Borg Warner Automatic transmission

Rusty Gold

New member
Hi fellow IH fans I recently purchased a 2 wd 1970 3/4 travelette with a borg warner automatic transmission. The truck has a 392 with a 4 barrel holly and points ignition. The truck also has ps, pb, and a/c (not working ). I think the rear gear is 4:10 the line sheet is tore and the tag is missing off the diff. The question is 1) what type of fluid does this tranny require I May have added the wrong stuff. 2) while this trans does function correctly I really enjoy driving this and would like to get it up to hi way speeds any thoughts on a gear vendors along with changing the ring and pinion. Then again maybe just changing the diff ratio only. Or am I better off to do the conversion to a Chevy transmission? Is the borg auto reliable? And I don't want to harm the value not sure what the mods do to resale, although the kids love this truck and I don't see it leaving the family after only 3 months. Thanks for any input.:icon_rotate:
 
hi fellow IH fans I recently purchased a 2 wd 1970 3/4 travelette with a borg warner automatic transmission. The truck has a 392 with a 4 barrel holly and points ignition. The truck also has ps, pb, and a/c (not working ). I think the rear gear is 4:10 the line sheet is tore and the tag is missing off the diff. The question is 1) what type of fluid does this tranny require I May have added the wrong stuff. a. Check the dipstick for this info. And check the owners manual. (type "f" is probably fine.) the manual can be purchased online. 2) while this trans does function correctly I really enjoy driving this and would like to get it up to hi way speeds a. It drove hi-way speeds in 1970 when it was new (70 mph) so it should now as well. Any thoughts on a gear vendors (very expensive) along with changing the ring and pinion. Then again maybe just changing the diff ratio only. Or am I better off to do the conversion to a Chevy transmission? a. I would pull the diff cover off to change the fluid and determine the ratio first. Is the borg auto reliable? a. Yes it is. It lasted 46 years so far didn't it? and I don't want to harm the value not sure what the mods do to resale, although the kids love this truck and I don't see it leaving the family after only 3 months. Thanks for any input.:icon_rotate:

I would fix whatever is causing it to not drive properly on the hi-way before contemplating any modifications.
Proper tune-up with high quality parts, carb refresh, coolant flush w/proper Robert shaw thermostat and good 13# radiator cap.
My truck has a v-392 engine and 4.88 rear gears and it drives on the interstate just fine.

A trans upgrade to a GM 700r4 or similar would not devalue the truck and would be the least expensive and most reliable overdrive option. Seamless to drive as well.

The borgwarner auto was used in many vehicles of the era: amc, jaguar, some fords, IH, range rovers, etc. ...parts are still available with some diligent searching.

Iirc, type 'f' or 'fa' auto trans fluid is used in these bw autos. Should be easy to find either one of these.

Yours is probably the borg warner m-12 three-speed auto trans, iron case with aluminum bell housing. These typically have a separate water cooled trans fluid cooler mounted to them. The torque converter is also finned and provides cooling via airflow it creates around itself with screens in the bell housing for airflow.

If your water cooled trans fluid cooler is bad, marine (power boat) supply shops have similar units in stock as utilized in power boats, or you can remove the original cooler and install the typical air-to-air auto trans fluid cooler in front of the radiator.
 
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I did some more checking this weekend I found an old tach and down loaded a speed app to the phone just to double check. I used the mile markers on the road and across 2 miles at 3,000 rpm I averaged 58 mph. At 3,500 rpm I am at about 70 mph. Every thing I am told says absolutely do exceed 3,500 rpm for very long periods of time or it will shorten the life of the engine. Although it is still accelerating at 3,800 rpm I believe that the trans and every thing else is functioning correctly, basically I am gear bound. If I were able to find am od box for a decant price (used) do you think that the borg could handle the extra torque? I would also like to pull maybe a 20 ft camper or is the thought still the same; convert to the Chevy transmission with od. It is all work and money and I prefer to do it once I appreciate your input. By the way it has a cast iron bell housing still a borg I guess.
 
IH sv8 engines were designed to run at maximum rpm rating for continuous duty cycles for the life of the engine. They were installed in a variety of applications, including prime movers and stationary agricultural fixtures. In the case of your 392, that speed is 3800 rpms. Naturally, the thing is howling like wolfman jack on steriods at that speed, which doesn't make for the most pleasureable driving experience, but it won't hurt the engine, so you can put that fear aside.
 
You beat me to it trever, and I'll add that most of that noise is the direct drive cooling fan.
My truck does the same and it has 4.88 gears, but I know the rpm's at various hi-way speeds so I know I am not hurting the engine.
Those little foam earplugs come in handy on freeway journeys.
 
Thanks for the help. This is reminding me more of a diesel engine characteristics makes sense because of the other applications. In the past ear plugs gane me 5-10 mph. Lol. Great forum thanks for the help. :icon_rotate:
 
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