Massive tranny issue! Need help!

[jessetv]

I had an off road out of Houston install a 16" lift on my 02 Tahoe, as most of you know 6 days after I picked up my lift the tranny blew up, Tahoe had 105k when the tranny went bye bye, Had it overhauled 1700.00 later. After driving in for 2 weeks tranny blew out again! Tranny shop says it WONT wty the tranny and i have to pay all over again...WTF! They say I will keep blowing up the tranny beacuse the angle from the tranny and the driveshaft is wayyyyyyyyyyy to steep and inccorect, they blame the off road shop for not having enough foward thinking to have a solution for this problem! They (tranny shop) say that that they wont wty any repairs with the angle that messed up, they really think that the truck shouldnt have been offered to be lifted that high due to this angle issue! They reccomended a double carden joint but still say that unless the angle is corrected, I will continue to damage trannys and basically im F*CKED! I spent ALOT of money on this truck already and I am soo very worried that I made a mistake.
They say that the angle of the ds, and the weight/height of the tires (40" Toyo MTs) is gonna continue to break the tranny!

Guys I REALLY REALLY NEED SOME HELP HERE!
Thanks

[Cwilli85]

what ring and pinion gears are you running?

[bggrnchvy]

There is entirely too little information about whats going on here.

Other than that angle on the output shaft doesn't hurt transmission internals. Unless you're breaking output shafts on a 2wd tranny they're FOS.

Even stock 60e's should last longer than a few weeks on an ungeared rig running 44's. I'd bet the trannies this shop is 'producing' are poor to begin with.

[Blue-Z71]

my friends rebuilds and beefs up 4l60es... but im in tn... hope somehow you can get this situated man

[jessetv]

I have the 4.88 on the rear end. with the 40" toyos and the 16" lift.

I have blown the original tranny once (6days after lift was installed) Then I blew the t/c a week later. then I installed a tranny cooler and 2 weeks BOOM blew out the tranny again!

Just dont know WTF is going on here!

The second time around the tranny shop says that the input shaft is completely broken AGAIN and a ton of internal parts are f(&ked up!

[Blue-Z71]

who did you lift? i lived in katy my whole life so i may no them

[Cwilli85]

I'm not an expert on trannys but i don't understand a steep rear driveshaft angle breaking an input shaft. Someone may correct me.

[Blue-Z71]

ive "heard" driveshaft angles on lifted trucks can mess with trannys, but i have no personal knowledge to back that up

[jessetv]

Not just the input shaft a WHOLE ****LOAD of other parts inside the tranny as well, Like i said, I just don't know if my tranny shops sucks or is that steep of an angle gonna CONSTANTLY give me problems? I cant have a truck always breaing down! I dont feel safe when I drive it!

I know these kinds of trucks are toys, but to qualify to be a toy i have to ENJOY it!
NOT HAPPENING RIGHT NOW!

[jayblizzo187]

So you guys dont think a rear driveshaft binding would cause transmission damage? If the it is at such a steep angle that the d-shaft completely stops moving while the transmission is trying to turn it wouldn't that hurt the trans. a little bit?

[mntahoe]

On a Turbo 350/400 I'd say no way a lift would break a trans. Back in high school, a buddy had '74 Chevy lifted enough that the floor was about waist high. He changed u-joints more often than oil, but never a hint of trans trouble.

However, the 4l60e is actually a very fragile transmission. Particularly second gear. It has to be applied gently or it will snap like a twig. That's probably what is happening in your case. With a very sharp angle, the drive shaft will "pop" with every rotation, which I imagine would shock the trans internals. A 4L80 (which is really a TH350 with overdrive) or TH400 could probably take it and you'd just be replacing u-joints once a month.

[bggrnchvy]

Is the drive shaft binding?

If it is rotate that pinion and get a CV on the t-case output regardless.

If the shaft is binding, every instance I've ever seen has resulted in a yoke snapping or a u-joint blowing up. Never has the transmission been the failure point. It's odd to have the drive shaft survive time and time again and have the drive train bear the brunt of the abuse.

Originally Posted by mntahoe

On a Turbo 350/400 I'd say no way a lift would break a trans. Back in high school, a buddy had '74 Chevy lifted enough that the floor was about waist high. He changed u-joints more often than oil, but never a hint of trans trouble.

However, the 4l60e is actually a very fragile transmission. Particularly second gear. It has to be applied gently or it will snap like a twig. That's probably what is happening in your case. With a very sharp angle, the drive shaft will "pop" with every rotation, which I imagine would shock the trans internals. A 4L80 (which is really a TH350 with overdrive) or TH400 could probably take it and you'd just be replacing u-joints once a month.

And the 80e is a TH400, plus an overdrive gear and clutch set and an electronic valve body, not a TH350.

[chevybig10]

The transmission shop is 100 percent CORRECT.

I have been a driveline mechanic making custom shafts out of aluminum, steel, high angle cv's heaver wall tube, carbon fiber drivelines, shortening and lengthening axles etc.

A ujoint can handle 4 degrees of angle MAX before it builds heat from over twisting back and forth, torque on it builds heat and pressure on needlebearings gets super high...so you tear out ujoints.

When you run high angle......instead of handling the slight angle the ujoints now start to bind each turn. They go through extreme pressure binding up and releasing each turn.

this binding creates hich pressure on your yoke on the transmission and bushing inside the tranny, as well as your tc. It creates a HUGE amount of vibration as well that tears out internal bearings and bushings like there is no tomorrow.

If you lowered the transmission about 6 inches and rocked both diffs way up to straighten out the driveshafts....you would then increase the angle on your front shaft that it would rip itself out.

Welcome to lifted trucks with ****ed up drivelines. If you want to have the rear last to get you around you kill off the front. Maybe a driveshaft each month for around 500 bucks sound good?

there IS a solution. Custom driveline.

Think of the old cadillacs and lincoln driveshafts. A cv joint in the front...and in the rear. The ats yoke bolts up to a cv in the front, and the rear is flanged to bolt to a flange on the diff. This needs a whole new shaft with 2 cv joints that have 2 ujoints in each one...and a flange yoke made and welded and drilledtapped to accept the cv.

This dual cv rear shaft will help you

Or

Run your transmission output like a jackshaft and put in a chain driven transfer case a foot and a half lower. Not the output of your power is a foot and a half lower to go to your rear diff. The front shaft could do something similar on the diff.....but I know in a duramax a 2 inch tube comes to within 1/4 inch of the transmission side....so you are limited.

there is now a yoke that has the spline shaft that goes into your tc that has a cv head with little 1310 ujoints that will work.

Then your front has a cv....your front diff must be rocked up to straighten out your driveline angle. and you will cancel out the high angles on your tc and tranny and be back in business.

Prepare to spend money.

[fastfew]

I think his truck is 2 wheel drive if thats the case , all you have to do is have the for wheel drive shop build some spacers to lower your trans crossmember so the u joint angle is less than 4 deg.if you are getting bad drive shaft vibration it will tear the trans apart............ i had to drop the trans xmember on my 2 wheel drive jeep for the same reason........

[jessetv]

It is actually a 2wd and your solution sounds GREAT, do you think that ALONE will be able to be accomplished? So am I clear taht id the angle is less than 3or 4 degrees, I should be fine and stop this freakin tranny issue?
How can you lower the tranny when its bolted to the engine?

[mntahoe]

You just lower the trans crossmember which will make the trans (and engine) point down toward the ground more. Your rear axle will have to be rotated up so that it is approximately parallel. Ideally, they wind up pointing directly at each other and you have zero u-joint angle, but you also have to allow for axle wrap.

[bggrnchvy]

The angle does not have to be less than 4*, I don't care what a driveshaft mechanic with a limited scope of experience has to say about it.

We regularly use drivelines with 10-25*'s of angle at rest and they live for thousands on thousands of street driven and trail beaten miles.

My rear driveshaft has 13*'s of angle and it's been in the truck since 04 with the same u-joints which are still perfectly tight.

The goal is building a driveshaft that can handle the angle and modifying the surroundings so it can be accomplished. Usually the easiest change is pinion rotation. Cut and weld spring perches or move link mounts so that the pinion is pointing at the t-case output minus 2-3*s to account for deflection in the springs or bushings. Then have a CV (note single single CV, it's not a double CV unless you have 4 u-joints on the same shaft with 2 ball pivots and 2 H crosses) added to the t-case/tranny output side that will accomodate the angle at rest and all the way to full droop.

Jesse at HAD is marketing a new daily driven 42* CV if you need something that extreme. My guess though being it's still a 4 door fullsize is that you're rear angle is at max droop less than 32* so I'd just get with HAD or Tom Woods and get a shaft with a 32* CV made.

[DarkCharisma]

What does the shop that lifted the truck have to say?

What is the extent of the warranty terms? Unless they specifically state they will not warranty transmissions on vehicles with aftermarket suspension systems, they're just blowing smoke up your ass.

[06BLACKZ71]

I think the shop that lifted ya should have share some of the responsibility here... Its like buying a car with a tpw package.. Someone at uhaul would prly advise against towing another car with a car... right? lol they have some experience with lifts... I would definately have a conversation with the ppl that sold you the lift...

[jessetv]

The Off Road shop said they have done this EXACT lift on lots of Tahoes...2 of them still had fact 3.73 gears on 44 truxis. I have seen another one of there tahoe's that has a 18" lift and a stock tranny,
Don't know why my setup is so messed up!