrease the amount of lift in the front?

Before I hear "why did you buy the truck like this to change it" it was less than 500.00 and running... I have a 4.5" lifted Jeep Unlimited on 35's so I wanted something to haul stuff with and get me through MI winter snow and this truck won't be taken off road except for hunting roads and such. I have the mechanical ability to rebuild all parts of this truck just not sure what to do with this lift.....
 

Wlfman

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77 people viewed and not one response....

Lets try this, can I change to shorter blocks in the back and turn the front keys a little to take some of the lift out? Or, will i loose to much ground clearance due the drop bracket for the back end of the torsion bars????
 

Shorty01GMC

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Surely you could turn the front down to level out the cv axles for best wearability of parts, then ad whatever size block to make it leveled, raked, or squatted... I would consider replacing ball joints, tie rod ends, idler and and pitman arm, idler arm bracket, and possibly control arm bushings if they are worn.. I’m pretty sure the upper control arms will be aftermarket.. my old trailmaster kit on my k2500 has trailmaster upper arms and I used factory ball joints in them.. I raised my truck up in the front from where it was when I purchased it.. it is slightly higher in the front than back and I plan to swap to a taller block...
 

Wlfman

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What size should I be looking at? The truck came from the factory with the Z71 Off-Road package (which I know is irrelevant now) so I was planning on getting Bilstien 4600's to replace the rusted out (and 1 has a hole in it) shocks that are on there.

If I keep it at 4" what size shocks (or part # if you know) if I lower it to say 3" what size do I need?

All front end steering and suspension bushings will be replaced during this rebuild. I don't know what the truck has had done to it and I want to start out with everything new. The entire rear end will be rebuilt with new springs, bushings, all mounts for springs and shocks etc.. Basically if it can be taken off and replaced it will be. The only original parts will be the frame and the cab shell and the seat frame. It will have all new fenders, doors, hinges, bed, tailgate rubber seals, and front and rear bumpers and all associated hardware.
 
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454cid

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If I keep it at 4" what size shocks (or part # if you know) if I lower it to say 3" what size do I need?[

You don't normally buy shocks by "size", you look to see what's listed for the truck. Most of what's offered will assume stock height, but you'll find some that will specify that they are for a lifted truck and will provide an inch measurement over stock height.

The only original parts will be the frame and the cab shell and the seat frame. It will have all new fenders, doors, hinges, bed, tailgate rubber seals, and front and rear bumpers and all associated hardware.

Use the good of what you have... if the truck is that far gone, get a truck that's in better shape. Doing what you want to do, your truck will be 3/4s imported aftermarket.
 

Wlfman

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I am getting a factory bed and tailgate. If I can find good factory parts for the rest of the body I will use them, but living in MI it's hard to find any body parts that aren't completely eaten by rust. The bed is actually being sent up from southern Indiana as I couldn't find one in decent shape up here. All suspension parts will be Moog or the best I can find. Being that it's almost 30 years old, there aren't a lot of options for new old stock at this point. I will find the best parts I can and go from there. Thanks for the help.
 

MSCustoms

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Check your front diff first. I have an old trailmaster where the bottom main diff mount attaches to the drop down bracket for the lower control arms and the top has spacers from the factory location. My new lift will cut the diff mounts off and add a bracket to the diff itself
 

1989GMCSIERRA

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Some of the aftermarket lifts on the GMT400 chassis cut off the factory suspension mounts so it can never be brought back to factory height.

The shocks are bought by length guide. Most 4x4 shops will have suggestions. If the manufacturer is around they will tell you or send you the full installation instructions.

You can buy quality replacement parts. Dana Spicer makes good ball joints.
 
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