Outer Limits 4x4 Board

hi all. im a newby to this site was hoping somone could help me.
i have a 1990 patrol 4.2 diesel lwb.
just fitted 6inch lift kit from bbm comprising of. springs, shocks, brake lines, upper and lower rear arms, dropped front arms, rock rods.
i drove the car at low speed. all good. took it on the free way and damn, massive grinding noise from the unis. now i know i have to space the gear box cross member down to correct the angle. but how much?. and will i need to modify the engine mounts? i also know that i need to modify the rear crossmember and i will do so this week along with modifying the front cross member to clear the front shaft. is there anyone that can give me some pointers, maybe somone on the nsw central coast that can come give me a hand. i had a mate who pointed me in the right direction i think but it would be great to hear from somone with a GQ who has had and over come these issues. thanks

Hello and welcome.
Yes sounds like the transmission crossmember needs spacers. Looks like you have accounted for almost everything else.
As far as how much, well, if not enough; you won't get rid of the problem, if too much; you relieve the problem on the rear uni's and start to stress the front ones.
A mate of mine temporarily used different sized nuts as spacers for the trans X-member till he found the right one, then had proper spacers machined up. He had to get longer bolts for the X-member as once the spacer nuts go in, the existing bolts don't have enough thread left on them to be safe.
Yes you will need to mod the front and rear X-members if you are going off road with it. I specifically only went to a 4" lift to avoid this.

Couple of things:
1. You will need to make sure to put a decent load on the front tail shaft (ie work the 4Low stick) to hear any noise from the front uni's that will show the spacers are too big.
2. Most of the time the engine mounts will tolerate the changed angle but keep in mind thier life expectancy will be shorter if the angle doesn't get moved.
3. Expect the radiator fan to rub on the shroud a bit. Mods may be required.

Have fun
Dave

Did you swap the rear tailshaft end for end? if not, i'd be looking there as they don't take much to rub on the chassis crossmember.

cheers

OONDY

Hi,

I've got some gearbox spacers if you want them. Can't use in my GU cause of the rock sliders bolting onto the cross member.

Peter

morewheeldrive wrote:just fitted 6inch lift kit from bbm comprising of. is there anyone that can give me some pointers,

Have you called Rick at BBM at all?

Yes calling the distributer is the first step then possibly reverse shaft and on my old one we took an inch angle out of the cross member and welded angle in. Unsure weather this is frowned upon but if done correctly no reason why it should be.

You don't have to space the gearbox crossmember at all. Adjust your new rear arms to sort out your universal joint angles (running at the same angle) and you should be right. Will most likely have to flip your rear driveshaft to clear the crossmember as well.

Nelso wrote:You don't have to space the gearbox crossmember at all. Adjust your new rear arms to sort out your universal joint angles (running at the same angle) and you should be right. Will most likely have to flip your rear driveshaft to clear the crossmember as well.

rear arms do nothing for the output shaft uni. only change the diff pinion uni angle.

morewheeldrive wrote:

Nelso wrote:You don't have to space the gearbox crossmember at all. Adjust your new rear arms to sort out your universal joint angles (running at the same angle) and you should be right. Will most likely have to flip your rear driveshaft to clear the crossmember as well.

rear arms do nothing for the output shaft uni. only change the diff pinion uni angle.

You dont have to have them pointing at each other. Just have to make the angle the same. So in a lifted car the pinion is pointing higher than std. So slight longer lower arms (the way I would fix it) or slightly shorter upper arms. Will put the uni's back into sync.

morewheeldrive wrote:

Nelso wrote:You don't have to space the gearbox crossmember at all. Adjust your new rear arms to sort out your universal joint angles (running at the same angle) and you should be right. Will most likely have to flip your rear driveshaft to clear the crossmember as well.

rear arms do nothing for the output shaft uni. only change the diff pinion uni angle.

So when you adjust your arms to rotate the diff so the pinion is lower what do you think happens to the angle of the transfer case uni? Either you fit some sort of flexible drive shaft or that uni has to increase in angle too.

Rotate your diff so that both drive shaft flanges are parallel (easiest way), so your universal joints are running at the same angle. If they are not they will be unbalanced and will vibrate.

This topic has been discussed at length plenty of times so my suggestion is to dedicate some time to searching and reading. Not only will you find explanations as to why they need to be set up this way you can also learn how to do it.

Drop in and see Jamie at The 4x4 Specialists in Charmhaven, he is an Authourized BBM Dealer.
As mentioned, turning the front shaft end for end can help, but my first thing would be to get a 12mm transmission spacer in there.
If you have any questions at all, please, do not hesitate to call me and we can see what needs to be done.

Cheers,

Rick.

BBM Rick wrote:Drop in and see Jamie at The 4x4 Specialists in Charmhaven, he is an Authourized BBM Dealer.
As mentioned, turning the front shaft end for end can help, but my first thing would be to get a 12mm transmission spacer in there.
If you have any questions at all, please, do not hesitate to call me and we can see what needs to be done.

Cheers,

Rick.

thanks to all. im in the process of modifying the gearbox x-member as well as dropping it two inches. im also modifying the rear x-member to go over the tail shaft instead of under it. ill let yas know how i go. im sorted out my rear uni angle, its better but not ideal but thems the breaks i guess.

i would not drop it 2 inches ,some thing does not sound right daz

daz4b wrote:i would not drop it 2 inches ,some thing does not sound right daz

well its actually like 40mm, iv dropped it 20mm already but the uni @ the back of the gear box is still on and angle and im still gettin some chatter as i juuuuuust come off the throttle at high speed which was waaay worse before i spaced the box down so the way i figure it another 20mm will bring the uni angle straight and stop the load on the uni which will stop the chatter and remove the load off the rear output shaft bearing.

did you say it was a lwb ,10mm packer should be enough,did you turn rear shaft around if so you could have the chatter from this,scollop the front shaftout for front shaft daz

daz4b wrote:did you say it was a lwb ,10mm packer should be enough,did you turn rear shaft around if so you could have the chatter from this,scollop the front shaftout for front shaft daz

yeah i did turn it round, u may be right. once if modifyd the rear x-member to go over the tail shaft then ill turn it back round because it wont be an issue and ill see if the chatter stops. if not ill try the extra spacing. i few people have told me that each patrol can differ from he next when fitting the 6". some take more spacing than othrs. but wel will see i guess. ill keep yas posted and put some pics up of my mods to the cross members

if your droping your transfer down 40-50mm so you can have a 6inch lift then you might as well just gone 4 inch saved some cash and had the same ground clearance under your car......
I think you have a set up prob not a spacer prob if you needed a spacer that big I hope it would come with the kit

Mayhem Mat wrote:if your droping your transfer down 40-50mm so you can have a 6inch lift then you might as well just gone 4 inch saved some cash and had the same ground clearance under your car......
I think you have a set up prob not a spacer prob if you needed a spacer that big I hope it would come with the kit

yeah i originally thought the same but i checked over everything and its fairly hard to mess up installing a bolt on kit i may aswell throw my trade certificate away if i didnt get that right. Still there is always something that could be wrong. In hindsight i should have gone for 4 inch. Much too late for that and im not gonna give up. Im gonna get it right if it take's me forever. I think ill call rick from bbm today.

That would be good. I was in the middle of typing you out a PM yesterday when we lost power. I was also going to give you a call today, as what you have described should not be a huge drama to overcome unless you have an underlying problem.
Certainly dropping the crossmember 40-50mm is NOT the answer!
I look forward to hearing from you mate.

Rick.

ok so iv put new uni's in the rear shaft, got the gear box spaces in, flipped tail shaft, modified cross member for front shaft clearance, greased and checked and tightened everything and still im getting this stupid grinding noise when coming off throttle at 100km and over and when pushing the clutch in at same speed. Any more thoughts?

morewheeldrive wrote:ok so iv put new uni's in the rear shaft, got the gear box spaces in, flipped tail shaft, modified cross member for front shaft clearance, greased and checked and tightened everything and still im getting this stupid grinding noise when coming off throttle at 100km and over and when pushing the clutch in at same speed. Any more thoughts?

I am running the same 6" lift from BBM all I had to do was flip front and rear tail shafts and then 'scollap' (can't spell but who cares) out t of the front cross member BUT this was only as at full flex the front shaft still just touched. I did at the same time replace the uni's as they were a bit growlly but that was it. It seems like you are going to extremes with the cross member spacing and replacement. I have since also installed 10mm longer trailing arms to change the angle but generally this kit is fairly bullet proof for the GQ lwb, I have 2 other mates who installed the same thing with no probs so hopefully Rick can sort it out for you easily.

morewheeldrive wrote:ok so iv put new uni's in the rear shaft, got the gear box spaces in, flipped tail shaft, modified cross member for front shaft clearance, greased and checked and tightened everything and still im getting this stupid grinding noise when coming off throttle at 100km and over and when pushing the clutch in at same speed. Any more thoughts?

What did your pinions feel like when you did the unis?

morewheeldrive wrote:ok so iv put new uni's in the rear shaft, got the gear box spaces in, flipped tail shaft, modified cross member for front shaft clearance, greased and checked and tightened everything and still im getting this stupid grinding noise when coming off throttle at 100km and over and when pushing the clutch in at same speed. Any more thoughts?

Are you in 4WD?

Are your hubs locked in, but only in 2Wheel Drive?

I would look at all 4 uni joints, front and rear slip yokes for slop and wear and tear and then rear pinion bearings.

If none of that fixes it, I would check the driveshaft angles and front end.

I would say the car already had a slight problem, and the lift has magnified it.

ha ha just an update for all. After all the shit i went through with the noise in the drive line. I did some thinkin and after everything iv done i decided as a last report id put my tail shaft back around to its original position seeing as id modified the rear tube cross member to go over it i had plenty of clearance. I almost weed a little bit when i drove my truck home from work and the noise was gone. Seem's my slip joint was use to goin in one direction and when i changed it, it was.nt pleased. So there ya go. If your doin six inch lift it might pay to mod the cross member before you turn your shaft around. Thanks to all for your help.

what an ordeal, good to hear you got it right in the end