P38 DSE 97 Auto 1st Gear JOLT

jwaldron · Dec 4, 2010

Sarstad... dunno if any of the components would be the same between a p38 and ranger... but something to think of I guess.... Vehicle is back in garage now anyway as per update on post #19 via the AA.

sarstad · Dec 4, 2010

jwaldron said:
Sarstad... dunno if any of the components would be the same between a p38 and ranger... but something to think of I guess.... Vehicle is back in garage now anyway as per update on post #19 via the AA.

a auto grebox is in ground the same body valve it a plate in the button of the gear box over the filter . , it is separated from the gearbox with a gasket .
when that gasket leeks the oil prosier in will drop and you have problems with gears

jwaldron · Dec 8, 2010

Latest update from the garage is that the front diff has gone. Bearings collapsed so this may have been the cause of the org knocking / jolt on the change down.

My worry is that something caused the diff to fail (other than it just failing of course). Surly the rear diff would have taken the same battering if it was due to wind up from the VC unit being at fault?

Datatek · Dec 8, 2010

jwaldron said:
Latest update from the garage is that the front diff has gone. Bearings collapsed so this may have been the cause of the org knocking / jolt on the change down.

My worry is that something caused the diff to fail (other than it just failing of course). Surly the rear diff would have taken the same battering if it was due to wind up from the VC unit being at fault?

VCU failure usually destroys the front diff first

wammers · Dec 8, 2010

jwaldron said:
Latest update from the garage is that the front diff has gone. Bearings collapsed so this may have been the cause of the org knocking / jolt on the change down.

My worry is that something caused the diff to fail (other than it just failing of course). Surly the rear diff would have taken the same battering if it was due to wind up from the VC unit being at fault?

Rear diff is direct coupled to transfer box. Front diff runs through VC. The front diff has to compensate for differential rotational speed of the wheels as the steering is turned therefore fails first. I hardly think a failed VC will cause a bearing failure, far more likely to destroy planet wheels and pins first.

jwaldron · Dec 8, 2010

Datatek said:
VCU failure usually destroys the front diff first

I guess that's something else on the check list then.

I do get a vibration at really slow revs (just above idle) up to about 900rpm.... but no issue on full lock like the normal VC failure explanations and the props don't have any slack and UJ is new.

The rubber plate has a very small crack around one of the nuts - which I put the vibration down to - could this be the VCU you think? This is assuming that the new Diff sorts out the clucking change down of course.

Datatek · Dec 8, 2010

jwaldron said:
I guess that's something else on the check list then.

I do get a vibration at really slow revs (just above idle) up to about 900rpm.... but no issue on full lock like the normal VC failure explanations and the props don't have any slack and UJ is new.

The rubber plate has a very small crack around one of the nuts - which I put the vibration down to - could this be the VCU you think? This is assuming that the new Diff sorts out the clucking change down of course.

Rubber plate

jwaldron · Dec 8, 2010

Datatek said:
Rubber plate

sorry. its the rubber prop coupling.

I've done a lot of reading about what the VC does and how it works. And to be honest, the more I read the more paranoid I get! lol

Most people have a jerky full lock turn as the centre diff is locked (VC). This has also been described from some as resistance when your in reverse.

I don't have the jerky ride on full lock but do have the vibration (jerky ride) on low throttle as described above even in a straight line... I'm talking hardly touching the throttle here. Example would be when you want to crawl fwd. Not every time, but every now and then; warm or cold, turning or not.

I have always had to give reverse a little more throttle than fwd gears but then again - the gearing is different anyway so never thought anything of it.

I think I'll be requesting the VC to be checked over before I take the car back - even just out of piece of mind.

jwaldron · Dec 10, 2010

update: Vehicle due for pickup Monday with a guaranteed second hand diff and a px side abs sensor as the old one had stuck itself into the hub. VC has been checked and is fine so with fingers crossed it looks like the front diff was the cause of the clunking. Although the proof will be in the puddling after I get her back and take her for a spin.

Otherwise its a chain in the TC or the gearbox on the way out. Anyone know how to check the chain without taking the transfer box off ? (thinking ahead here and worse case... well no - gearbox would be worst case but you know what I mean).

jwaldron · Dec 16, 2010

Right then... got the car back from the garge today. Guy said that he'd test driven it about 10miles without any clunks at all. Was happy with the price so paid as fault was clear.

WELL BUGGER ME!!!

inside 50miles (all was well to start with mind you) the clunks back. So it wasn't the front diff. I also have some other issues now so I'll recap quickly on the faults together as I somehow think they are related.

1) On very light throttle (but enough to just make you move) I get a judder. I drive an auto.. but would describe the issue as if I had a manual and was just on the bite point and holding it on it to make the car judder for a bit.

2) The clunk is back. Softer I agree but still bloody their. It only happens when you cause the box to change DOWN. Example. Come off a slip road up to a roundabout and slow (not coast) to the halt... I get a noticeable jerk feeling as she slips down into 2nd gear and a soft clunk (metallic sound) then a similar jerk but louder clunk sound as she slips into 1st.

3) If you approach a roundabout but don't have to stop... ie go back on the power (normal, not like a mad man) to pull away then I get a quick slap / clunk as the drive is taken up or she clunks into second (I assume) to do what is being asked.

4) When under acceleration the gear changes are normal apart from when she torques up just before 50mph (assume 3rd), then feels like changes gear (assume into 4th) with a drop in the revs on the change then immediately the revs rise (no longer in line with speed) for about 500rpm then drop back down and torqued up. I can't workout if she's torquing up in 4th and dropping back to third for a short spell before going back into 4th or if its like torquing up whilst revs rise then drop suddenly, but the hole process is a lumpy gear change.

5) Since the front diff I have a slight vibration feeling when you apply power (and I'm sure I can hear a rumble type noise) from what feels and seams to be behind me... just under my ars, but feels like it may be left rear (could be acoustics playing up)... If you come off the power, the rumble and or noise goes away. connected?

I've read as many posts as I can find for these in isolation, but can't find a connection. And I have thought I could be unlucky and have multiple issues, but the timing is all too wired. They all seam to be together. I had none of them, now all of them.

I've read about Viscous units.. garage said mines fine, read about TC, flex plates, output shafts, Transfer chains, selector switches, TPS's, Props and A joints. Does anyone know or have any idea where I can start or am I just better off Changing the bloody box and transfer case (inc TC).... I have no idea on cost though.

Any help would be really appreciated. I'm just about to ditch the bitch :mad2:... If I wasn't out of work I'd dump it and buy a newer one... but cash is tight and could end up swapping her for a lemon (or should I say another one!). Grrr... so frustrating :frusty:. I'm an educated person but I don't have the experience to figure this out. Anyone local that could take the bitch for a spin and try and diagnose or point me in the right direction?

jamesmartin · Dec 16, 2010

you can test viscous unit by jacking up front wheel with gear box in neutral and turning front wheel with 3ft bar on wheel nut ,should turn with resistance if it wont turn viscous seized ,can be removed without removing t/box ,second hand front diff not a good idea unless you checked brgs usually worn ,put gear box in park and remove both props ,rotate output flanges to see what backlash you have in t/box,driving with one prop in turn isolates either axle ,dropping a little oil out of boxes can give clue to which (metal filings or silver sheen in oil ,or black or burnt smell with auto) any alteration in gear change would indicate auto box problems

jwaldron · Dec 16, 2010

The front diff was sourced by the garage and had a guarantee so if that's found to be the problem then it can go back. But its strange that two front diff would have same fault. Same noise, same feel same situation.

The garage said that the VC was ok as they had to turn it 90deg to fix the bolts back on for the front prop.... plus 45miles ish would't chew up the front diff. Or would it?

I don't know why (and its not knowledge) I get the feeling that it is internal to either of the boxes... due to the gear change symptom I have on torque up I probably think its the main box at fault but will probably fit a transfer box to save on labour in case (keep the old Transfer box for future)...

It could again be an ECU playing up... but without a good known working unit to swap out to check... am stuck.

One thing I may do is disconnect the Hot start fix I have as when I first installed it - It gave me wired gear changes (must of split the wrong cable)... see if that does anything.

LeP38 · Jun 29, 2023

jwaldron said:
The front diff was sourced by the garage and had a guarantee so if that's found to be the problem then it can go back. But its strange that two front diff would have same fault. Same noise, same feel same situation.

The garage said that the VC was ok as they had to turn it 90deg to fix the bolts back on for the front prop.... plus 45miles ish would't chew up the front diff. Or would it?

I don't know why (and its not knowledge) I get the feeling that it is internal to either of the boxes... due to the gear change symptom I have on torque up I probably think its the main box at fault but will probably fit a transfer box to save on labour in case (keep the old Transfer box for future)...

It could again be an ECU playing up... but without a good known working unit to swap out to check... am stuck.

One thing I may do is disconnect the Hot start fix I have as when I first installed it - It gave me wired gear changes (must of split the wrong cable)... see if that does anything.

jwaldron said:
Right then... got the car back from the garge today. Guy said that he'd test driven it about 10miles without any clunks at all. Was happy with the price so paid as fault was clear.

WELL BUGGER ME!!! inside 50miles (all was well to start with mind you) the clunks back. So it wasn't the front diff. I also have some other issues now so I'll recap quickly on the faults together as I somehow think they are related.

1) On very light throttle (but enough to just make you move) I get a judder. I drive an auto.. but would describe the issue as if I had a manual and was just on the bite point and holding it on it to make the car judder for a bit.

2) The clunk is back. Softer I agree but still bloody their. It only happens when you cause the box to change DOWN. Example. Come off a slip road up to a roundabout and slow (not coast) to the halt... I get a noticeable jerk feeling as she slips down into 2nd gear and a soft clunk (metallic sound) then a similar jerk but louder clunk sound as she slips into 1st.

3) If you approach a roundabout but don't have to stop... ie go back on the power (normal, not like a mad man) to pull away then I get a quick slap / clunk as the drive is taken up or she clunks into second (I assume) to do what is being asked.

4) When under acceleration the gear changes are normal apart from when she torques up just before 50mph (assume 3rd), then feels like changes gear (assume into 4th) with a drop in the revs on the change then immediately the revs rise (no longer in line with speed) for about 500rpm then drop back down and torqued up. I can't workout if she's torquing up in 4th and dropping back to third for a short spell before going back into 4th or if its like torquing up whilst revs rise then drop suddenly, but the hole process is a lumpy gear change.

5) Since the front diff I have a slight vibration feeling when you apply power (and I'm sure I can hear a rumble type noise) from what feels and seams to be behind me... just under my ars, but feels like it may be left rear (could be acoustics playing up)... If you come off the power, the rumble and or noise goes away. connected?

I've read as many posts as I can find for these in isolation, but can't find a connection. And I have thought I could be unlucky and have multiple issues, but the timing is all too wired. They all seam to be together. I had none of them, now all of them.

I've read about Viscous units.. garage said mines fine, read about TC, flex plates, output shafts, Transfer chains, selector switches, TPS's, Props and A joints. Does anyone know or have any idea where I can start or am I just better off Changing the bloody box and transfer case (inc TC).... I have no idea on cost though.

Any help would be really appreciated. I'm just about to ditch the bitch :mad2:... If I wasn't out of work I'd dump it and buy a newer one... but cash is tight and could end up swapping her for a lemon (or should I say another one!). Grrr... so frustrating :frusty:. I'm an educated person but I don't have the experience to figure this out. Anyone local that could take the bitch for a spin and try and diagnose or point me in the right direction?

Did you ever find the cause of the jolt from 2nd to 1st? I'm getting the same problem.

P38 DSE 97 Auto 1st Gear JOLT

jwaldron

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sarstad

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Datatek

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wammers

No longer with us, RIP

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