Driveline vibes

[toomanycars]

I bought myself a "new" Samurai the other day. I've given up on trying to gt my 1600cc conversion to work (badly machined conversion plate)...so i sold it, got £1300 for it, almost $2500!! And I bought this beauty for £500 ($900) - what a sucker the seller was:

1988 Samurai (bit rusty, nothing some sheet metal and a welder can' fix)
Spring over lift and 1" longer shackles, 31" tyres
Rear disc brake conversion
the best bit - fitted with a 2.0l Ford engine with about 115hp

The engine conversion includes a 5 speed ford gearbox and custom mini dirve shaft to t-case.

The problem is accerating hard in 1st and 2nd, there is very bad vibration/juddering until you reach higher speeds...once you hit 25/30 in 2nd there isn't any noticeable vibe...at high speeds there's nothing even up to 80mph...While it's vibrating, the vibrations can be felt very stongly through the t-case stick, and very faintly through the gear stick....so I'm guessing the problem is somewhere behind the t-case...

The universal joints in the rear driveshaft looked pretty worn so I stuck in new ones...no difference. The angle of the shaft looks pretty severe to be honest. So what's the solution? shims in the rear? Custom high angle shaft?

Thanks for any input

(ps: haven't driven it in 4wd yet, but want to get 2wd working properly as it's going to be a daily drive).

[DevilJeep]

Is the t-case in the stock location?
Is the ford tranny the same length?
Might not have proper angle on the short shaft, which will cause vibes...

[DevilJeep]

Ohh and make sure the t-case mounts are good. May have been torn w/ more hp..

[toomanycars]

ford tranny is longer...the shaft is about 5" to 6" long now...but the angles on that shaft looks OK...I mean it's supposed to the more or less straight is it not?

It just seems wierd that it's at low revs/high torque, and completely disappears above 2500rpm and high speeds....

the t-case is in the stock position, with a new long mount....

[SilverZuk]

Sounds like spring wrap.

You need to pull against something and have some one watch the pinion and unload the clutch quickly, you don't have to take off - just watch to see what the pinion is doing. I have had the same problems, then I went to stiffer springs and CV rear shaft.
It's been fine ever since. I have had spring packs that were shot and caused binding.
You also need to check your pinion angle. You can make adjustments with the shackle length. I've done this too.

Get a front CV shaft from a Toy truck and swap it into the rear if it is just poor angle, and if it is spring wrap get stiffer springs or an anti-wrap bar.

If it were the intermediate shaft it would do it all the time, unless a mount was loose or broken.

[toomanycars]

I'l look into the toyota shaft...is it more or less a straight bolt in? does it need shortening/lengthening?

As for spring wrap...I had thought of that but didn't think that judder/vibe was he symptom of that...don't really want stiffer springs, so may go for a traction bar...

[SilverZuk]

You need to isolate the problem first.

Here's a write up about the toy d-shaft.
It can be bolt in with rat adapters, or if you have the spare flanges, you can drill it yourself.
You made need to kick your rear axle back a bit to make sure that the d-shaft is not too long.
Even if it is, it only costs about $40 to get one cut down locally.

[UZI 9mm]

Originally Posted by toomanycars

I'l look into the toyota shaft...is it more or less a straight bolt in? does it need shortening/lengthening?

As for spring wrap...I had thought of that but didn't think that judder/vibe was he symptom of that...don't really want stiffer springs, so may go for a traction bar...

(note- the descriptions below are in 2wd)

Kinda same deal with mine. I have an awesome anti-wrap set up, so zero spring wrap, but I get fairly serious shudder/vibes at exactly 2600 to 2900 rpm. smooth as glass up to 2600 and after 3000. Highway speed at over 100kph no problems at all.


I have just swapped in some cj5 front springs in the rear, and it resulted in exactly 1" more lift than the stock rear sammy springs I had in. Prior to the swap the 300-400 rpm shudder zone was definately noticable, but now it's quite intense.

At a suggestion from a friend when still having the stock springs, I slightly "preloaded" the pinion by adjusting the anti wrap bar in it's relationship to being parallel with the rear driveshaft (in effect, tilting the pinion up more to lessen angle) This helped a fair bit, so obviously pinion angle is pretty crucial when dealing with small u-joints that are at their max operational limit

Now that I have increased the angle by gaining another inch of lift, I will have to try to adjust the anti wrap again, or perhaps shim or re-perch at better angle.

I had initially thought my spring swap wouldn't net that much lift, because the shackle angle increased from aprox 10° off vertical to about 40° off vertical.

It's been virtually impossible for me (so far) to locate a decent shape toy cv shaft that the person doesn't want an arm and leg for, or too much modification required, resulting in diminishing returns (ie: I might as well just get a custom shaft made and be done with it)

Don't forget when these American dudes remark on how little they pay- it's a mere fraction of what we have to, and their population size has so much more to draw from, when it comes to the junk yards filled with toy goodies

[SilverZuk]

So you are saying that I should start buying up all the font toy d-shafts I see and selling them out of the U.S.?

I would expect to pay $40-60 for a d-shaft depending on the shape of it and bone yard.
If you are going to have one made, find one that you can drill the flanges for and have it cut down.
The toy's are nice because the flanges are small and you can buy a rockrat adapter if you screw one up or don't feel comfortable drilling something with less than 1/16" tolerance.

[UZI 9mm]

Originally Posted by SilverZuk

So you are saying that I should start buying up all the font toy d-shafts I see and selling them out of the U.S.?

I would expect to pay $40-60 for a d-shaft depending on the shape of it and bone yard.
If you are going to have one made, find one that you can drill the flanges for and have it cut down.
The toy's are nice because the flanges are small and you can buy a rockrat adapter if you screw one up or don't feel comfortable drilling something with less than 1/16" tolerance.

wow! :envy: have never personally seen or heard of one up here for less than at least triple above that! Everybody selling them here has got the rare "gold plated" versions...

After all was said and done shipping/taxes/brokerage/more tax, I believe my TT extended slip yoke was around $120.00 or so, all by itself.


toomanycars- I was eyeing a mid 70's jeep cj5 rear driveshaft as a pontential experiment, I guess over there they are even harder to locate than an early Toyota?

sigh.

[toomanycars]

jeep stuff will cost £££ over here...as will Toyotas stuff, and it's rare...in fact the most common 4x4 (for off road stuff) is probably the Landrover, closely followed by the Suzuki...

I'm starting to think that it's not the drive shaft....looking at some other zooks with similar height lifts, they're running with no vibes...I'm thinking it may be transfer case related...either worn mounts or bad case....when you accelerate, especially in 2nd gear form 1800-2800rpm, the transfer case stick shakes a hell of alot....

[UZI 9mm]

Originally Posted by toomanycars

jeep stuff will cost £££ over here...as will Toyotas stuff, and it's rare...in fact the most common 4x4 (for off road stuff) is probably the Landrover, closely followed by the Suzuki...

I'm starting to think that it's not the drive shaft....looking at some other zooks with similar height lifts, they're running with no vibes...I'm thinking it may be transfer case related...either worn mounts or bad case....when you accelerate, especially in 2nd gear form 1800-2800rpm, the transfer case stick shakes a hell of alot....

That would be a good thing to do anyway, check out the t-case mounts. Oh hey, have you looked at the jackshaft between the tranny and t-case's u-joints as well?

All things considered it sees a pretty easy life, but when I did mine, I discovered the u-joint closest to t-case was loose in the flange. It had ovalled out the joint's ears enough to no longer be tight. (I was able to push it out by hand!)

just a thought.

[toomanycars]

just thought I'd update this thread with the final installment...I went "wheeling" as you guys call it, and hammering it up a steep muddy slope in first, the 115hp out of the 2.0litre Ford proved too much for the wobbly drivetrain and I snapped the rear drive shaft...so took the shaft off, stuck it in 4hi and drove home 50miles on the front axle.

Anyway, starting to strip it out and wash it, I found that the previous owner had decided that only two bolts from t-case to long mount were sufficient to hold it in place! And even one of those was only finger tight

I could grab the case and move each end 2" up and down!! So, hopefully my days of shuddering are over....still need to source a drive shaft though...

[Canadian_Zuk]

Originally Posted by toomanycars

I could grab the case and move each end 2" up and down!! So, hopefully my days of shuddering are over....still need to source a drive shaft though...

I wonder what caused the d-shaft to break?