• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Can you put a 6L90E into a 4L80E '98 K2500 Suburban 6.5TD?

Gear Vendor unit not really an option on the K2500. I'd have six grand into it after divorcing the transfer case from the transmission, putting the GV in between, and then making all new front and rear drive shafts to maintain 4WD, or else mount it behind the transfer case and use it only in 2WD and still have to make a new drive shaft for the rear. 3.42's in the front and rear diffs would only help a little bit from my 3.73's, I don't want to go to 33" or 35" tires and a lift because of the air resistance factor. 3.42's with an ~ 0.62 OD would be ideal RPMs at 75-80MPH. If they made a 3.21 ring and pinion for the front 9.25" IFS diff like they do for the 10.5" 14 bolt rear diff, problem solved using the 4L80E, but they don't. ZF6 may be the route to go. A stick shift 'Burb would be cool.
 
jrsavoie said:
I suggested that a Manual transmission in the Suburban would be nice - especially because I found a cheap fairly low mileage donor truck - The wife informed me that I as way wrong on the subject
Click to expand...

See, you're missing a great bonding opportunity teaching her to drive a stick shift!
 
ZF6 won't do diddle for getting taller gearing, all the gears are splitting below 1:1 5th and 6th is .72:1, barely taller than the 4L80E's .75:1. Even swapping out to 3.42's F&R from 3.73's, the RPM difference in OD is still negligible. I need to drop RPM's down to 1800-1900 @ 80 MPH in OD. for ultimate MPG's and cruising range.
 
as far as options to get lower than .72 overdrive your options are very limited. A ranger or gear vendors overdrive add on is about your cheapest option, unless you find a custom trans with the overdrive ratios you want that will survive the torque of your motor.
 
Michaeljp86 said:
What about running a higher gear in the differential?
Click to expand...

With my 'Burb, that's differentialS. Right now the K2500 has the stock 3.73's F/R. The 3.42's don't give that much of a drop in RPM's at 75-80mph cruising on the Interstate to get me into the 1800-1900 RPM range I want to be in at those speeds. 3.21 does, but it is available only for the 10.5" 14 bolt rear, not for the 9.25" IFS front differential and obviously you don't run different ratios front and rear and expect to keep the transfer case in one piece for more than a few minutes in 4WD. No, I do not want to run wider/taller tires to get the RPM's down, as then there's bodylifts, increased air resistance, etc that defeats the purpose of gearing taller. I'm running 245/75R-16E right now, and wouldn't want to go any taller/wider than maybe 265/75R-17E without having to lift the body for tire/wheel clearance, but then I'm looking at having to buy five new rims and tires to do that on top of regearing the diffs. But then the 'Burb is still sitting up a couple of inches higher, and that much more in the wind, even without lifting to get the really tall tires on to drop the RPM's down.
 
Michaeljp86 said:
I wonder if you could add one of these overdrive kits to a 4l80e?

http://www.gearvendors.com/cg2wd3s.html
Click to expand...

Yes, one can, but see farther up above as to why I wasn't thrilled with that solution, either it goes after the transfer case so that I have double OD only in 2WD with a cut out switch of some sort so that if put in 4WD accidentally with the GV still engaged, it will automatically cut out and also so that the GV can't be engaged if already in 4WD, or I wind up divorcing the transfer case and putting the GV in between so that it works in both 2 and 4WD with all the additional fabbing and $$$ on the drivetrain.
 
With the gearvendor how often would you ever be running more than 65 in 4 wheel drive? The stock 241 transfer case doesn't have a differential in it, and it would eat up a chain in short order if you ran it for to long on dry roads. Secondly, I would NEVER put a HEAR VENDOR into a bURB. I'm sure they will tell you it works fine, but I can attest it DOESN'T! I put one into mine, and it created the WORST driveline harmonics I have ever felt in my life. At 45-60 my BURB would shake so bad you couldn't see teh road in front of you. It took my rearview mirror off the windshield in less than 2 minutes it shook so violently. I spent alot of time working on it, and after alot of work I came to the conclusion that the shortened driveshaft, combined with my BANKS exhaust, and the extra leverage of drivetrain hanging back behind the trans mount created a harmonic of EPIC proportions. you could watch it on jackstands when you brought it up to 55 the whole trans, transfer case, and gear vendor unit would move almost an inch in an eliptical circle which would in turn start the frame and exhaust to resonating and vibrating, and before you knew it it was about ready to shake it apart.

And taller tires will help, wider tires will hurt. Put a set of 235/85/16's on it if your after the effect of higher gearing.
 
ferm, was this on the duramax?

do you think a 2wd burb and a gearvendors would get along OK?

btw, I heard those Hear Vendor's dont work that good anyhow. ;) :D I am betting the Gear Vendors may work better.

to the OP, ferm is onto something with the rubber, for the height, LT235/85R16 has the smallest contact patch of anything else similar in height. make up for the height difference by de-cranking the t-bars and putting an airdam on. btw, I went through GM, and the air dam with tow hook holes is cheaper than the plain one, and IIRC, with tax and all, I think it was 55 bucks. I also saw some 255/85R16s on a K2500HD, and it was very tight on the fender, and probably rubbed the frame, but they sit even higher.
 
GM Guy said:
ferm, was this on the duramax?

do you think a 2wd burb and a gearvendors would get along OK?

btw, I heard those Hear Vendor's dont work that good anyhow. ;) :D I am betting the Gear Vendors may work better.

to the OP, ferm is onto something with the rubber, for the height, LT235/85R16 has the smallest contact patch of anything else similar in height. make up for the height difference by de-cranking the t-bars and putting an airdam on. btw, I went through GM, and the air dam with tow hook holes is cheaper than the plain one, and IIRC, with tax and all, I think it was 55 bucks. I also saw some 255/85R16s on a K2500HD, and it was very tight on the fender, and probably rubbed the frame, but they sit even higher.
Click to expand...

It was when I first bought it back in 04 when I tried the GEAR vendor out, so it was definately a 6.5. For a 2WD it would probably be fine. The Gear vendor was actually why I joined DP and another forum back in the day. The owner had been dodging my phone calls for 3 months because I wanted him to honor there money back guarantee, and he didn't want to pay it. It's funny how he knew exactly WHO to call when people started calling them up asking about the forum posts.
 
Husker6.5 said:
With my 'Burb, that's differentialS. Right now the K2500 has the stock 3.73's F/R. The 3.42's don't give that much of a drop in RPM's at 75-80mph cruising on the Interstate to get me into the 1800-1900 RPM range I want to be in at those speeds. 3.21 does, but it is available only for the 10.5" 14 bolt rear, not for the 9.25" IFS front differential and obviously you don't run different ratios front and rear and expect to keep the transfer case in one piece for more than a few minutes in 4WD. No, I do not want to run wider/taller tires to get the RPM's down, as then there's bodylifts, increased air resistance, etc that defeats the purpose of gearing taller. I'm running 245/75R-16E right now, and wouldn't want to go any taller/wider than maybe 265/75R-17E without having to lift the body for tire/wheel clearance, but then I'm looking at having to buy five new rims and tires to do that on top of regearing the diffs. But then the 'Burb is still sitting up a couple of inches higher, and that much more in the wind, even without lifting to get the really tall tires on to drop the RPM's down.
Click to expand...

You making me think about putting the 3:21 since my rig is a 2wd. My truck sucks fuel at highway speeds. I need to drop the RPM like you mentioned. I still have 2 years in college which is about 15 hwy miles one way. And we all know fuel prices have no where to go but up.
 
THEFERMANATOR said:
With the gearvendor how often would you ever be running more than 65 in 4 wheel drive? The stock 241 transfer case doesn't have a differential in it, and it would eat up a chain in short order if you ran it for to long on dry roads. Secondly, I would NEVER put a HEAR VENDOR into a bURB. I'm sure they will tell you it works fine, but I can attest it DOESN'T! I put one into mine, and it created the WORST driveline harmonics I have ever felt in my life. At 45-60 my BURB would shake so bad you couldn't see teh road in front of you. It took my rearview mirror off the windshield in less than 2 minutes it shook so violently. I spent alot of time working on it, and after alot of work I came to the conclusion that the shortened driveshaft, combined with my BANKS exhaust, and the extra leverage of drivetrain hanging back behind the trans mount created a harmonic of EPIC proportions. you could watch it on jackstands when you brought it up to 55 the whole trans, transfer case, and gear vendor unit would move almost an inch in an eliptical circle which would in turn start the frame and exhaust to resonating and vibrating, and before you knew it it was about ready to shake it apart.

And taller tires will help, wider tires will hurt. Put a set of 235/85/16's on it if your after the effect of higher gearing.
Click to expand...

Well, New Year's Eve 2010 (Dec 31, 2009) I ran I-80 from Lincoln to just past Des Moines in a sleet/ice storm in 4WD at between 45-75 MPH. We get real weather out here that necessitates 4WD on the highway at highway speeds. You sure your drive shaft was balanced, just asking? Also, what about a second cross member to support the tail of the GV? Why wouldn't it work on a Suburban, since the wheel base is the same as a RCLB P/U and those run with no problem? I do think what I'm going to wind up with is going to 3.42's F/R for the ring and pinion and taller tires, probably 33" in diameter. If I can land between 1800-1900 RPM @ 75-80MPH I'll be happy.
 
GM Guy said:
putting an airdam on. btw, I went through GM, and the air dam with tow hook holes is cheaper than the plain one, and IIRC, with tax and all, I think it was 55 bucks. I also saw some 255/85R16s on a K2500HD, and it was very tight on the fender, and probably rubbed the frame, but they sit even higher.
Click to expand...

As a fully optioned LT, it has the air dam with the tow hook. BTW, through LMC Truck, either air dam is $29.95. I've seen them as low as $22 on eBay, too. I avoid the stealership as much as possible. For instance, the little light bulbs used to illuminate the power window and door lock buttons in the Driver's arm rest? Stealership's parts book doesn't even list them as a replacement part for when they do eventually burn out, wanted to sell me a whole new switch assembly with the lamps in it for $138. LMC has the bulbs at $12 ea. Not exactly cheap, but when you consider the originals lasted for 11 years and 200,000 miles. . .
 
Ferm I'm very curious about the vibration issue you had with the gear vendors. Have a friend who had one in a 90's suburban with the 350, 4x4, worked just fine. He added a second crossmember and had a new driveshaft to eliminate the carrier bearing.
 
Husker6.5 said:
Well, New Year's Eve 2010 (Dec 31, 2009) I ran I-80 from Lincoln to just past Des Moines in a sleet/ice storm in 4WD at between 45-75 MPH. We get real weather out here that necessitates 4WD on the highway at highway speeds. You sure your drive shaft was balanced, just asking? Also, what about a second cross member to support the tail of the GV? Why wouldn't it work on a Suburban, since the wheel base is the same as a RCLB P/U and those run with no problem? I do think what I'm going to wind up with is going to 3.42's F/R for the ring and pinion and taller tires, probably 33" in diameter. If I can land between 1800-1900 RPM @ 75-80MPH I'll be happy.
Click to expand...

Believe me, I wished it had been just a driveshaft problem. I even went to the extreme of having different diameter shafts built for it to see if it was a critical speed vibration matching a vehicle harmonic and causing it. The icing on the cake was when I put it in 4 wheel drive and drove it without a rear driveshaft and STILL had a vibration in it. I'm not new to finding vibrations, and this was just one of those scenarios that I never could narrow down to any one factor. As for why a BURB does it and a truck doesn't, I believe it is along the same lines as why is one exhaust quiet in a truck but loud and obnoxous in a bURB with drone. That back portion that makes it an SUV also makes a nice resonator/vibration amplifier.
 
Was yours the earlier model overdrive or the updated one? I know they changed design sometime in the last few years
 
You must log in or register to reply here.
Back
Top