Improving the steering stability 1997 4X4 2 dr Tahoe

[Jim b]

Hello, I have a 1997 2Dr Tahoe 4X4. It was stock with 160K miles except for some aftermarket wheels when i purchased it.
It was horrible to drive due to serious wandering. I replaced the aftermarket wheels (wrong offset) with some 17" Gm alloys. This helped considerably. I replaced all ball joints, a-arm bushings, tie-rods, drag links etc. Not much improvement.
The steering box does not have any obvious slop. Since this initial effort I have done the Cumin's swap. The swap did not make it better or worse. It's not terrible at this point but requires more driver input than my Dodge ram by 5X.

Are there improved caster and camber settings that will improve the steering stability? Has anyone been able to make their Tahoe drive unbelievably well?
Thanks!
Jim B

 

[Joseph Garcia]

"Has anyone been able to make their Tahoe drive unbelievably well?" This is rather subjective regarding 'unbelievably well'.

You 'should' be able to have a Tahoe that you are happy with. I had a '97 Yukon that I believed drove very well, for a truck.

What tires are you using?

@MO VietVet has had Tahoes and currently has one that he believes drives well. He may be able to provide some input.

 

[east302]

Yeah, handling is subjective depending on what you’re comparing it to. The short wheelbase doesn’t help, my 98 two-door is jittery and would probably benefit having a rear sway bar like the four doors. I also have two 98 extended cab K1500s and the longer wheelbase makes a considerable difference.

They all transmit even minor pavement defects straight into the cab, regardless. Nature of the beast.

My Tahoe’s handling is not unlike a 93 Bronco that I had but both are miles behind anything made in the last twenty years. I think it’s just inherent in the short wheelbase and technology - probably similar to an older Wrangler.

If you are having to constantly correct the steering then that is not normal and could be an alignment issue as you mentioned. That’s assuming that you don’t have really wide tires that are tracking in the two road lane grooves or whatever they’re called.

Is your suspension stock? Lifted or torsion bars cranked?

Mine is leveled (1-1.5” crank) on 285s and handles pretty well. It tracks straight but the back likes to twitch if you get overzealous with it. It doesn’t wander and I don’t have to constantly correct the steering. It’s at home on flat interstates and reminds you to slow down on the twisties.

I’ve always had trouble finding someone that can do an alignment right the first time, but a place other than a chain tire shop may be worth consulting. Look for an older shop where they still allow smoking in the lobby. You know what I mean

Besides the steering gearbox (is there any lag between the steering shaft and pitman arm turning?) and suspension components that you have already addressed, take a look at the rag joint on the steering shaft just in front of the connection to the gearbox. Some movement and flex is normal, but the fibers shouldn’t move and twist like a bunch of wet paper towels.

If you go the gearbox route, there were two used: one for 96 and under, one for 97+ which used the EVO system on the power steering pump. I have a pre-96 box on my 98 and it was noticeably stiffer - just shy of you wondering if the power steering is out. I like it a lot. I have the post-97 gearboxes on my 98 pickups and they are looser but still track straight without correction. They’re more akin to an old Ford or Buick, just sort of vague but not enough to make you worry or have to think too much about it.

Skip the parts store remans and even AC Delco on these Saginaw boxes. They’re too much of a pain to install to risk buying one and having to remove it the same day. Been there, got the t-shirt. Go with a BlueTop or Redhead reman as they are much more likely to be good right out of the box.

 

[Joseph Garcia]

Yeah, handling is subjective depending on what you’re comparing it to. The short wheelbase doesn’t help, my 98 two-door is jittery and would probably benefit having a rear sway bar like the four doors. I also have two 98 extended cab K1500s and the longer wheelbase makes a considerable difference.

They all transmit even minor pavement defects straight into the cab, regardless. Nature of the beast.

My Tahoe’s handling is not unlike a 93 Bronco that I had but both are miles behind anything made in the last twenty years. I think it’s just inherent in the short wheelbase and technology - probably similar to an older Wrangler.

If you are having to constantly correct the steering then that is not normal and could be an alignment issue as you mentioned. That’s assuming that you don’t have really wide tires that are tracking in the two road lane grooves or whatever they’re called.

Is your suspension stock? Lifted or torsion bars cranked?

Mine is leveled (1-1.5” crank) on 285s and handles pretty well. It tracks straight but the back likes to twitch if you get overzealous with it. It doesn’t wander and I don’t have to constantly correct the steering. It’s at home on flat interstates and reminds you to slow down on the twisties.

I’ve always had trouble finding someone that can do an alignment right the first time, but a place other than a chain tire shop may be worth consulting. Look for an older shop where they still allow smoking in the lobby. You know what I mean

Besides the steering gearbox (is there any lag between the steering shaft and pitman arm turning?) and suspension components that you have already addressed, take a look at the rag joint on the steering shaft just in front of the connection to the gearbox. Some movement and flex is normal, but the fibers shouldn’t move and twist like a bunch of wet paper towels.

If you go the gearbox route, there were two used: one for 96 and under, one for 97+ which used the EVO system on the power steering pump. I have a pre-96 box on my 98 and it was noticeably stiffer - just shy of you wondering if the power steering is out. I like it a lot. I have the post-97 gearboxes on my 98 pickups and they are looser but still track straight without correction. They’re more akin to an old Ford or Buick, just sort of vague but not enough to make you worry or have to think too much about it.

Skip the parts store remans and even AC Delco on these Saginaw boxes. They’re too much of a pain to install to risk buying one and having to remove it the same day. Been there, got the t-shirt. Go with a BlueTop or Redhead reman as they are much more likely to be good right out of the box.

Thank you for reminding me about the EVO system. I forgot about that PIA and failed feature. For my 97 Yukon (RIP), I disabled this system, when it failed.

To the OP: Find out if you have an EVO system on your power steering pump. If you do, get the disable kit from GM, as a failed EVO system is not only unpleasant to drive, but it also a safety hazard after failure.

 

[exp500]

Don't forget to change Jounce Bumpers in front.
Wheel alignment - Try to get 3+ caster, 0 camber, 1/16 in toe. Sometimes hard to get 1.5 caster.
Get rid of EVO, dangerous. Use 96 pressure line from pump. Remove EVO valve from pump, Leave EVO valve plugged in but tywraped securely to block. (no codes this way). Most aftermarket p/s pumps come with a bypass tube. Cannot buy them seperately except thru GM. Using 96 pressure line eliminates extra joints to leak. And you were going to change it anyway.
Post your alignment sheet as well as any more questions.

 

[Jim b]

Thank you very much for the replies. I get it regarding the short wheelbase and relatively high profile. My friend has a 2001 4 door and it has always driven very nice.

My 305's are a Chinese all terrain on stock offset OEM wheels. It drives better with these than anything that I have had on it. Grantet the vehicle would probably be happier with 265's. I had to crank up the torsion bars when I installed the Cummins to level it up. But the handling before and after the swap is similar. I had eyes on the steering shaft but will give the rag joint a closer inspection or simply replace it. The Red head box is probably just a worthwhile upgrade. Also the rear sway bar and maybe a set of Bilstien 5400 series shocks.
On my ram there is a kit that replaces the pitman arm nut with an extended one then a cross-member that ties both frame rails together engages that nut with a bearing to stabilize the steering output shaft. It made a night and day improvement on the ram when it was still a young rig with 20 K miles. I have not ran across anything like that for the Tahoe and have considered fabricating something.

I disabled the EVO system when I did the swap as I used a standard cummins/Saginaw PS pump.
I will go with the caster and toe settings on the next alignment. My dune buggy/desert car really responded to adding positive caster. I like to run as little toe as I can get away with for efficiency (rolling resistance) but not at the expense of drive ability.
I won't get to working on it until later this spring as we winter in Baja.

Thanks again,
Jim B

 

[drakon543]

so im assuming your misspelled cummins and you have a diesels now or there's something im not aware of. anyway you haven't mentioned doing the idler or pitman arms. you suggested the steering box seems ok but didn't mention those. bigger taller tires definitely wont help as your adding more tire to flex around. also you would be suprised how much good tires feel totally different than cheaper knock offs. my 97 was on 17s dont remember the offset but they were just starting to stick out with 265 70 17s. it handled amazingly well even with the alignment off. you have more weight (i believe not sure on the weight of the engine) and you cranked the keys which makes the front stiffer regardless of the weight your putting on it. it sounds like you might still have a weak component paired with your modifications that are counteracting your desired feel.

 

[drakon543]

according to varying sources your 5.7 vortec was about 500 pounds that cummins supposedly weights 1100

 

[Jim b]

The 4BT is about 750lbs (6BT is around 1100), the NV4500 about 220. I probably gained 350-450lbs. I have had it over the scales and I seem to remember 5800 but before I get it aligned next time I will weigh both axles.
Is the implication that I would have an unbalanced spring rate carrying the heavier load between the front and rear? I did also replace the drag link and idler (not sure of terminology) when I refurbed the front end before the swap. The OEM parts that I pulled off were somewhat worn and the rubber seals were going away but as I stated swapping out the front end parts made a minor improvement. I think that the steering box is probably more worn than I suspected. The feeling that I get from from the replies is that it should drive pretty well. This is encouraging! Since the chassis components are similar to a 1/2 ton PU my modest load increase seems like it should be within comfortable limits for the chassis.
(Editorial)......
Chinese tires are not necessarily bad tires. I am running load range F's on my ram. When I purchased them a few years ago load range F's in my size were very hard to find in any brand. I needed the load range F because my rear axle load was putting the load range E tires over their limit. I haul a slide in camper and pull a big enclosed trailer, typical CGVW is 22k it drives great and is not fussy at all. I have been running them 3 seasons and they still look nearly new. I am using them on my 3 axle equipment trailer that I haul a Case 580 on. Zero problems. Trailer duty is rough duty when you make a turn the loads that those tires endure are ugly. I am running them on my Monaco 36ft class A no issues at all. It drives just the same as with the previous Good Years. Any tire mfg can have issues. It takes a tough tire to survive at rated load full time. Check out the tire failures of name brand tires on class A motor homes. It is an epidemic. So bad that they recommend that you swap them out every 4 years regardless of mileage. When I spent a few weeks in the Shanghai area in 2012 the roads were full of all types of vehicles. Lots of trucks obviously loaded heavier than would be allowed in the US. The roads were not covered with tire carcasses or trucks with flat tires.

 

[exp500]

I always liked the 4BT swap, NV4500 is a bonus as most use TH400. Long ago I had a short C40 with a 4-53 and it was fun to drive.

 

[drakon543]

The 4BT is about 750lbs (6BT is around 1100), the NV4500 about 220. I probably gained 350-450lbs. I have had it over the scales and I seem to remember 5800 but before I get it aligned next time I will weigh both axles.
Is the implication that I would have an unbalanced spring rate carrying the heavier load between the front and rear? I did also replace the drag link and idler (not sure of terminology) when I refurbed the front end before the swap. The OEM parts that I pulled off were somewhat worn and the rubber seals were going away but as I stated swapping out the front end parts made a minor improvement. I think that the steering box is probably more worn than I suspected. The feeling that I get from from the replies is that it should drive pretty well. This is encouraging! Since the chassis components are similar to a 1/2 ton PU my modest load increase seems like it should be within comfortable limits for the chassis.
(Editorial)......
Chinese tires are not necessarily bad tires. I am running load range F's on my ram. When I purchased them a few years ago load range F's in my size were very hard to find in any brand. I needed the load range F because my rear axle load was putting the load range E tires over their limit. I haul a slide in camper and pull a big enclosed trailer, typical CGVW is 22k it drives great and is not fussy at all. I have been running them 3 seasons and they still look nearly new. I am using them on my 3 axle equipment trailer that I haul a Case 580 on. Zero problems. Trailer duty is rough duty when you make a turn the loads that those tires endure are ugly. I am running them on my Monaco 36ft class A no issues at all. It drives just the same as with the previous Good Years. Any tire mfg can have issues. It takes a tough tire to survive at rated load full time. Check out the tire failures of name brand tires on class A motor homes. It is an epidemic. So bad that they recommend that you swap them out every 4 years regardless of mileage. When I spent a few weeks in the Shanghai area in 2012 the roads were full of all types of vehicles. Lots of trucks obviously loaded heavier than would be allowed in the US. The roads were not covered with tire carcasses or trucks with flat tires.

you only suggested chinese tires so i can only assume they were the cheapest thing you can find testing for fitment or something. with torsion bars its basically like having a single rate coil springs your basically riding around with them almost bottomed out with the keys cranked up. those bars only have so much spring twist in them. anyway as im still unsure of the capabilities of the tires im just going to assume they super squishy sidewalls with basically a super stiff suspension spring rate. the 4bt is about 750lbs with just the engine and oil. do you only have the alternator and ps on it for accessories? they don't weigh much just by themselves. so your definitely lighter up front than i thought maybe a bit heavier than you think tho according to what im reading. hmmm what are you running for shocks up front? the drag link is your steering cross bar the pitman arm is the z ish shaped arm off the steering gearbox to the passenger side there is another up there looks very similar called the idler arm. when i had my 97 i used to always run a mid load range tire dont remember exactly what load range it was but it could handle all the seats down fully loaded and a 16ft trailer fully loaded. my current assumption is your suspension is very stiff due to the extra weight and stiffness of the torsion bars paired with tires with very large sidewalls trying to flex and bounce and possible need for a firmer shocks to handle those points. maybe a mild lift and backing off on the torsion bars. sounds like your going all in anyway why not just go all the way and do a solid axle swap.

 

[Jim b]

I always liked the 4BT swap, NV4500 is a bonus as most use TH400. Long ago I had a short C40 with a 4-53 and it was fun to drive.

What year was the C40? Sounds nice. How did it perform?
On the highway the slightly cranked up 4B performs as good or better than the 350 did. I love pulling a 6% grade in 5th at 5000ft!
I am an old guy and still love manual transmissions. I should qualify that with overdrive manual transmissions! My first was in a 67 opel Kadet that I swapped a 225 buick V6 with a 3 speed with OD behind it. 3.08 gears. 3100 at 100. 35mpg if you kept it at 80 or less. Even though the 225 did not make huge power it did well in a 1800lb car. Surprised a few folks.

 

[Jim b]

you only suggested chinese tires so i can only assume they were the cheapest thing you can find testing for fitment or something. with torsion bars its basically like having a single rate coil springs your basically riding around with them almost bottomed out with the keys cranked up. those bars only have so much spring twist in them. anyway as im still unsure of the capabilities of the tires im just going to assume they super squishy sidewalls with basically a super stiff suspension spring rate. the 4bt is about 750lbs with just the engine and oil. do you only have the alternator and ps on it for accessories? they don't weigh much just by themselves. so your definitely lighter up front than i thought maybe a bit heavier than you think tho according to what im reading. hmmm what are you running for shocks up front? the drag link is your steering cross bar the pitman arm is the z ish shaped arm off the steering gearbox to the passenger side there is another up there looks very similar called the idler arm. when i had my 97 i used to always run a mid load range tire dont remember exactly what load range it was but it could handle all the seats down fully loaded and a 16ft trailer fully loaded. my current assumption is your suspension is very stiff due to the extra weight and stiffness of the torsion bars paired with tires with very large sidewalls trying to flex and bounce and possible need for a firmer shocks to handle those points. maybe a mild lift and backing off on the torsion bars. sounds like your going all in anyway why not just go all the way and do a solid axle swap.

The engine has a full compliment of functioning accessories. Actually the tires are load range D. Not the cheapest but had the profile that I wanted. THe load capacity is significantly greater than the load. No the sidewalls are not super squishy, It in no way rides harshly compared to my 2500 ram quad cab, nor does it wallow around like a 1972 LTD. The suspension is rather compliant and well behaved. The shocks are KYB's but not new. It does not have uncontrolled damping. Again the handling is better than when the vehicle was in stock form with 160K on it. I am pretty confident from other replies that replacing the steering box with a stiffer unit and getting the caster dialed in will make me happy. Contrary to what some true believers think you can successfully modify a vehicle from its "compromised to the maximum factory configuration" without causing issues. I have over 40k miles on the rig since the conversion and the only complaint is the wander issue. That is the only major complaint that carried over after the mods. Prior to that it was constantly shifting, unable to hold OD on minor grades, horrible fuel efficiency. I use this rig pretty hard. I pull my 27' pontoon boat up and down 8-9% grades many times a season. This is not on high speed roads. These roads are very crooked and require slow speeds and careful driving. It is equally happy running 65 with a utility trailer. While it is not a HD tow vehicle the short wheelbase and low range (with a switch on the xfer case lever to disable the front axle) make it ideal for maneuvering in tight spaces. It will pull the pontoon boat out of the lake at an idle. Just let the clutch out and it goes. So much more satisfying that the vortec. jim

 

[exp500]

C40 was a 67 dump, small single axle 5x3 trans. Like a rowboat! Had a 427 powered truck around same time that had more power but was very thirsty!

 

[drakon543]

The engine has a full compliment of functioning accessories. Actually the tires are load range D. Not the cheapest but had the profile that I wanted. THe load capacity is significantly greater than the load. No the sidewalls are not super squishy, It in no way rides harshly compared to my 2500 ram quad cab, nor does it wallow around like a 1972 LTD. The suspension is rather compliant and well behaved. The shocks are KYB's but not new. It does not have uncontrolled damping. Again the handling is better than when the vehicle was in stock form with 160K on it. I am pretty confident from other replies that replacing the steering box with a stiffer unit and getting the caster dialed in will make me happy. Contrary to what some true believers think you can successfully modify a vehicle from its "compromised to the maximum factory configuration" without causing issues. I have over 40k miles on the rig since the conversion and the only complaint is the wander issue. That is the only major complaint that carried over after the mods. Prior to that it was constantly shifting, unable to hold OD on minor grades, horrible fuel efficiency. I use this rig pretty hard. I pull my 27' pontoon boat up and down 8-9% grades many times a season. This is not on high speed roads. These roads are very crooked and require slow speeds and careful driving. It is equally happy running 65 with a utility trailer. While it is not a HD tow vehicle the short wheelbase and low range (with a switch on the xfer case lever to disable the front axle) make it ideal for maneuvering in tight spaces. It will pull the pontoon boat out of the lake at an idle. Just let the clutch out and it goes. So much more satisfying that the vortec. jim

ya i modify just about everything i own to fit my desire. wasn't trying to shoot any other suggestions down just going with what i know is a potential from the modifications you have already done. i haven't ridden in your truck so i cant really feel what you feel so my suggestions can definitely be contradictory to what your actually feeling. ive ridden in vehicles with extra weight upfront with a similar setup and my suggestions would have fit that vehicle. if the handling is there and its just not crisp enough for you then you would probably be heading in the correct direction with the other suggestions.

 

[Jim b]

Just wanted to update this thread. I finally had a chance to look into my wandering problem. Based on issues that I had with my desert buggy that I solved by adding positive caster I decided to try that on the Tahoe. I set it to nearly Max available with the common upper control arm cam system. I have not measured it. I then reset the toe in to slightly more than zero. WOW the thing drives like it's on rails. I am so happy with the improvement. It feels like I could get away with zero toe in but for now I will leave a bit in there. My coasting test indicates that it is rolling super easy as is.

So if you have wandering issues and you can't find any worn or bad components try more + caster.
Best Regards,
Jim

 

[exp500]

Please edit the title of post, add "SOLVED" . Thanks, Makes finding a fix easier.

 

[Jim b]

Please edit the title of post, add "SOLVED" . Thanks, Makes finding a fix easier.

I would love to do that. Can I edit the original title of the post? If so how to access it? Thanks! Jim B