[HJ13]

Hello Jeepers,

I got converted my MM540XD 2WD to 4WD.

- Photos of 2WD (before conversion) -







- Photos of 4WD (after conversion) -












We tested the 4WD mode in sand and found it working well. In fact, I am quite impressed with the power of 4WD and high and low gears. However in 4WD mode, on road, the jeep was running very tight as if something is restricting it from moving. It was not running smooth at all.
Now I think it is due to different front and rear differential ratios.
The front is 44/9 and the rear (which is stock differential) is 47/11.
I am a little bit worried about any damaged caused due to this.


I had driven the jeep 6000+ KM before conversion - when it was 2WD.
So when I got it converted to 4WD, I immediately noticed the following differences:

1. Engine revving compared to speed
The engine (XD3P) revs more compared to the speed it delivers to the vehicle. Before on depressing the pedal the vehicle used to accelerate more compared to the sound of the engine heared. Now I can hear the engine producing more sound but the speed it delivers is not the same.

2. Loss of power
When the jeep was 2WD, I was used to start with 2nd gear from stand still without abusing the clutch. Now I have to use the 1st gear. Also I feel that overall power in each gear is somewhat reduced.

3. Reduced top speed
I used to touch to 100 KMPH with a feeling that still some power is left. Now after fully depressing the pedal I merely can touch to 85 KMPH.

4. Reduced rolling
The free rolling of the vehicle is less smooth and it covers less distance now.

5. Reduced mileage
Before conversion it was 13 KMPL (Average of Highway + City driving). Now it is not more than 10 KMPL.

6. Vibration on idle
Now on running idle the jeep vibrates more. I tried by setting the cross bolt but no luck. On this page: http://www.team-bhp.com/forum/4x4-ve...ricane-34.html Mr. Dhabhar mentioned about an internal spacer that should be used with the cross bolt. I have posted a photo of the cross bolt, can anybody verify whether it is correct?

I don't know much technicalities of jeep.
But first of all, I am to make the rear driveshaft straight.

For this I have purchased a rear defferential with driver side offset. It is with 44/9. My stock rear crown pinion ratio is 47/11 = 4.27 and as most of my driving is on highways I am to retain the same.
By reading Arka's post on http://www.team-bhp.com/forum/4x4-ve...-option-4.html I am assuming that it is possible to swap the crown pinion of 44/9 with 47/11 without changing anything else. Pls correct me if I am wrong.

The front defferential I purchased is having 44/9 = 4.88. So I will have to change that to 47/11 too. My local dealer is having a 47/11 crown pinion but he is not sure if they are for front defferential or rear. So one more questions is - are there different crown pinions for front and rear differentials?

Thanks for your time.

Regards,
HJ13

[fazalaliadil]

HJ13,

Tight running: The front diff. ratio is restricting the movement, match the front and rear diff. ratio's correctly and you will not have this problem. If you have not run the Jeep much on the 4X4 mode, you may not have damaged the internals.

The problems pointed out by you 1-5 are due to absence of free wheeling hubs. Even if you are not engaged in the 4WD mode, (while driving) the front wheels are rotating the front axles which in turn is rotating the gears in the front diff. There is an added load on your front wheels which translates into problems 1-5 stated by you. Free wheeling hubs is your answer.

Due to the added weight, don't expect the same mileage you which earlier achieved on a 2WD Jeep .

Problem #6: If the rubber foundation of the main GB is old and hard, change it. Do not over tighten the transfer case cross member bolt. Set the rubber foundations of the main GB and transfer case while running the Jeep on idle until you reach minimum vibration. Also check the engine foundations.The rear propeller shaft is very misaligned, needs to be corrected by replacing to the right oriented diff. housing (also contributes to vibration).

For better advice PM Arka, Sir Behram, Spike.
Regards,

[ex670c]

Originally Posted by HJ13

Hello Jeepers,

I got converted my MM540XD 2WD to 4WD.
================
The front defferential I purchased is having 44/9 = 4.88. So I will have to change that to 47/11 too. My local dealer is having a 47/11 crown pinion but he is not sure if they are for front defferential or rear. So one more questions is - are there different crown pinions for front and rear differentials?

Thanks for your time.

Regards,
HJ13

Hi HJ13,

Please align you rear Diff to the T-Case output.

Change the Rear Housing to a 4WD MM540, and swap all the necessary internals.

Please stick to 4.88 (44/9) diff ratio for better all around performance.

http://www.team-bhp.com/forum/4x4-ve...d-upgrade.html

Regards,

Arka

PS - incidentally my my 1996MM540XD was 2WD, before I converted it to 4WD

[svsantosh]

Hi HJ13,

1) As you said - replace your rear axle assembly to the right-offset 'driver-side-offset' one ASAP.

2) DONT engage/USE 4x4 capability with different Axle Ratios in front and rear diffs. Your GB will go for a toss.

3) If you have 4.27 in rear, have the same in front too - but as Arka said 4.88 front and rear is a ideal combo.

4) Also looks like you just got a KMT90 and plonked it in, why didnt you overhaul it once (assuming) it was from a scrap market? It will reveal a busted bearing or 2...

5) Get a spike arrestor cable and a Set of FWH's ASAP.

Keep us updated. Also some external pics of the jeep please?

[HJ13]

Thank you fazalaliadil for your reply.

I have contacted Mr Arun from Lamda Engineering and on request he has agreed to ship the hubs after I deposit the amount in the account.
If anyone has previous experience of ordering the hubs this way, please share.

The foundation of the main gear box is new. The mechanic says that the vibration will reduce over time as the rubber loosens. We have already tried adjusting the main foundation bolts and cross bolt while running the jeep in idle till it reaches minimum vibration.
But that 'minimum' is quite high compared to what it was before 4WD conversion. So now I think I should post a video now so the expert can judge whether the vibration is acceptable or not.
But as you have said that the misalignment of the shaft can also contribute to the vibration - I have pushed this problem at the bottom of the stack. Will take it on table once I am done with #1 to #5.

[HJ13]

Thanks Arka for replying.

I was hoping for your answer as I have read many posts of yours and your suggestion is very valuable for me.

I had selected 4.27 for the following reasons:
- most (85%) of my driving would be on highways, and the rest would be soft offroading
- I want good mileage
- 540 has no overdrive, so I am trying to compensate it somewhat with 4.27
- Rear stock crown pinion (4.27) has only 82KM on it. Need to purchase only new 4.27 front crown pinion. If I go for 4.88, I need to purchase new front+read crown pinions.
About scrap purchase, how should I judge the wear/quality of the crown pinion (or any gear for that matter) available?

Still as I am a newbie here (and I know incomplete knowledge can be fatal) and I know you through your numerous technical posts - your word would be the last one

Thanks svsantosh for replying.

Originally Posted by svsantosh

2) DONT engage/USE 4x4 capability with different Axle Ratios in front and rear diffs. Your GB will go for a toss.

I am not going to make the same mistake again. Sadly my mechanic didn't confirm the ratios and even he didn't recognize the root cause of the problem.
I have removed the front drive shaft (it was not a genuine one and was noisy) so one can not engage 4WD - so I am safe now.

Originally Posted by svsantosh

,
4) Also looks like you just got a KMT90 and plonked it in, why didnt you overhaul it once (assuming) it was from a scrap market? It will reveal a busted bearing or 2...

As per my mechanic, he had opened up the gear box + Tcase and parts were in good condition. Still I am planning for double checking it once I have the rear drive shaft aligned and FWH installed.

BTW can anybody comment on the letter written on the Tcase. They are 2000 and K/89 as seen in this photograph. What do they mean and what this Tcase is called?

Originally Posted by svsantosh

Keep us updated. Also some external pics of the jeep please?

Sure, I am to keep this thread updated.
Pls find them here: http://www.team-bhp.com/forum/introd...-team-bhp.html

[ex670c]

Originally Posted by HJ13

Thanks Arka for replying.

I was hoping for your answer as I have read many posts of yours and your suggestion is very valuable for me.

I had selected 4.27 for the following reasons:
- most (85%) of my driving would be on highways, and the rest would be soft offroading
- I want good mileage
- 540 has no overdrive, so I am trying to compensate it somewhat with 4.27
- Rear stock crown pinion (4.27) has only 82KM on it. Need to purchase only new 4.27 front crown pinion. If I go for 4.88, I need to purchase new front+read crown pinions.
About scrap purchase, how should I judge the wear/quality of the crown pinion (or any gear for that matter) available?

Still as I am a newbie here (and I know incomplete knowledge can be fatal) and I know you through your numerous technical posts - your word would be the last one

Hi HJ13,

4.27:1 for cruising is a good option. If you plan to replace the Front to 4.27:1 please the Crown & Pinion gear for uneven wear/polishing and obvious metal scuffing.

Just search online for Dana 44 and you will get an idea of how the differential looks and the parts.

As SV Santosh Pointed out please go in for a Spike-Arrester Cable and a Skid plate for the transmission.

Change the Air-Filter to the later model Paper Element/metal Drum Type.

Also check the gearbox breather plugs/vents and clean them.

Please Don't engage 4WD-Lo Ratio with out the Front Prop-Shaft, the result will be catastrophic.

Regards,

Arka

[svsantosh]

Originally Posted by ex670c

Please Don't engage 4WD-Lo Ratio with out the Front Prop-Shaft, the result will be catastrophic

Arka, some inputs here as to why' please? There are times where I have engaged 4Lo without locking the hubs and driven for few seconds before realizing it. Hope small errors are Ok?

[HJ13]

Just an update:

After adding Tcase, the old 2WD rear shaft was cut and welded for reuse. And perhaps that resulted in increased vibration while driving (may be because it is crossed - not aligned to Tcase output?). A friend who has a Lathe told me that the welding process will ruin the alignment or weight balance of the shaft. Only options is to weld the shaft while aligning it on lathe - and that is not possible here.

Also trying to get an used one (from scarp dealers). Will have to test it on lathe if found.

Have asked to a local Mahindra spare parts dealer and he told me to wait for two days.

I am in a dilemma whether to try the cut-and-weld one more time or bye a new one or an used one.

Arka,

Can you point me to your post on building custom propeller shafts? I searched it but no luck.

[AVR]

If you are going to change your differential to a driver-side offset setup then you'll not need a custom prop shaft as the regular ones are easily available. You can come to Ahmedabad and i'll help you find the right prop shaft.
Cheers
Adi

[HJ13]

Hello AVR,

Well as a neighbor, I was expecting you

In fact, I am in Ahmedabad till Friday. How can I PM you? Or can you PM your number to me? I am new to the Forum.

Thanks.

[AVR]

mail me on aditya.rathore at gmail and we'll talk. Hope I can be of help.

Adi

[MexXxentric]

Originally Posted by HJ13

Just an update:

After adding Tcase, the old 2WD rear shaft was cut and welded for reuse. And perhaps that resulted in increased vibration while driving (may be because it is crossed - not aligned to Tcase output?). A friend who has a Lathe told me that the welding process will ruin the alignment or weight balance of the shaft. Only options is to weld the shaft while aligning it on lathe - and that is not possible here.

Also trying to get an used one (from scarp dealers). Will have to test it on lathe if found.

Have asked to a local Mahindra spare parts dealer and he told me to wait for two days.

I am in a dilemma whether to try the cut-and-weld one more time or bye a new one or an used one.

Better get a new one & stay off custom made parts. Custom made prop. Shaft wont have correct dynamic balance &so induce more wear on the u joints,vibration will another issue.

Keep 'Used one' as second option. (will the dealer allow to check trueness to be on lathe)

[Suresh Stephen]

Originally Posted by svsantosh

Arka, some inputs here as to why' please? There are times where I have engaged 4Lo without locking the hubs and driven for few seconds before realizing it. Hope small errors are Ok?

Santhosh,
If 4Lo is engaged without locking the hubs, all the torque will be shared by the two rear axles. It is quite high and can twist the axles.
Suresh

[HJ13]

Arka and MexXxentric, thanks for your valuable input.
AVR, it was nice talking to you, thank you brother.

Updates:

1. During my stay at Ahmedabad, I left the jeep at my father's house where he drove the jeep and decided it needed a good wash and full greasing. When I came back and drove the jeep, I found my problem #1 (more revving, less power) and #4 (tight running - reduced free rolling) 75% solved
   
   Then I realized that after 4WD conversion, I got only the propeller shaft greased. I was under the impression that as the jeep had undergone full greasing just before the conversion, all I need is to made the propeller shafts greased The Tcase and front differential oil was already changed. So I am feeling happy and stupid at the same time.
   
   Need to check mileage(problem #5) and top speed now (#3).
   
   I still need to use 1st gear to start from stand still but the feel of power loss in other gears is not that much strong now.
   
   BTW Free Wheeling Hubs at Lamda enginnering are out of stock. Mr. Arun told me to inquire after 10 days.
   
   
   
2. Got front propeller shaft.
   Dealer: Venus motors, Mirzapur, Ahmedabad.
   Price: 1500
   
   
   
   
   
   
   
   
   
   
   
   But it fall short due to wrong measurement taken by me.
   
   Searched the Internet on how to correctly measure the propeller shaft (particularly how much the tube should travel/slip in the yoke). People says that the technique is to bottom out the shaft first and than pull it back from the yoke upto 1", and then to measure the length from one U-joint center line to another U-joint center line.
   
   For me it is difficult to estimate the length of the rear propeller shaft as current differential is centered
   If somebody has the length readily available, please share.
   My calculation is:
   Front shaft - 25" + 1" travel in yoke
   Rear shaft - 31" + 1" travel in yoke
   Provided this figures to Venus motors - waiting for their call.