Engine/Transmission (1994 - 1998) Whining OD in 47RE

[BSMcCauley]

I've started noticing a whining noise from the transmission when in overdrive, similar to the sound of my old '64's manual box in 3rd gear, though not quite that loud. Noise the same regardless of power output, even downhill, no throttle, 30 mph. Force it out of OD with the button and noise instantly quits. Back into OD, and noise back before the shift finishes. Truck well maintained, Amsoil in transmission at proper level, guessing 80% of the 240,000 miles on it has been running empty and rarely pull a utility trailer. Is this something I should be concerned about?

PS: '96 2500, 4x4, auto, 3. 54 gears, bone-stock engine & transmission except for mystery switch.

 

[bmoeller]

Sounds like the O/D unit needs a bearing or rebuilt. Good thing is, it can be pulled off of the back. With that many miles though, you might want or need to consider a full rebuild.

The stock valvebody tends to not lube the O/D very well. Get a modified one, and you won't need to check the oil lever with it in neutral, and will flow more lube oil. Trans will probably run a bit cooler, too.

Had my stock trans replaced at 190k. Found the O/D clutch was burnt up as was one other. The sun gear in the O/D was bad as well. The guy at Goerend's said someone had been in the O/D before, which I had suspected. Looked like it had been off before.

 

[BSMcCauley]

Appreciate the feedback. Quick question: looks like you're truck has had several performance mods, did you have the transmission trouble before or after applying those? The bearing theory is a good point. Now to decide how long is the fuse on bomb -- how long can I run it like this and still have a good core for the trany exchange????

 

[JoeBioDiesel]

I agree with bmoeller. It sounds like a bearing in the OD unit is going south. I recommend you fix it now, and not after it grenades. It will be cheaper now. It is also possible to lose all forward(and rearward) motion if you burn up the OD unit. It has one clutch that is applied in all gears except OD as well as one that appies in OD. If you burn them both(like can happen when the bearing on the apply piston goes) the truck will leave you sitting.

 

[BSMcCauley]

Anyone got any recommendations for a good transmission rebuild shop in the Houston, TX area?

 

[JVolpe]

Call Michael at HotRodDiesels.com. They are in Hitchcock just south of Houston on Highway 6. He did my trans and many others in the area. Specializes in Dodge Cummins TC/Trans along with all general diesel repair/maintenance and performance. He has done all of the wrench work on my truck for the last 3+ years now. I would recommend him to anyone with a diesel, especially a Cummins.

 

[BSMcCauley]

Thanks for the tip. I'll check them out if I don't find someone in Montgomery County.

 

[BSMcCauley]

After phone consultation with Michael at Hot Rod Diesels, I made the 90 mile drive to Hitchcock, TX with the overdrive locked out and left the truck with him for a performance rebuild of the transmission and performance TC & flexplate replacements. Learned yesterday that in addition to the failing bearing in the OD that I already knew about, the input shaft was very close to letting go as well -- even with the engine still at as-delivered power level. Feeling very blessed to have avoided a very close call for the wife being stranded out in the middle of Nowhere, West Texas, having just returned from a work-related 1250 mile round-trip solo to SE NM. Now with transmission upgrade in progress and Christmas bonus in hand, my letter to Santa is gaining some fresh entries for a few under-hood items I've been wanting for quite some time... .

 

[RStankevitz]

let us know how santa treats you and how it works out i have to wait till jan 15th my tc slips like no tommorow so i cant wait. course turning the pump up and more boost probably didnt have anything to do with that:-laf

 

[bmoeller]

Appreciate the feedback. Quick question: looks like you're truck has had several performance mods, did you have the transmission trouble before or after applying those?

Was slipping stock, but started adding power anyways. :-laf I went in this order- 10 plate, PDR HX40 and 370 marine injectors. That worked for 6mths after the injectors went in, then the transmission said no more. :-laf Did the trans, then I did the 191s, DPP4's and HTT turbo. Slid the plate full forward after the trans went in. Works like a charm. Oo. Oo.

 

[BSMcCauley]

Picked up truck from Hot Rod Diesels last week. Michael had the bad OD bearing and input shaft sitting on the counter when I got there. Bearing was so rough it's hard to believe it was still rolling. Spinning by hand, it had a catch that would jam it once in a while. Input shaft had slack between the shaft and drum, i. e. splines beginning to fail. Now enjoying the lower stall TC getting more work done between 1250 - 1500 rpm that I had been getting out of the factory TC @ 2150. And the engine speed changes now with up-shifts instead of sitting against the governor. :-laf Pulled my 16' utility trailer the other day to haul 1200# of stuff for the swim team's food drive and barely even knew it was back there, would have had to floor it to get moving before, even empty, with the factory setup. :-laf Now for those power upgrades...