86 560SEL

I have removed the drive shaft to change any parts that might need to be and I have noticed that there is about 3/4" play in the rear end ( I can move the star looking thing where the drive shaft bolts to about 3/4 " before the gears catch and the wheels turn) This would explain the loud thud when going from P to D or P to R. I am no mechanic but should there be so much play? If not what would the remedy be?

Thank for any input

Jerry

 

I guess I should have called it differential instead of rear end. Anyway I have looked all over the net and there is no info on differentials besides used ones for sale.

 

axial movement?

was it the cross joint or the splined flange?

 

I would love to let you know sleepwalker but I do not know either of those parts. I am talking about the play when I grab the part where the flex disk/drive shaft bolt onto the rear end (looks like a star with 3 holes). The reason why I was asking is that when I pump the accelerator or put the car from P to D but mostly from P to R I hear and feel a thud in the rear axle. Which would make sense is there is too much play somewhere.

Info on differential is hard to come by, I have searched all day and no luck.

Do you drain and fill the transfer case separetely from the trans?

Thanks

 

it's the input flange to the differential pinion drive.

the travel you said is 3/4"? the maximum allowable clearance between the pinion and ring gear is about 0.5 mm.

i would say the radius diameter of that flange is about...4 inches. a travel of about half an inch is acceptable.

the differential will produce humming noise if the adjustment is out of tolerance.

was your engine rpm not more than 750? high rpm will cause jerk on P/N to D/R shift.

was the vacuum pipe for the modulator attached and no leak? without vacuum, the pressure for shift is high and cause jerk too.

do you have "B" shift? if the B switch is faulty, you will get jerk too.

was the control cable for transmission properly adjusted?

transmission oil viscosity is good and no sign of water or moisture?

don't you feel that the problem might be cause by the transmission pressure damping?

 

Regarding the RPM: The car always idle right at 500rpm

vacuum pipe for the modulator: I don't know where it is, my cd manual has no info on trans besides fluid change.

Yes I have a B switch, and I found your post relating to B switch testing.

"ignition on

0 shift to p, r, n, or d

1 jack up the car

2 ignition or start the engine (if your jack is 101% secured)

3 go under the car on the rear end of transmission

4 look up and see the wire

5 if you see the wire, go and get a voltmeter, or multi tester, or test light

6 pull out the wire from the kick down solenoid

7 check if there is voltage or current on it.

* have voltage = faulty B switch

*no voltage = check the kickdown solenoid. you will find a small piece of rubber blocking the hole! remove it. apply 12 volts to it. you must hear and feel it "clicking" and see the plunger inside moving.

step 2:

have someone inside the car and push the accelerator pedal all the way to the floor till the kickdown switch is acruated (he can feel the thud).

repeat steps 0 to 7

have voltage = good kickdown switch
no voltage = bad kickdown switch

step 3:

shift to "B"

repeat steps 1 - 7

have voltage = good B switch
no voltage = bad B switch "

Don't know where control cable is?

Regarding fluid it looks good as far as I can tell.

I have changed the drive shaft center bearing, flex disks look really good they are 9 months old and the guy who sold me the car showed me the receipt they only have 6000 miles on them. If you had a drawing of the trans that shows the location of the parts you are talking about it would be great. All the books I found are $200 and over for MB transmission.

Thanks for everything sleepwalker.

 

if you are under the car and look at the middle right side of the transmission, you will see a round plastic box with a vacuum hose attached to it.

with engine running, detach that hose and feel if there is a vacuum on it. it should have vacuum all the time.

if this vacuum hose is disconnected or no vacuum, your transmission will engage very harsh.