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I recently bought a 1987 Commanche 4 cylinder, 4WD,  manual transmission. Can I tow (bar) behind my RV? It has a neutral setting on the  2wd / 4wd selector. 

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I'd say yes, everything in a manual drive line (except the engine) has a gear bath, so it should be fine. 

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1 hour ago, levans75433 said:

I recently bought a 1987 Commanche 4 cylinder, 4WD,  manual transmission. Can I tow (bar) behind my RV? It has a neutral setting on the  2wd / 4wd selector. 

I think you are supposed to remove the driveshafts for long tow like that.  The transfercase spins with the front tires and without the Jeep running the pump doesn't lubricate the gears properly or something like that.  Don't quote me on it but I'm like 95% sure that's the case.  I'd do some more research and wait for more definitive responses.

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11 hours ago, Dzimm said:

I think you are supposed to remove the driveshafts for long tow like that.  The transfercase spins with the front tires and without the Jeep running the pump doesn't lubricate the gears properly or something like that.  Don't quote me on it but I'm like 95% sure that's the case.  I'd do some more research and wait for more definitive responses.

I'm pretty certain the transfer case is a gear bath, not a pump, just like a manual transmission and differentials. No need to remove shafts. Your thinking of an automatic transmission, which does have oil pumps.

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22 minutes ago, PFCLeist said:

I'm pretty certain the transfer case is a gear bath, not a pump, just like a manual transmission and differentials. No need to remove shafts. Your thinking of an automatic transmission, which does have oil pumps.

The transfercase definitely has a pump in it but the gears do sit in fluid.  I'll do some digging for info but I am almost positive I've heard you need to remove the shafts per Chrysler instruction.

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After some digging around I found the info.  

 

For your truck you will want the transmission in 2nd or 3rd gear (park for an auto) and the t-case in neutral.  This way the trans won't spin.  You are also supposed to stop every 200miles and run the Jeep for a minute or so to lubricate the transfer case and it's recommended by some guys to so more often as they have had issues doing this.

 

To avoid that headache, remove the driveshafts.

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keep in mind that pulling the rear shaft can allow fluid to escape the t-case.  I've seen where guys unbolt the rear shaft from the axle and then use a ratchet strap to hold it up to the underside of the truck

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18 hours ago, Dzimm said:

I think you are supposed to remove the driveshafts for long tow like that.  The transfercase spins with the front tires and without the Jeep running the pump doesn't lubricate the gears properly or something like that.  Don't quote me on it but I'm like 95% sure that's the case.  I'd do some more research and wait for more definitive responses.

 

Correct. The early transfer cases have a Neutral position that disconnects the engine from the driveline, but it leaves the front and rear axles locked together and not disconnected from the transfer case. Jeep didn't change that to a true Neutral until some time in the mid- to late 90s. If you want to tow it, drop both driveshafts.

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2 hours ago, Eagle said:

 

Correct. The early transfer cases have a Neutral position that disconnects the engine from the driveline, but it leaves the front and rear axles locked together and not disconnected from the transfer case. Jeep didn't change that to a true Neutral until some time in the mid- to late 90s. If you want to tow it, drop both driveshafts.

That must be what I'm thinking of, then. I have a 99 NP231, and never heard of an onboard pump. I learned something today, thanks. 

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10 hours ago, Dzimm said:

The transfercase definitely has a pump in it but the gears do sit in fluid.

 

with the gears in neutral and the pump not working, only the lower part of the gears get oil...

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11 minutes ago, omega_rugal said:

 

with the gears in neutral and the pump not working, only the lower part of the gears get oil...

Correct.  There would be a small amount of oil carried up to the top from the chain but not nearly enough to lubricate everything properly. 

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I have not taken apart an early style 231, but as far as I know the lubrication system has not changed in them through the years. The tcase has a pump in it. The pump is driven off the output shaft which means if the rear driveshaft is connected and spinning the tcase is being oiled. If I were to flat tow my Jeep with a 231 tcase I would pop the tcase in neutral, trans in park and not think twice about it for any distance because as far as I’m aware it’s no different than if the Jeep were driving since it’s being oiled. That is my opinion on the matter and I might be wrong, but that’s how I would do it.


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12 hours ago, SatiricalHen said:

I have not taken apart an early style 231, but as far as I know the lubrication system has not changed in them through the years. The tcase has a pump in it. The pump is driven off the output shaft which means if the rear driveshaft is connected and spinning the tcase is being oiled.

I am about 95% certain your response is correct.  The NP231 has a pump oil pickup point at the bottom of the ‘driven’ chain sprocket, and the pump is part of the output shaft.  That means anytime the rear driveshaft is turning, the pump is running, regardless of what position the TC selector is in.

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the big debate is whether the early 231s are exactly the same inside as later 231s.  :dunno:  someone somewhere has pulled one apart!  just need to find that person :L:  anyone want to sift through a bunch of youtube vids?

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If someone gives me an early 231 I’ll gladly take it apart. I just don’t have any transfer cases older than 1999. If this was a 1999 I would feel very confident saying throw it in neutral and tow it. I guess one could study the exploded diagrams of the 2 cases.


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there could be friction between the input $#!&, which is stationary, and the output shaft, which is being turned by the rear wheels, similar to how a sm465 can destroy the 3rd gear if towed with the shafts on

 

input and output shafts must turn, if one doesn´t turn there´s friction

 

being in neutral has little or nothing to do with it

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I checked the shop manual for the 1988 NP207 and NP231 transfer cases.  They both show a gear type pump attached to the output shaft of the transfer case.

 

This would imply that, whenever the rear propeller shaft is turning, the transfer case lubricant is be moved by the oil pump contained therein.   That means it's safe to flat tow a Jeep with one of these transfer cases indefinitely without fear of damage due to lack of lubrication.

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