1998 D1 SD transmission temp

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Hello! First Post!

I've been driving this white discovery off and on since 2010 and making repairs along the way. I've always wondered if the transmission and gear box temperature were too hot. I changed the gear box oil back in 2014 but it still ran "hot," so I just thought that was normal temp range. Now as I prepair for a cross country drive to California, I was wondering if other D1 drivers had the same experience. I measured the temp at 160F with an IR temp guage. Has anyone else ever measured the normal operating temp of there transfer case and transmission? If so please let me know or make a measurement and report back.

Best Regards

 

[DiscoClay]

Is this a manual transmission (R380) or an automatic transmission (ZF 4HP22)?

The R380 has that silly (IMO) plastic pump that is used to spray the top of the gearset (needed because the spec'd oil is actually ATF hydraulic fluid rather than 'proper gear oil'). It also pushes the atf through the cooler, so that's...cool. Hopefully someone else will pipe in here and educate me, as I have not physically broken down an R380 (plenty of Ford Toploaders, Muncie m21 and m22's and several T5's back in the day though).

I spoke with a Redline engineer about the R380's unique configuration (thanks to fuel efficiency efforts) and he recommended MTL-75W80 (https://www.redlineoil.com/mtl-75w80-gl-4-gear-oil) and said I could probably get away with MT-90 (Red Line (50304) MT-90 75W-90 GL-4 Manual Transmission and Transaxle Lubricant) as the max viscosity I should attempt to use..due to that pump having nylon components and maybe not standing up to the thicker oil.

I went with the MT-90. When the wagon is cold, it is stiffer and the 1-2 synchro grinds a little more.. also shifting directly into reverse can be more sticky. That said: once everything is warmed up.. ESPECIALLY after full heatsoak from a few hours of highway driving... the tranny shifts WAY better than it did with the original ATF. Pick your poison, but make it redline (imo).. I have had great reliability with their stuff over the years: https://www.redlineoil.com/

 

[terryjm1]

This is what I use in my R380 gearboxes. One, rebuilt with 15,000 miles and another with 60,000 since new. Both shift perfectly no matter cold or hot. One doesn’t have an oil cooler.

 

[DiscoClay]

I would like to find a rebuildable R380 on-the-cheap.. I hate the 1-2 synchro grind.

MTL is a fantastic product.. and they actually answer the phone like a human.. and will talk to a nobody like me, to sort things out! Five stars.

 

[DiscoClay]

This is what I use in my R380 gearboxes. ...One doesn’t have an oil cooler.

Does this one also lack the internal pump?

 

[terryjm1]

I have one that is locked up. No bellhousing and a few other bits missing but it’s all external parts and if you are swapping it in you could grab those bits. I have no idea why it’s locked up. I purchased a parts vehicle and no prior history was known. It had 125,000 on the odometer. I was going to take it apart for practice but probably will not.

I would like to find a rebuildable R380 on-the-cheap.. I hate the 1-2 synchro grind.

MTL is a fantastic product.. and they actually answer the phone like a human.. and will talk to a nobody like me, to sort things out! Five stars

 

[terryjm1]

Does this one also lack the internal pump?

I think they all have the pump. Where the cooler / thermostat assembly is on the gearbox it has a bypass fitted. It’s in a 300tdi, so I never tow with it. I just do not think a cooler is needed unless you tow. I think the cooler is an NAS thing.

 

[DiscoClay]

Got it. I really need to get ahold of a spare disco R380 to rebuild myself.

 

[Envelope]

Is this a manual transmission (R380) or an automatic transmission (ZF 4HP22)?

The R380 has that silly (IMO) plastic pump that is used to spray the top of the gearset (needed because the spec'd oil is actually ATF hydraulic fluid rather than 'proper gear oil'). It also pushes the atf through the cooler, so that's...cool. Hopefully someone else will pipe in here and educate me, as I have not physically broken down an R380 (plenty of Ford Toploaders, Muncie m21 and m22's and several T5's back in the day though).

I spoke with a Redline engineer about the R380's unique configuration (thanks to fuel efficiency efforts) and he recommended MTL-75W80 (https://www.redlineoil.com/mtl-75w80-gl-4-gear-oil) and said I could probably get away with MT-90 (Red Line (50304) MT-90 75W-90 GL-4 Manual Transmission and Transaxle Lubricant) as the max viscosity I should attempt to use..due to that pump having nylon components and maybe not standing up to the thicker oil.

I went with the MT-90. When the wagon is cold, it is stiffer and the 1-2 synchro grinds a little more.. also shifting directly into reverse can be more sticky. That said: once everything is warmed up.. ESPECIALLY after full heatsoak from a few hours of highway driving... the tranny shifts WAY better than it did with the original ATF. Pick your poison, but make it redline (imo).. I have had great reliability with their stuff over the years: https://www.redlineoil.com/

It is an automatic transmission. I don't know the exact model number. Were they all the same for US models from 94-99?

I read the transmission fluid doesn't start breaking down until 300F, so I stopped worrying about it being 160F.

I made the post and was unsure about driving it to California, 1800 miles. Just finished the trip and made some steep grades in the Sierra Nevadas. With the cooler air the transmission didn't get as hot. On the steep grades I ran in second and third gear at 3000 rpms. Half way up Kingsbury grade the temp was 150F. There was a bit of a smell, but the temp seemed fine.