jpeterferrell

Also, I was curious as to what transmission temperatures I should be looking for on a trip like this. Just tooling around town, with the vehicle more or less empty, and temps between 50 and 80, based on the gauge on the dash the transmission seems to generally be between 120 and 175. When it's hotter out here and I'm on it more, it gets in the 175-200 area. The fluid is perfectly fine, I know it's flowing through the cooler, but it does have the 215k on it. The one thing I haven't done is pull the pan and swap the filter - I mostly just didn't want to mess with that if the fluid looked good and temperatures stayed reasonable. Anything to be concerned about there?

That's a very good point. Turns out it's quite a bit less than I thought it would be (most quotes are ~$1k). Now, the question is if I decide not to do the towing adventure, do I ship the Suburban and drive the ID.4 (longer trip, but $0 in gas), or ship the ID.4 and drive the Suburban with just me and the dog in it...

I have posted a few times here before about my project of restoring a 2002 Suburban 2500, 8.1L, 4x4 LT. The truck has 215k but is in great shape. I recently rebuilt the entire front end, and replaced every component in the power steering/braking system (pump, hydro boost, steering gear, lines, etc). I replaced all four shocks with Bilstein 5100s a year or so ago. I have been daily driving the vehicle 2-3 days a week as a kind of shake down, but it's getting time to take my first adventure in towing, and I need some advice. The Suburban has the factory hitch and 7-plug wiring port, and the previous owner wired in a trailer brake controller. I've never towed anything beyond pulling a ~3k pound sedan on a 2-wheel dolly behind a U-Haul truck in college. This summer, I need to tow my wife's Volkswagen ID.4 (curb weight is ~5500 pounds) on a car hauler from Colorado to Virginia as a part of a move. I won't have any real opportunity to do serious towing prior to that. To prepare I bought a good weight distributing hitch (a Weigh-Safe rated for up to 15k), and I plan on buying a car hauler here in Colorado and at least practice getting it hooked up before the big day comes. I know I'll need to buy some straps to secure the ID.4 to the car hauler (I'll have to use the kind that goes around the tires, since the ID.4 doesn't really have traditional axles). I have done every bit of maintenance one can do - every fluid change, swapped a gallon of transmission fluid every time I oil change (I've cycled ~6 gallons through it, it now comes out bright cherry red every time I do it). Is there anything else I need to be doing to the truck to get it ready for this trip? Anything I possibly can do before I have the car hauler and load up the ID.4? Anything I should expect on the trip itself? I am really new to towing anything (much less ~7k pounds of combined vehicle and hauler), and will really only get one shot at it. Any advice you all can give would be very helpful!

Shop replaced the pump last week with a PSC upgraded unit - I’ll be picking it up this afternoon and we’ll see where it’s at!

UPDATE: I've done some experimenting, bled the system several more times, flushed the fluid, and think I've got it diagnosed. I get steering and braking as I would expect in virtually every condition, with the sole exception of while stopped, with the brake applied. In that situation, I have ZERO steering assist. I can't turn the wheel at all (at least not without extreme force applied). When I try, the power steering pump complains, groans, whines. If I put the vehicle in park, take my foot off the brake, but remain stationary, I get power assist back - I can turn the wheel stop to stop. Lift off the brakes, put even the slightest bit of throttle on, and it's even less of a problem - I get steering assist, enough for me to generally navigate around no problem (although not as much boost as I would expect). In all conditions, the assist seems not quite like what I would normally expect for a truck like this, that and my "return to center" after turning isn't nearly as strong. So, I still suspect I have a power steering pump that just can't keep up with a new hydro boost and a new power steering gear. I'm going to have a shop replace the pump next week and we'll see where we are!

My fault - the vehicle has hydroboost stock. I just upgraded the unit itself to an upgraded part from a 2011. The stock hose routing requires it going through the hydroboost.

That's exactly right - I think without some kind of specialty tool (basically a bypass block), which I'm not even sure actually exists, there's no way to just bypass the hydro boost altogether. I really don't want to just throw parts at this thing, but it also seems there may not be a way to easily diagnose it for a shade tree type like myself. I'm going to double-check all the fittings this weekend, maybe do one more bleed (maybe even flush from the hydro boost?) and see where I'm at. After that, I may have to resort to professional help!

This is definitely possible. The pump DOES look to be original, before I started swapping parts I did a full flush, and the fluid coming out was horrid looking (straight black). The hydroboost is definitely functioning perfectly fine, and the loop does go pump --> hydroboost --> steering gear. I can absolutely see the pump just not supplying enough overall pressure to work both the upgraded hydroboost and the new steering gearbox, particularly when I have much heavier inner/outer tie rods/pitman arm/idler arm bolted up. I was going to buy the PSC SP1404 pump as my replacement...anyone have any experience with it? Should I go with that or a stock AC DELCO replacement...? Cost is...more or less the same between the two, but the PSC looks like an upgraded unit..

Sorry, I should have been more clear. I used a hydro boost from a 2011 - it's a well known upgrade part over the 2002-2010 models. The hydro boost works great - bolted right up, fittings went in perfect, brakes way better than before. For the same reason, I don't suspect the pump (which I haven't changed at all), since if the pump was bad it seems like they hydro boost wouldn't function either. I'm going to try bleeding one more time, then I'll contact BlueTop. Seems weird that the gearbox would "work" perfectly fine, not make noise, etc, but just have no power assist? I did retrace the lines to make sure I hooked them up right, checked for leaks, checked the condition of the fluid, and all of that seemed good. I'm really hoping I'm just working out some larger bubbles that had found their way into the gearbox and sat there for awhile...

Hey everyone! I'm brand new to this forum, and brand new to the GM world, but have run into an issue with my 2002 Suburban 2500 (8.1L) that has me completely stumped. First, a bit of background: I have been slowly doing a complete front-end rebuild on the truck over the course of the last year or so. I had 215k on the clock, and while the rig was very well maintained generally, it was in pretty dire need of a suspension and steering refresh. So, here's what I've done already: 1) Kryptonite UCAs 2) Kryptonite LBJs 3) MOOG lower ball joint bushings 4) Kryptonite inner and outer tie rod ends 5) Bilstein 5100 shocks (front and rear) 6) Kryptonite Torsion key leveling kit 7) Kryptonite Death Grip Pitman Arm (8) 2011+ AC DELCO Hydrobooster 9) New AC Delco Brake master cylinder and reservoir Then, I replaced the power steering gearbox with a BlueTop unit. Everything seemed to work fine initially, it took me awhile to bleed the system, but I am positive I have all the air out of it now. I also replaced the two high pressure power steering lines while I was at it (both were clearly slowly leaking/weeping). Now, after having everything completely aligned again, I've run into what seems to me to be a bizarre problem. The P/S pump doesn't whine any more than normal. The Hydroboost works strong (very strong after the 2011 upgrade). BUT, when sitting still, I have virtually no power steering assist. I can't turn the wheel left to right at all. Start to move (really, even the slightest bit) and it frees up and I can go along. At first I thought I must have gotten a bad steering gearbox - but this assist problem is extremely intermittent. Sometimes, I can turn the wheel stop to stop while sitting still, no problem. Other times, I can't do it at all. The hydroboost works perfectly fine, and perfectly consistently. The pump doesn't sound like it's whining. The fluid level is perfect. Anyone have any idea what could be causing this, before I go throwing more parts at it...?